the blackett laboratory - imperial college london

Faculty ofPhysical Sciences 2003

Departmentof PhysicsReview

TheBlackett

Laboratory

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The Blackett Laboratory at Imperial College is the academichome for hundreds of physicists, from undergraduates toprofessors. When the building went up at the end of the1950Õs it was said to be the most expensive departmentalbuilding in the country. ItÕs certainly one of the nicest towork in, but for some time has needed sprucing up. Thedepartment, with a lot of help from College put in verysubstantial resources to improve the infrastructure during2003. Labs were refurbished, corridors moved andbrightened up, and the entrance from Prince Consort Roadgiven a whole new look. Visitors are now greeted by anattractive and well-lit social area, which seems always tobe buzzing with activity. The department is flourishing,buoyed by our top ranking in the Research AssessmentExercise and by the high quality of our students who choseto study with us.

Physics Department staff received many external awardsand prizes during 2003. Professor Peter Dornan waselected to the Fellowship of the Royal Society for his workin high energy physics. Professor Joanna Haigh wasawarded the Chree Medal and Prize of the Institute ofPhysics for her work in atmospheric physics. ProfessorMartin Plenio was awarded the Maxwell Prize of theInstitute of Physics for his work on quantum informationprocessing and quantum computing. Prof Donal Bradleywas a member of the team awarded the Descartes Prizefor work in molecular electronics and light emitting polymers.Prof Chris Dainty was awarded the Mees Medal and Prizeof the Optical Society of America (and I was the OSAÕsPresident-Elect in 2003). EPSRC awarded a SeniorFellowship to Prof John Pendry FRS so that he coulddevote his time to research into the new metamaterials hehas been pioneering. PPARC awarded Senior Fellowshipsto Prof Peter Cargill, Dr Ken Long, and Dr MicheleDougherty. Martin Plenio was awarded a Senior fellowshipby the Royal Society and the Leverhulme Foundation.The student Physics Society had a really active year;they were recognized by the Institute of Physics throughthe award of its Òbest physics society award.Ó

Many new appointments were made to the academicstaff in 2003. Following a major review of the TheoreticalPhysics Group, a new String Theory Initiative broughtProfs Chris Hull and Jerome Gauntlett and Drs FayDowker and Dan Waldram to Imperial from Queen Mary.The new Centre for Cold Matter was formed led by ProfEd Hinds and Dr Ben Sauer, who came to us fromSussex, and they already have a Bose-Einstein condensaterunning in their new labs. The High Energy PhysicsGroup have launched a major new initiative in neutrinophysics and we welcomed Prof David Wark and Dr YoshiUchida to the academic staff to lead this effort. Dr KenLong in the HEP group organized a major conference atImperial on the proposed new neutrino factory, and ahighlight was a dinner in the Flight Gallery of theScience Museum with Lord Sainsbury, the ScienceMinister, as guest speaker. The department has played alead role in the establishment of the new MathematicalSciences Institute at Imperial, which will host major inter-disciplinary research collaborations. The department hasalso done well in winning major Basic Technology grantsfrom Research Councils UK in attosecond physics,plasma physics, optical imaging and condensed matterphysics. The Photonics group led by Prof Paul Frenchwere awarded a major DTI Beacon Award for their workin biomedical imaging. All of these point to the continuingresearch vitality of the department.

Finally let me end on a sad note: in 2003 we saw thedeaths of two leading figures in the department: ProfTony Stradling, who brought semiconductor physics tothe department and guided our work in the departmentand within the IRC in Semiconductor Growth with hugedistinction; and Dr Betty Johnson, who played a majorrole in the establishment of the Daphne JacksonFellowship scheme for science returners as well asresearching in condensed matter theory.

P. L. Knight FRSHead of DepartmentOctober 2004

The cover: A dramatic infrared image of a dust globule from NASA's SPITZER Space Telescope, with which the Astrophysics Grouphas a strong involvement.

Preface from the Head of Department

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Plasma Physics

Space andAtmospheric Physics

Astrophysics

TheoreticalPhysics

Page 34

High EnergyPhysics

Head of Group:Professor P J Dornan

Head of Group:Professor K Stelle

Head of Group:Professor

M Rowan-Robinson

Head of Group:Professor J E Harries


K M Krushelnick

Director:Professor J P Marangos

OpticsQuantum Optics

and Laser Science

Head of Group:Professor J P Marangos

Page 16

Page 31

Page 25

Page 28

Page 19

ExperimentalSolid State

Physics and Centrefor Electronic Materials

and DevicesHead of Group:

Professor D Bradley

Page 10

OpticsPhotonics

Head of Group:Professor P M W French

Page 22

OpticsLaser Consortium


D D Vvedensky

CondensedMatter Theory

Page 7

For contact addressessee page 53

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The Blackett LaboratoryGeneral Departmental Information

Undergraduate and Postgraduate Studies

Head of DepartmentProfessor P. L. Knight FRS

Tel: 020 7594 7500 Fax: 020 7594 7504

e-mail: [email protected]

Associate Head of DepartmentProfessor R. W. Smith

Tel: 020 7594 7501 Fax: 020 7594 7504


Director of Undergraduate StudiesProfessor R. C. Thompson

Tel: 020 7594 7505 Fax: 020 7594 7777


Senior Tutor (Undergraduates) :Dr R. J. Forsyth

Tel: 020 7594 7524 Fax: 020 7594 7777


Admissions Tutor (Undergraduates) :Professor W. G. Jones

Tel: 020 7594 7513 Fax: 020 7594 7777


Schools Liaison OfficerDr J. Hassard

Tel: 020 7594 7792 Fax: 020 7823 8830


Director of Postgraduate StudiesDr J. Sedgbeer

Tel: 020 794 7512 Fax: 020 794 7509


Director of Resource DevelopmentDr. R. G. Burns

Tel: 020 7594 7700 Fax: 020 7594 7777


Undergraduate Teaching Page 37(Queries about undergraduate admissions should be addressedto the Admissions Tutor)

Schools Liaison http://www.imperial.ac.uk/options/ Page 40

Postgraduate Studies - Page 41

MScProspective postgraduate students interested in admission for an MSc course should contact the appropriate course organiser listed below.

MSc in Optics and PhotonicsDr. K. Weir, Tel: 020 7594 7723, Fax: 020 7594 7714, e-mail: [email protected]

MSc in Quantum Fields and Fundamental ForcesDr. J. Halliwell, Tel: 020 7594 7831, Fax: 020 7594 7844, e-mail: [email protected]

PhDThose interested in admission for doctoral level research leading to the PhD degree should contact the Heads of Research Groups in subject areas of interest as listed opposite.The Director of Postgraduate Studies will be glad to advise on all general matters concerningthe requirements for admission as a postgraduate student.

http://www.imperial.ac.uk/physics

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Head of Group:Professor M. Rowan-Robinson

T. J. Sumner, W. G. Jones (HEP), I. Liubarsky, J. J. Quenby, G. K. Rochester, H. Araujo, A. Bewick, C. Bungau (RAL), D. Davidge, J.V. Dawson, A. S. Howard (HEP), V. Lebedenko,C. G-Y. Lee (SPAT), R. Luscher, D. Shaul.

Search for Dark Matter ParticlesParts manufacture for ZEPLIN III, ournext generation two-phase xenondetector for dark matter search, is now95% complete. The dark mattersearch is looking for signatures ofdirect interactions of exotic newparticles in the Boulby undergroundfacility. Our work is being done withinthe UKDMC collaboration (RAL,Sheffield University, and Imperial)which currently has some of the bestresults in the world from a simplersingle phase liquid xenon scintillationtarget, ZEPLIN I. This uses a pulseshape discrimination technique toseparate the interesting nuclearrecoil signals from the much moreabundant background due to normalradioactivity in the instrument and itsenvironment. ZEPLIN III (Fig.1)should achieve about 2 orders ofmagnitude better sensitivity within afew years and this will maintain ourworld leading position, and pave the

way for larger targets with up to 1tonne of xenon.

Gravitational Wave AstronomyThe detailed design of the ChargeManagement System for the LISAPathfinder technology precursorsatellite to gravitational wave sciencemission, LISA, of the European SpaceAgency is complete (Fig. 2). We aredeveloping an Engineering Model,both for ESA and NASA. Thissystem is required by LISA to controlthe charge build-up on the isolatedproof-masses, which form the mirrorsfor the large baseline interferometrybetween the three spacecraft in theconstellation. Charge build-up iscaused by cosmic-ray impacts on thespacecraft and proof-masses.Gravitational wave astronomy fromspace was highlighted as a highpriority area for PPARC funding inthe recent Government spendingreview, with additional earmarkedcentral resource. PPARC haveapproved funding for Imperial tocover the LISA-PF European flightsystem.

Neutrino Astrophysics: TheAstrophysics Group is formally partof the AMANDA and ICECUBEcollaborations. Our scientific interestis in the connection between neutrinoemission and gravitational waves,which would be expected in some ofthe more extreme forms ofcollapse/explosion of astrophysicalobjects.

Building on the success of AMANDA-II,the largest neutrino telescope in theworld, the international collaborationis currently constructing ICECUBEwhich when completed in 2008 willencompass 1 km3 of instrumentedSouth Polar ice and should besensitive enough to commenceexploration of the neutrino observa-tional window (Fig. 3).

J. E. Drew, W. P. S. Meikle, Y. Unruh,L.Lucy, M. Pozzo, S. Sim, R. Kotak,J. Vink.

Ha emission line survey of theGalaxy We are leading two largeinternational collaborations that aimto explore the entire Milky Way foremission line stars and compactnebulae down to a limiting redmagnitude of almost 20. By pushingdown 500 times fainter than the1960s-generation of Ha Galacticsurveys, these programmes shouldincrease the number of knownemission line objects by more than afactor of 10 (Fig. 4). This in turnshould revolutionise our under-standing of the early and late stages

Astrophysics

Experimental Astrophysics

Galactic Astrophysics

http://www.imperial.ac.uk/research/astro

Figure 1: This shows one of the criticalparts of ZEPLIN III, made out of purecopper with stainless steel feedthroughs,being vacuum tested. Very clean electron-beam welding has been used to weldboth copper and stainless parts together.

Figure 2: Inertial Sensor design work forLISA. A view of the engineering model ofthe Charge Manage-ment System for theEuropean LISA Test Package (LTP) to beflown on LISA-PF, being developedunder contract to ESA.

Figure 3: IceCube will occupy a volumeof one cubic kilometre. Here we depictone of the 80 strings of optical modules(number and size not to scale). IceToplocated at the surface, comprises anarray of sensors to detect air showers. Itwill be used to calibrate IceCube and toconduct research on high-energy cosmicrays.

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of stellar evolution Ð the latter, inparticular, remain very poorlysketched out.

In the southern hemisphere, we areengaged in spectroscopic follow-upof candidate emission line starsderived from the already completeAnglo-Australian Observatory SchmidtHa Southern Galactic Plane Survey.We have already made one spectaculardiscovery of a rare and particularlyextreme Wolf-Rayet (WO) star: thisobject increases the available Galacticsample to just 4 stars and also breaksthe record for observed maximumwind speed (5750 km/s) and carbonabundance (C/He = 2.85, by mass).

Young stars A continuing interestconcerns the intimate circumstellarenvironments of young stars, at allmasses, still accreting matter. Themain observational tool used toexplore these environments continuesto be high (spectral) resolutionspectropolarimetry, mostly performedon the often-observed, bright Haemission line.

In 2003, attention focused on thelower mass solar-type young stars(T Tauri stars). We wanted to learnif the T Tau stars exhibit the samepolarimetric behaviour as the HerbigAe stars Ð it is becoming evidentthey do, hinting at no real change inthe accretion geometry betweenthese two groups of stars. The bestobservations obtained were of RYTau: these have demonstrated thatthe common presumption of nosignificant linear polarization changesacross Ha in T Tau-star spectra isunfounded.

The Sun as a star Work continues onmodelling solar and stellar irradiancevariations. We have produced verysuccessful solar irradiance models,invoking only changes in the surfacemagnetic field, that fit the observeddata on timescales from days todecades. For shorter timescales ofdays to hours, we have started todisentangle variability due to magneticsurface features and convection,and are investigating how this scalesto stars with different spectral types.Our findings will aid detection of

planetary transits made by theCOROT mission.

Numerical modelling of supernovaeThe previously-developed transitionprobabilities for Monte Carlo energypackets were used successfully tocompute a NLTE solution for theouter layers of a type II supernova.Encouraged by this, work has startedon applying the technique to thegeneral time-dependent radiativetransfer problem for supernovae ejecta.In parallel we have been developingobject-oriented code, exploiting thesesame techniques, to achieve easygeneralisation to 2- and 3-D media.

Supernovae A major problem inunderstanding thermonuclear (TypeIa) supernovae is the nature of theprogenitor - a particularly importantproblem since these supernovae haveprovided the key evidence for anaccelerating universe. An importantstep would be the observation ofcircumstellar material. A 2003 highlighthas been our discovery, using theUnited Kingdom Infrared Telescope,of a large mass of circumstellar dustaround the peculiar Type Ia Supernova2002ic. This followed the earlierdiscovery (by observers in Chile) ofhydrogen in the supernova spectrum.Using the Very Large Telescope inChile, we have also obtained conclusiveevidence that the hydrogen musthave been released as a wind bythe progenitor.

Another major goal is to establishwhether or not supernovae aremajor sources of interstellar dust. Amajor component of this work hasbeen our recently completed infrared/optical study of the Type IIn Supernova1998S which has provided strongevidence of at least 10-3 solar massesof dust associated with this ratherunusual type of supernova. Whilesome of the dust actually formed inthe progenitor wind, it is likely thatthe interaction of the supernovashock with the wind also created anideal "nursery" where grains grew.

M. Rowan-Robinson, S. Warren, A. Jaffe, K. Nandra, M. Fox, S. Dye,L. Mendes, R. Priddey, D. Clements,D. Rosa, T. Takagi, P.OÕNeill, D. Novikov, I. Valtchanov, K. dÕMellow,M. Vaccari

Infrared and submillimeter surveysThe first data have been receivedfrom the SWIRE Legacy Survey,being carried out with NASAÕs SpaceInfrared Telescope Facility (SPITZER),launched in August 2003. This is thelargest survey project being carried outby SPITZER and is expected to yieldover a million infrared galaxies, in thewavelength range 3 to 170mm (Fig. 5).

The final band-merged cataloguefrom the ELAIS survey, carried outwith ESAÕs Infrared Space Observatory,has now been released. Thecatalogue includes a high proportionof ultraluminous infrared galaxies. Anew population of luminous coolgalaxies has been identified, whichmay have implications for galaxyevolution theories. Photometricredshift techniques have provedpowerful in probing the infraredgalaxy population at reshifts 0.5-1.5.

With collaborators at Kent, Sussexand Groningen, the Group has beenworking on the data analysispipeline for the Japanese all sky farinfrared survey mission, ASTRO-F, duefor launch in August 2005. The Groupcontinues to work on the SHADES850 micron survey using the JCMTin Hawaii and on preparations for

Figure 4: A false-colour image derivedfrom 2 overlapping exposures taken aspart of the northern photometric Ha surveyin the autumn of 2003. This is of anebulous and dust-obscured field inCygnus that contains no known objects.Red colour corresponds to stars andnebulosity emitting in Ha.

Cosmology and ExtragalacticAstrophysics

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ESAÕs Herschel submillimetre mission.

Cosmic Backgrounds The Groupcontinues its role in ongoing experi-ments measuring the anisotropy ofthe Cosmic Microwave Background(CMB) radiation. MAXIMA andBOOMERANG, the first experimentsto use the CMB to unambiguouslymeasure the geometry of the Universe,have turned their attention to thepolarization of the CMB. Polarizationcan shore up these cosmologicalmeasurements and, eventually, probethe epoch of cosmic inflation that mayhave occurred in the first fractions ofa second after the Big Bang.Meanwhile, Imperial is developingsoftware for the analysis of datafrom the European Space AgencyÕsPlanck Surveyor CMB satellite, dueto be launched in 2007.

The Group is also involved in thetheoretical prediction of the backgroundof Gravitational Radiation that, inEinsteinÕs General Relativity, shouldsuffuse the Universe. We are calcu-lating the radiation from the mergersof Black Holes, millions to billionstimes the mass of our sun, residing inthe centres of galaxies. Eventually,these could be observed by the ESAsatellite LISA (whose hardware isalso being developed in the Group)and, in the more distant future, byNASAÕs Big Bang Observer satellite, inwhich Imperial Astrophysics hasbecome involved and for which aconcept study was just approved byNASA.

X-rays We are nearing completionand installation at Imperial of thefinal version of the "Tartarus" database,which contains fully reduced dataproducts for all ASCA observationsof active galactic nuclei (AGN). Ourlarge area, hard X-ray survey "SHEEP"has been completed, with followupChandra observations and groundbased optical spectroscopy nowunderway. We have performeddetailed analysis of the X-ray timevariability of several AGN, using RXTEand XMM-Newton data, in separatecollaborations with CambridgeUniversity, UCLA and the Universityof Crete. We have also used XMM-Newton to constrain the iron-K line

profile of the AGN IRAS 13349+2438,which shows evidence for the gravi-tational redshift of the black hole.

Dark Matter mass profiles ingalaxies A critical test of the colddark matter (CDM) paradigm forstructure formation is the measurementof the slope of the dark matterdensity profile in the central regionsof galaxies. We have applied our newsemi-linear inversion technique to thegravitational lens 0047-2808, toinvestigate this issue. The methoduses all the flux information in animage, and consequently we obtaingood constraints. The 95% confi-dence interval on the exponent ofthe inner power-law slope isconsistent with the predictions ofCDM simulations.

We have reanalysed the availabledata on the kinematics of Lyman-break galaxies (LBGs) at redshift z~3,comparing against the predictions oftheories of galaxy formation. Ouranalysis resolves a controversy overthe nature of LBGs favouring thelow-mass starburst model, over the

alternative model of single galaxiesat the centres of the most massivedark matter haloes at that epoch.

Figure 5: An early image from NASAÕs SPITZER infrared telescope. It shows acomposite of the famous galaxy Messier 81 as seen at infrared wavelengths. The bluecolours corresponds to 3.6 micron emission from stars in the bulge of the galaxy, theyellow and red colours to dust emission at 5.8, 8 and 24 microns, from star formingclouds in the disk of the galaxy.

7

Head of Group: Professor D. D. Vvedensky

K. Christensen

Since the laws of physics are simple,how come nature isn't? Whenlooking around, you find nature isapparently complex. The complexitymanifests itself, for example, inemergent properties such as simplepatterns, hierarchical structures,fractal structures or other scale-freebehaviour. The overall objective ofthe science of complex systems isto address why nature is complex,not simple.

K. Christensen, S. A. Collobiano, H. J. Jensen

The dynamics of the Tangled Naturemodel is defined on the micro evolu-tionary time scale via reproduction,with heredity, variation, and naturalselection. Each organism reproduceswith a rate that is linked to theindividuals' genetic sequence anddepends on the composition of thepopulation in genotype space. Thusthe micro evolutionary dynamics ofthe fitness landscape is regulated by,and regulates, the evolution of thespecies by means of the mutualinteractions. At low mutation rate, themacro evolutionary pattern mimicsthe fossil data: periods of stasis,where the population is concentratedin a network of coexisting species, isinterrupted by bursts of activity. Asthe mutation rate increases, theduration and the frequency of burstsincreases. Eventually, when themutation rate reaches a certainthreshold, the population is spreadevenly throughout the genotypespace showing that natural selectiononly leads to multiple distinct species ifadaptation is allowed time to causefixation. The mutation threshold hasbeen derived theoretically, therebyproviding a valuable insight into howthe microscopic dynamics of the modeldetermine the observed macro-scopic phenomena.

K. Christensen, O. B. Peters

We demonstrate that self-organisedcriticality may offer an alternative tothe chaos theoretic perspective onthe subject of rainfall. From the pointof view of energy flow through anon-equilibrium system, rainfall isanalogous to other relaxationalprocesses in Nature such as earth-quakes. The Sun provides the energyto evaporate water from the oceans.This energy is stored in the atmos-phere in form of vapour. Once in awhile, the energy is released, causinga rainfall. The number density ofrainfall events per year is inverselyproportional to the released watercolumn raised to the power 1.4. Theevent durations and the waiting timesbetween events are also characterizedby scaling regions, where no typicaltime scale exists. These findings areconsistent with the concept of self-organised criticality, which refers tothe tendency of slowly driven non-equilibrium systems to evolve into astate with scale free behaviourwithout the need to fine-tune anycontrol parameters.

W. M. C. Foulkes

Computer simulation is used in manydifferent contexts, but the underlyingquestions are often surprisinglysimilar. What happens when manysimple objects come together andinteract? How does the complexbehaviour of the whole emerge fromthe simple laws obeyed by its parts?The constituent objects range fromthe electrons and nuclei in a crystalof silicon to the cables and girders ina bridge, but the common aim is topredict the complex large scalebehaviour from the simpler smallscale behaviour. In almost all typesof computer modelling, some of thedata required for simulations on onelength scale can only be obtainedfrom the results of simulations on thelength scale below. This descent to

smaller and smaller length scalescontinues right down to the quantummechanical scale (roughly 10-10 m)at which the many-electron Schr�dingerequation at last provides a conciseand accurate universal law of nature.There are quantum field theoreticallevels below it, but the Schr�dingerequation requires no input from theseand serves as a natural root for thetree of simulations with branches atlarger and larger length scales.Attempting a direct solution of theSchr�dinger equation for a systemof thousands of interacting electronswould have been considered animpossibility a decade ago, but weand a few other groups have shownthat it can be done. The main errorsin the quantum Monte Carlo (QMC)methods we use are statistical innature and can be reduced simplyby increasing the run time. Usinglarge parallel computers, we cansimulate systems containing severalhundred atoms, which is enough tomodel most of the properties of mostmolecules and solids with greataccuracy. During the past year wehave continued our study of theelectronic properties of surfaces, atwhich subtle electron-electron inter-action effects are expected to beparticularly important. Thesesimulations have required severaltechnical innovations, including a newmethod for dealing with Coulombinteractions in quasi-two-dimensionalsystems, but are now close to complete.We are also working on a newapproach to the calculation of excitationspectra (more specifically, one andtwo-electron Green's functions) forreal solids and molecules. If wesucceed, we will have increased theusefulness and range of QMCmethods substantially.

D. K. K. Lee, R. Jack

When we put together a largecollection of atoms or electrons,order may emerge from their complexcooperative behaviour. Examplesinclude superconductivity and ferro-magnetism. A central challenge in

Condensed Matter Theory

Science of Complexity

Rainfall Viewed as RelaxationalEvents

Tangled Nature Model

Quantum Mechanical Modelling

http://www.imperial.ac.uk/research/cmth

Quantum Phases of Matter

8

condensed matter physics is thequestion: "how does the sum becomemore than its parts?" Theoreticalprogress in understanding such"emergent phenomena" can help ussearch for, and even design, newmaterials of practical importance.

D. K. K. Lee

I have recently studied the "quantumHall bilayer" which apparently violatesthe well-known Ohm's law for electricalconduction which states that thecurrent should be proportional to thedriving voltage. This system consistsof two parallel two-dimensional electrongases in a strong magnetic field.These layers are in close proximity onthe atomic scale in a GaAsheterostructure. The Coulomb inter-action between the electrons in thetwo layers drives a quantum phasetransition to an ordered state, akinto a ferromagnet (where all themagnetic moments point in the samedirection). Experiments have shownthat electrical transport across thetwo layers is drastically enhanced inthese bilayers at low temperatures.Surprisingly, the current across thebilayer may increase when the voltageis decreased! This violation of Ohm'slaw occurs over a wide range ofvoltages at low temperature. We arethe first to give a microscopic expla-nation of this phenomenon. We haveshown that the loss of quantumcoherence in this system is the keyto this puzzle. The short-term goalof the project is to provide a theoryof coherence in these systems whichcan be tested by experimentalists.Future research will explore howdisorder play a role in decoherence.From a wider perspective, this systemprovides a testbed for ideas aboutdecoherence in materials whichexhibit quantum order (such assuperconductors and ferromagnets).Understanding decoherence iscrucial to fulfilling the promise ofthese systems as candidates fornanotechnological applications.

A. MacKinnon, E. A. Johnson 11/9/03,M. A. Oliveira

The possibility of producing andmanipulating a spin-polarised currenthas several exciting applications,most notably in quantum computing.Although the use of magnetic materialsin such devices springs to mind thereare also non-magnetic means ofmanipulating electron spins, particularlythrough the Rashba effect. Most workon this effect has started with theassumption that it is necessary touse an artificial anisotropic structure,such as a semiconductor quantumwell sandwiched between two differentwider gap semiconductors. Suchsystems have structural inversionasymmetry (SIA). Using a computeralgorithm in which the properties ofthe layered semiconductor systemare calculated atomic layer by atomiclayer, we have been able to studythe electronic properties of a rangeof realistic and artificial structuresand gain a better understanding ofthe conditions necessary to separateelectrons according to their spinstate. A particularly significantresult is that the SIA is not necessary.Most semiconductors, with theexception of Silicon and Germanium,have bulk inversion asymmetry (BIA).When a quantum well is formed bysandwiching these materials betweenwider gap semiconductors a spin-splitting can arise which may be anorder of magnitude or more largerthan that of the bulk material andcomparable with that due to SIA.This result opens up new andunexpected possibilities for thedesign of spintronic structures.

A. MacKinnon, J. M. Carter

A full explanation of the physics ofelectrons in non-crystalline materialsnot only requires us to understandthe role of disorder but also theinterplay between disorder andelectron-electron interactions. Asdisordered systems and interactingsystems both represent difficult

problems in their own right, thecombination presents particularchallenges. At the present time it isonly possible to make progress onsimpler versions of the problem orusing approximations whose validityis open to challenge. We have chosento concentrate on 1-dimensionalsystems as a first step and havedeveloped a computational algorithmcombining elements of the traditionaltransfer matrix method for non-inter-acting disordered systems with thedensity matrix renormalisation groupused for interacting systems. Thisapproach has been applied to 3 models:a spinless chain, a spinless strip ofwidth 2 and the 1D Hubbard model.In the 2 spinless models, unlike thecorresponding non-interacting systemthere is a region of extended stateswhen the interactions are attractive.Repulsive interactions by contrasttend to enhance the localisation effect.For the Hubbard model there is noextended regime and in general theeffect is opposite to that of the spinlesssystems: repulsive interactions giverise to a screening effect which masksthe disorder and reduces the locali-sation. The next step will be togeneralise the approach to strips offinite cross section with a view tostudying the behaviour of 2 and 3dimensional systems using finitesize scaling.

J. B. Pendry, S. A. Ramakrishna, S. R. L. Guenneau, V. Yannopapas,W. Williams

Some time ago members of theGroup showed that a slab of materialwith the unusual property of negativerefractive index could act as a perfectlens whose resolution is unlimited bythe wavelength. Gradually the reali-sation has dawned that somethingmuch more interesting is happeningand that an alternate way of under-standing properties of a negativeslab is as a piece of negative space.Optically speaking, and only at thefrequency for which the lens conditionis satisfied, a slab of material withe® -1, m®-1 to annihilate the effectof an equal thickness of vacuum.Having realised this it is only onefurther step to prove a more general

Materials for Near Field Optics

Disordered Systems withInteractions

Spintronics

Tunnelling and Dissipation inQuantum Hall Ferromagnets

9

result: two slabs of material of equalthickness and placed adjacent to oneanother optically annihilate if one isthe negative mirror image of the other,the mirror being taken to lie on theinterface between the two slabs. Asimple instance of this is shownschematically in Fig. 1. Although thisresult is quite plausible where raysfollow a simple distorted trajectory ineach medium as illustrated above, insome instances the theorem hasstartling consequences. ConsiderFig. 2, a system drawn to my attentionby David Smith of UCSD: the mirrortheorem applies but a ray constructioncontradicts the theorem. Applying thelaws of refraction to ray 2 implies thatthe ray is rejected by the systeminstead of being transmitted throughto the other side and a dark shadowbehind the cylinders is predicted bythe ray picture. In fact a full solutionof Maxwell's equations shows thatray 2 is transmitted and emergesthrough the system just like ray 1and no shadow is formed. Theapparent paradox is resolved byrecognising that a series of resonancesform on the surfaces of the cylindersand these resonances enable radiation

to tunnel across the gap betweenthe cylinders. A clue to the nature ofthese resonances is given by theclosed loop of dotted rays in thecentre of the figure which indicatesthe presence of a state which trapsradiation i.e. we have a resonance.This elaboration of the perfect lensgreatly increases the richness of thesubject as a far greater variety of lensgeometries can now be considered.

A. Chua, C. Haselwandter, D. D. Vvedensky

Many physical phenomena can bemodelled as particles on a latticethat interact according to a set ofprescribed rules. Such systems arecalled "lattice gases".

The dynamics of lattice gases aregenerated by transition rates for siteoccupancies that are determined bythe occupancies of neighboring sitesat the preceding time step. Thisprovides the basis for a multiscaleapproach to nonequilibrium systemsin that atomistic processes areexpressed as transition rates in amaster equation, while a partialdifferential equation, derived fromthis master equation, embodies themacroscopic evolution of the coarse-grained system. Exact lattice Langevinequations for the height fluctuationsin driven lattice growth models havebeen derived from their master

equations by invoking rigoroustheorems from the theory ofstochastic processes. The equivalenceof the Langevin description and thelattice models is demonstrated bydirect comparison with kinetic MonteCarlo simulations for several standardmodels of epitaxial growth, includingthe Edwards-Wilkinson and Wolf-Villain models for surface relaxation,and models with both deposition andsurface diffusion.

C. Haselwandter, D. D. Vvedensky

Semiconductor quantum dots offerthe promise of many technologicaland scientific innovations, rangingfrom optoelectronics to quantumcomputing. All of these applicationsare based on the confinement ofcarriers within quantum dots to discreteenergy levels, as well as a degree ofspatial self-organization. The challengefor the practical implementation ofquantum dot nanostructures requiresunderstanding phenomena across arange of length and time scales. Thenucleation process, though still notcompletely understood, requires aspecific reconstruction and surfaceorientation. At a more coarse-grained level, continuum equationsthat describe the evolution of surfacemorphology abound, but none is yetcapable of making detailed quantitativepredictions on the influence of variousfactors on the ordering of quantumdots. We have derived a stochasticdifferential equations that capturesthe main effects of strain on thekinetics of quantum dot formation.It has been derived from a latticemodel that reproduces many experi-mental features. This equation canbe applied both to singular (flat)surfaces patterned substrates,where the patterning (with lithography)is used to create regular arrays ofdots. The experimental validation ofthis model will be carried out incollaboration with the group of EliKapon at EPFL in Lausanne,Switzerland.

Equations of Motion for DrivenLattice Models

Theory of Quantum Dot Formationon Singular and Patterned

Substrates

Figure 1. Above: an alternative pair ofcomplementary media, each annihilatingthe effect of the other. Light does notnecessarily follow a straight line path ineach medium, but the overall effect isas if a section of space thickness 2dwere removed from the experiment.Below: A graphical expression of our newtheorem: complementary halves sum tozero. The optical properties of the rest ofthe system can be calculated by cuttingout the media and closing the gap.

Figure 2. The left and right media in this2D system are negative mirror imagesand therefore optically annihilate oneanother. However a ray constructionappears to contradict this result.Nevertheless the theorem is correct andthe ray construction erroneous. Note theclosed loop of rays indicating thepresence of resonances.

10

Head of Group:Professor D.D.C. Bradley

Our programme of research coversmost aspects of modern experimentalsolid state physics including molecularelectronic materials, soft condensedmatter, quantum optics and photonics,magnetism, superconductivity andinorganic semiconductors. There isa strong emphasis on novel materialsand structures and on applicationsin a wide range of devices. Selectedexamples of current interests includenext generation thin film solar cells(using inorganic semiconductorquantum wells, nanostructured oxidesand organic semiconductors), opticalmicrocavities (weak and strong couplingstructures and their photonicproperties), quantum optics in solids(electromagnetically induced trans-parency and quantum light sources),ultrafast photonics for datacommuni-cations (sources, amplifiers, opticalrouters and switches), quantum dots(as novel gain media and for extendedwavelength range light emitting diodes(LEDs)), spectroscopic studies of softmatter (biomolecules, polymers),metrology for the life sciences (singlemolecule spectroscopy and micro-analysis systems), spintronic devices,High Tc and MgB2 superconductors, Si-SiGe electronics (solar cells and highspeed transistors) and molecularelectronic materials and devices (highefficiency LEDs for displays andlighting, TFTs for plastic electronics, andphotodetectors).

The group is strongly linked to theCentre for Electronic Materials andDevices (CEMD), which draws togetherpeople from the Departments ofPhysics, Chemistry, Electrical andElectronic Engineering and Materialsinto a wide range of interdisciplinaryprojects. Our activities are classified intothree main sections, namely semicon-ductor optoelectronics, molecularelectronic materials and applications,and transport and magnetism.

K. W. J. Barnham, R. Murray, G. Parry, C. C. Philips, P. Stavrinou

E. Clarke, E. Le Ru, C. Roberts, R. Murray.(P. Howe, T. S. Jones (Chemistry) )

Self-assembled quantum dots (QDs)show strong 3-D carrier confinementand are frequently referred to asÔartificial atomsÕ having discrete energylevels (see Fig. 1). They are grownby depositing InAs on GaAs, usingmolecular beam epitaxy where thelattice-mismatch-induced strain causesa 2D-3D transition into small InAsislands. Growth on GaAs, ratherthan the current standard InP, offersfinancial and technological advantages,particularly for structures that includedistributed Bragg reflectors (resonantcavity LEDs and Vertical CavitySurface Emitting lasers). After cappingwith GaAs these structures promiseimproved optical devices such as in-plane lasers, optical amplifiers andtriggered single photon sources forquantum cryptography. In addition,there is interest in coupled QDs aspotential solid state ÔqubitsÕ forquantum computing applications.

One aim is to produce in-plane andvertical cavity lasers operating attelecommunications wavelengthsaround 1.3 Ð 1.55 microns. Devicesoperating at the shorter end of thisrange may be made using a very lowInAs growth rate. Extending this tolonger wavelengths is more difficultand the method we have developed(and patented) uses an underlyingstrain-reducing seed layer. Figure 1shows that the E0 emission is nowclose to the upper limit of the requiredrange.

A second interest concerns ÔsinglephotonÕ sources for secure quantumcryptography. It is impossible togenerate single photons using weakpulses from laser beams since thephoton number obeys Poisson statistics.The unique electronic structure of theQDs ensures that the last electron-hole to recombine within the dot emitsonly one photon (confirmed via photonpair correlation experiments). Howevera single dot has to be excited andthe emitted single photons detected(see Fig. 1). This again requiresprecision engineering of the dotproperties (density, size, compositionand strain-state) and the use ofsophisticated near field opticalspectroscopy techniques (micro PL).

Experimental Solid State Physics, Centre for Electronic Materials and Devices, and Centre for High Temperature Superconductivity

Figure 1(a): Emission spectrum of a seeded QD layer. The QD ground (s) state isdenoted E0 and the excited states (p) E1 and (d) E2. The spectral width is due tovariations in dot size and composition. The inset shows a scanning tunneling micro-graph of a QD layer prior to capping. (b): Micro-PL spectra from a nominally 1 µmdiameter mesa. Individual emission lines are resolved but they probably arise from anumber of quantum dots. (Spectrum courtesy of Martin Ward, Toshiba ResearchEurope Ltd)

http://www.imperial.ac.uk/research/exss

Semiconductor Optoelectronics

Quantum Dots

(a)

(b)

11

K. W. J. Barnham, I. M. Ballard, A. Bessiere, A. J. Chatten, M. Mazzer,J. Zhang

The worldÕs highest efficiency solarcells are monolithic tandem structuresformed of GaInP and GaAs and theirperformance is limited by currentgeneration in the lower band-gapGaAs cell. Our novel strain-balanced,quantum well solar cells (SB-QWSC)extend the absorption wavelength,allowing significant current enhancementwhile preserving good voltageperformance. If our SB-QWSC wereto replace the standard GaAs cell itwould increase the tandem efficiencyfrom 34% to 37% at Å 300 sunsconcentration. Tandem cells arealready deployed on satellites butcosts must be reduced using relativelycheap light concentrating systemsbefore they can enter the terrestrialsolar cell market. We plan to optimiseour SB-QWSC within a tandemstructure grown by MOVPE (EPSRCIII-V Facility, Sheffield). The highefficiency could be exploited in novel,building integrated, concentratorsystems being developed in anindustrial collaboration. We haveextended our fundamental work onthe quasi-Fermi level separation inSB-QWSCs to the light-biasedsituation: This has important implica-tions for ultimate cell efficiency.

A novel, non-tracking concentrator,which uses the luminescence andquantum confinement properties ofQD semiconductors is under devel-opment. We have established athermodynamic model to maximiseperformance and have shown thatthe separation between luminescenceand absorption can be optimised byvarying the spread of quantum dotsizes. Finally, in collaboration withBP Solar we have studied epitaxiallygrown films of Si to investigate theultimate efficiency achievable by thinfilm Si cells.

S. Klengel, P. Caillaud, C. Palmer, P. N. Stavrinou, J. Heffernan (SLE),G. Parry

We have a strong interest in the useof sub-wavelength structures inoptoelectronic environments. Thestructures currently under investigationinvolve Photonic Crystal (PhC) patternsin III-V semiconductor materials andmore recently, the use of metallicstructures. The dispersion character-istics in these fascinating materialscan be used to control the propagationof very short pulses (fs) throughphotonic circuits. This work is part ofthe EPSRC funded Ultra-fast PhotonicsCollaboration (UPC), involving StAndrews, Bristol, Cambridge, Glasgowand Heriot-Watt Universities, andseveral industry partners. Our effortscover both theoretical modeling, andfabrication and optical assessmentof PhC structures.

High quality PhC structures have beenfabricated at Sharp Laboratories ofEurope (SLE) Ltd. A typical structure(Fig. 2 (a)) is a 4.5µm ridge waveguidewith local PhC patterns comprisingholes of diameter 240 nm and ~1 µmdepth, with lattice spacing of 420 nm.Optical characterisation of the samplesinvolves recording the full scatteringproperties of the structure, i.e. trans-

mission, reflection and verticalscattering to provide an unambiguousverification of PhC effects. Of especialinterest are the intrinsic losses of 2DPhC patterning (i.e. out-of-planescattering) and the establishment ofdesign techniques to reduce them.

Theoretical studies have establishedsuitable measures against which theperformance and properties of astructure may be assessed. Todemonstrate some of our techniquesand capabilities we have recentlyexamined the short pulse (100 fs to10 ps) transmission properties of azero-order 2-D metallic gratingwhere the slits are seven timessmaller than the incidentwavelength. Significant trans-mission is possible in the narrowwavelength regions where thesurface plasmon polariton (SPP)and waveguide mode resonancesboth occur. We showed that signif-icant pulse delays can be achieved,e.g. 250 fs delay for a pulse width of200 fs at the SPP resonance. Inaddition, the distance over which thetime delay develops is much larger(ten times) than the actual longitu-dinal dimension of the gratingstructure and coincides with thedistance over which the storedenergy and the vortices of thePoynting vector extend (Fig. 2(b)).

Sub-wavelength Technologies forOptoelectronic Components

Novel Photovoltaic Structures

Figure 2 (a): Passive GaAs/AlGaAs ridge waveguide with five rows of a 2D photoniccrystal pattern. Holes have diameter 240 nm and depth 900 nm which penetratethrough the entire guiding region (see inset). In transmission the structure suppresses TMpolarisation (wrt TE) by 20 dB over the wavelength range 1.52 - 1.64 µm. (b): Pulsedelay for the SPP resonance as a function of distance beyond the grating along withthe variation in stored energy density at the SPP resonance. Solid lines: Absolutevalues of delay for several pulse widths. Dashed-dot line: The steady state storedenergy density evaluated at the SPP resonance and averaged over a grating period.

(a) (b)

12

J. Dynes, M. Frogley, A. Green, H. Zervos, C. C. Phillips

Intersubband transitions (ISBTs) occurbetween electrons confined in a semi-conductor sample that is so small thatthe electron motion has been quantizedin one or more dimensions. They givestrongly peaked absorption spectra(which are rare in a solid) and behaveessentially as "designer atoms".Because the wavefunctions, energiesand symmetries of ISBTs can becontrolled with great flexibility, theyhave substantial scientific andtechnological potential.

Figure 3 shows the results of a quantumoptical effect, arising from ISBTs, in aquantum well sample, which have been"dressed" with a laser pulse at onewavelength (124 meV photon energy),making the material transparent at acompletely different one (the notch inthe blue curve at 183 meV). If circularlypolarized light is used, the strong ISBTabsorption allows the spin quantumnumber of these electrons to beaccessed optically. Placing the quantumwell inside an optical micro-cavity thenprovides a versatile and practical meansof combining cavity QED phenomenawith the manufactuability and relia-bility of solid state devices.

As an application example, we can usea "Quantum Cascade" diode laser,which operates with ISBTs, to makea simple 2-terminal device that willswitch optical data from one wavelengthto another. This is a critical requirementfor all-optical data switching androuting and is attracting strongindustrial interest.

D. D. C. Bradley, A. J. Campbell, L. F. Cohen, P. G. Etchegoin, J. Nelson,P. N.Stavrinou

G. Heliotis, R. Xia, M. Ramon, M. Campoy-Quilles, M. Pintani, M. Ariu, D. D. C. Bradley

Semiconducting (conjugated) polymersare an exciting new materials classfor use in electronics and optoelec-tronics. In addition to many otherapplications, including full colour flatpanel displays, there is strong interestin their potential as optical gain mediafor lasers and optical amplifiers. Animportant future target is the realisationof an electrically pumped polymersolid-state laser diode. Our programmefocusses on (i) detailed characterisation

of optical gain and loss propertiesfor polymers with emission in therange 400 - 800 nm and (ii) fabricationand characterisation of lasers basedthereon (Fig. 4).

J. Nelson, D. Poplavskyy, R. Rawcliffe,A.J. Campbell, R.U.A. Khan, D. D. C. Bradley

Fundamental research on themechanisms of charge transport inorganic semiconductors and thenature of contacts with metallicelectrodes is essential to understandthe behaviour of a variety of devices.Charge transport occurs by hoppingbetween molecular sites in anenergetically and spatially disorderedlandscape within which charge trappingmay occur at interfaces, defects,impurities, or simply at the extremesof the density of states distribution.

Molecular Electronic Materials andApplications



Polymer Gain Media for OpticalAmplifiers and lasers

Organic Semiconductor DevicePhysics

Quantum Optics ÒQubitsÓ andOptical Devices Based onIntersubband Transitions

Figure 3: Electromagnetically inducedtransparency in a quantum well ISBTabsorption spectrum.

Figure 4: (a) Spectral characteristics (absorption, photoluminescence and amplifiedspontaneous emission) of four polyfluorene polymers provided by the Dow ChemicalCompany (USA) that we have been studying as optical gain media. The emissionfrom these materials allows access to the full visible spectrum (400-800 nm). (b) Typical 2-D "egg-box", 2nd order DFB laser grating (blue arrows indicate in-planefeedback and normal to plane outcoupling directions): Grating period L = 267 nm anddepth = 30 nm. (c) The grating substrate was over-coated with a blue light emittingpolymer, PFO film (dpolymer = 200 nm) to form a laser with state of the art perfor-mance. The laser emission was at 449 nm with a 7.8% slope efficiency and athreshold energy Eth = 0.8 nJ. (d) The emission beam was nearly diffraction limitedwith annular cross-section (central image) and azimuthal polarisation (peripheralimages viewed through a linear polariser with axis shown by white arrows). Thiswork was undertaken within the Ultrafast Photonics Collaboration.

(a)

(c) (d)

(b)

13

We have a strong experimental andtheoretical effort in this area.Experimental techniques includetime-of-flight photocurrent andtransient dark injection mobilitymeasurements, current-voltage andimpedance measurements, andelectroabsorption spectroscopy,whilst theoretical techniques includeMonte Carlo simulations of transportand recombination. One recentexample of our work concerns darkinjection experiments. We have shownthat this method can be used toaccurately measure the hole mobilityin very thin films and that in materialswhere hole transport is non-dispersive,the mobility is independent of filmthickness. This result is an importantvalidation of the relevance of time-of-flight measurements on thicker(~1 µm) films, to photovoltaic andlight emitting applications, wheredevice thicknesses are typically 100nm. A second example concerns theability to achieve an ohmic contactwith standard anode materials, a keyrequirement for both light-emittingdevices and solar cells. This usuallyrequires that the anode work functionand polymer ionization potential bewithin 0.3 eV or less. We have,however, achieved ohmic holeinjection even when DE ³ 0.6 eV, bymeans of an electrical conditioningstep that modifies the interface. Wehave also evaluated a range of self-assembled monolayers of moleculeswith permanent dipole moments, asa simple means to raise the anodework function.

Semiconducting polymer field-effecttransistors (FETs) are a third example.Within the rapidly developing organicelectronics field, polymer FETs havepotential for use in a wide range ofapplications including radio-frequencyidentity tags, drivers for active matrixliquid-crystal and electrophoreticdisplays, and memory cards. Recentwork has focused on ordered materialsfor high mobility FETs, new FET gateinsulation materials, methods to lowerthe FET turn-on voltage using lowionisation potential polymers, andcomparative bulk and FET carriermobility measurements (Fig. 5).

J. Nelson, F. M. Braun, R. E. Chandler,A. J. Chatten, S. A. Choulis, A. M. Eppler, Y. Kim, R. Pacios, D. Poplavskyy, P. Ravirajan, S. M. Tuladhar, D. D. C. Bradley

Solar cells based on molecularmaterials rely on charge separationat the interface between electronacceptor and electron donor materialsand 'distributed heterojunction' struc-tures where the two phases contactover a large interfacial area are highlydesirable. We are studying a range ofthese structures based on polymer/polymer, polymer/molecule andpolymer/nanoparticle blends, as well

as dye sensitised systems.

In respect of dye-sensitised solarcells (DSSCs) we have studied indetail the recombination pathwaysthat compete with photocarriercollection. An especial focus hasbeen on solid state DSSCs wherethe electrolyte is replaced by a holetransporting organic semiconductorfilm. Our findings are now beingintegrated into a device model tobetter interpret the solar cell charac-teristics. In addition, electron transportis being modeled for films of quantum-sized ZnO nanoparticles (collaborationwith Debye Institute, Utrecht). TheQDs behave like Ôsuper atomsÕ, withan electron-density dependent mobilitythat can be related to the filling ofthe quantised electronic levels. Ourmodels will help to establish theconditions under which a conducting-insulating transition should be observed.

A second research area concernsthe PV properties of TiO2 / polymernanocomposites. The polymersensitises the TiO2 film, and affordshigh optical density with muchthinner films than for solid stateDSSCs, relaxing the demands onhole transporter conductivity. Veryefficient charge separation occurs atthe TiO2 / polymer interface with afactor of five increase in photocurrentquantum efficiency by insertion of aporous layer between dense TiO2

electrode and polymer (Fig. 6).Optimisation allows quantumefficiencies of 40% and powerconversion (solar illumination)efficiencies ³ 0.6% (Fig. 6). This ismore than double reported literaturevalues and a systematic study isnow underway to understand theremaining limiting factors.

We have also undertaken a majorresearch programme (funded byBritish Petroleum) focused onunderstanding and enhancing theefficiency of organic solar cellsbased on blends of C60 fullerenederivative PCBM and several conju-gated polymers. PCBM is an effectiveelectron acceptor and efficientelectron transporter and we obtainpower conversion efficiencies ³ 3%when blended with regioregular

Figure 5: (a) Source-drain current-voltagecharacteristics of a poly(9,9-dioctylfluorene-co-dithiophene) copolymer (F8T2) FET.(b) Comparison of the hole mobilitycalculated from the FET current-voltagecharacteristics and that derived frombulk space-charge-limited current diodeand time-of-flight measurements for apoly(9,9-dioctylfluorene-co-phenylene-diamine) (PFB) copolymer. The differencesare believed to be due to the blockingbehaviour of the source electrode,suggesting that polymer FET theory mustbe adjusted to take this into account.

Dye Sensitised nanocrystallineOxide, Organic-Inorganic Hybrid

and All-Organic Solar cells

14

poly(3-hexylthiophene [P3HT] (fromthe Merck Chemical Company). Wehave characterised the key mecha-nisms of light harvesting, chargetransport and recombination in suchblends using a range of complementarytechniques: These include device (J-V and photocurrent quantum efficiency),time-of-flight and dark-injection mobility,photoluminescence quenching andelectroabsorption spectroscopymeasurements, and AFM studies offilm morphology, as well as transientoptical measurements of recombinationkinetics (with Dr James Durrant(Chemistry)). Our results show thatfilm morphology, especially in respectof the nature and length scale forphase separation, is critical to devicefunction and the performance ofP3HT:PCBM blends has beenoptimized accordinglyby solvent andannealing treatments. We have alsodeveloped a set of numerical modelsin order to interpret our experimentalmeasurements in terms of the micro-scopic transport and recombinationmechanisms, and to simulate andoptimise light harvesting in thinorganic films.

R. Maher, P.G. Etchegoin, L. F. Cohen

SERS occurs due to huge enhance-ments of the local electromagneticfield at the surface of nanostructuredmetals such as gold, silver and copperin the presence of laser excitation.The SERS spectra of any particularanalyte provide a strong chemicalsignature related to the adsorption ofthe analyte at the nanostructuredmetal surface, the details of the metal-analyte bond and also the resonantcharacteristics of the molecule itself.SERS may offer potential as anultrasensitive chemical nose (winningout over fluorescence spectroscopybecause of the vibrational informationthat it offers) but it is not yet sufficientlymature as a technology. Our work hasfocused on the fundamentals andapplications of the technique, forexample we have been investigatingthe origin of hot spots (locations thatproduce the largest enhancement).With the National Physical Laboratorywe have been addressing metrologyissues e.g. How do you comparedifferent SERS surfaces? How do youconduct experiments that are repro-ducible? As part of this activity we havestudied the ratio, r of the Anti-Stokes toStokes scattering as a function oflaser energy for the case of silver

colloids and rhodamine dye molecules.If the Raman cross-section for theStokes and Anti-Stokes signals arethe same and the number of activemolecules are known, r can beused to quantify the SERSenhancement factor. We find that ris a function of laser power andshows a threshold for stimulation.

A. D. Caplin, L. F. Cohen, J. Zhang

Y. Bugoslavsky, W. Branford, S. Clowes, L. F. Cohen, Y. Miyoshi,G. Perkins, S. Roy

We are studying a range of highlyspin polarised magnetic materialswith the aim of using them as spinelectrodes in the development ofhybrid ferromagnetic-semiconductordevices for Spintronics. The magnetotransport, Hall and Andreevspectroscopy of NiMnSb (in collabo-ration with FORTH in Heraklion, Crete)and Co2MnSi (in collaboration with theMaterials Department at CambridgeUniversity) yield information concerningthe band structure and the integrityof the transport spin polarization.These key parameters vary as afunction of composition, film thickness,grain size and strain. Understandinghow to control and optimize them iscritical to the success of deviceapplication.

In 2003 we embarked on a new area,taking advantage of the versatility ofthe scanning Hall probe for largearea imaging of magnetic materials.The work grew from collaboration withDr Roy from Indore, who workedwith us as an EPSRC Visiting Fellow.Using doped-CeFe2 alloys as"idealised" test-bed material systemswe have been able to demonstrateconclusively that two features, phase-coexistence and metastability, mustalways be present at a disorder-influenced first order transition.Through scanning Hall-probemeasurements we were able to showextremely clear visual evidence ofmagnetic phase-coexistence onmicrometer scales as the system isdriven across the entire first orderantiferromagnetic (AFM) to ferro-

Surface Enhanced RamanScattering (SERS)

Transport and Magnetism

Functional Magnetic Materials

Figure 6: (a) Device structure of hybridpolymer / TiO2 device. (b) Currentdensity vs voltage characteristics of thinand thick polymer / TiO2 multilayerdevices under simulated solar illumi-nation (100 mW cm-2).

Figure 7: Power dependence of r forthe 1560 cm-1 Raman model of RH6Gunder 633 nm illumination at 300K. Afeature resembling a threshold of stimu-lation can be seen. The value for rbased on the predicted thermal valueexp(-hwn / kBT), where wn is the frequencyof the Raman vibration is also shown.

15

magnetic (FM) transition as afunction of temperature, magneticfield and time (see Fig. 8). Thesimplicity of the CeFe2 system clarifiesthe underlying physics common tomany classes of material that wenow plan to study in particularmagnetic shape memory alloys andgiant magnetocaloric systems.

W. Branford, S. Clowes, L. F. Cohen,B. Murdin, T. Zhang

III-V Narrow gap semiconductors(NGSs) such as InAs and InSb arerecognised to offer unique functionalityfor spintronic devices (i.e. devicesthat depend on the manipulation ofspin rather than charge), because oftheir high effective g-factors, loweffective mass and large spin-orbitcoupling. Yet to date they have beenrelatively ignored compared to work onGaAs. We are involved in a Europeanwide effort to exploit these propertiesby creating hybrid NGS Ð ferromagneticmetal devices. We have made signif-icant progress towards producing high

mobility thin InSb material for hybridsensors and, using a new Imperialrecipe that minimizes dislocations,we have obtained films of uninten-tionally doped InSb on GaAs (100)with the highest room temperaturemobility reported to date.

Y. Bugoslavsky, A. D. Caplin, L. F. Cohen, Y. Miyoshi, J. Moore,G. Perkins

The simple binary compound MgB2,discovered to be super-conductingin 2001 with a Tc of 39 K, offersinteresting prospects for applications,particularly for high current conductorsand also perhaps Josephson junctiondevice electronics. Our activitiesduring 2003 have focused on thebehaviour of the two superconductinggaps in the presence of magneticfield. We have been studying thisfundamental aspect using tunnellingspectroscopy to look at how thedensity of states of quasiparticles andCooper pairs evolve as a function ofapplied dc field. There had been amisconception that the smaller gap

was quenched by low applied field,which would have catastrophic impli-cations for applications. We haveclarified the situation and demon-strated that both gaps survive to theupper critical field (Fig. 9). We arejust embarking on a major EU-fundedproject to further develop this materialfor conductors.

As well as the demand for higherspeed/lower power devices, thenewly developed concept ofÔquantum computingÕ has stimulatedmuch work aimed at the fabricationof phase coherent quantum logicstates or ÔqubitsÕ. Superconductorsprovide many possibilities due totheir fast response times, low powerdissipation levels and intrinsicmacroscopic phase coherence. Aparticularly interesting class ofdevice involves the controlledmanipulation of quantised vorticeswithin superconductors. Althoughthe applications of such deviceswould be far-reaching, the key issueis how to produce the requiredvortex control. A novel solution couldbe to use the intrinsic interactionsbetween Josephson vortices andpancake vortices that are known toco-exist in highly-anisotropic super-conductors. Based on theseconcepts, we have initiated experi-mental studies into the new area ofFlux Ratchet devices.

Growth of Narrow GapSemiconductor for Hybrid Sensor

and Spintronic Applications

Figure 8(a): M versus T for 5% Ru doped CeFe2 in an applied magnetic field of 35 kOeafter zero field cooling ZFC and field cooling FC. The AFM-FM transition region ishighlighted and representative Hall-probe images have been inserted (each framecovers an area of 1 x 1 mm). The AFM state (black) is represented by field intensityless than 20% of the saturation value while yellow regions represent intensitiesgreater than 20% of this value. At the onset of the transition FM-clusters appear atrandom positions across the sample and vary in size. The frame left of centre showsthe effect of field cycling by 5 kOe after reaching 32 K in the FC path. SupercooledFM clusters are readily destroyed by this field cycling, highlighting the metastablenature of the magnetic state. (b) Images showing temporal evolution of the phase-coexistence at 20 kOe at 60K. Two images were taken 152 minutes apart, demon-strating nucleation and growth of the FM domains.

Superconductivity: Fundamentalsand Device Concepts

Figure 9: The field dependence (D(B)) ofthe two energy gaps as determined bypoint contact spectroscopy for a MgB2film with Tc = 38K .

16

Head of Group:Professor P. J. Dornan

Members of the High Energy Groupexercise significant influence in manyof the current and future internationalexperiments that investigate thefundamental particles and the forcesbetween them. A primary aim is toaddress basic questions such as theorigin of mass and the observedasymmetry between matter and anti-matter. Much of the programme isdirected at discovering where theStandard Model, that has provedamazingly successful in the descriptionof electro-weak interactions, will breakdown, since theoretical expectationsimply that it cannot be the final story.This will be accomplished by testingpredictions to high accuracy andlooking for phenomena outside themodel such as supersymmetry anddark matter.

T. Virdee, G. Hall, C. Foudas, D. Britton, M. Raymond, C. Seez, J. Fulcher, G. Iles, A. Nikitenko, M. Ryan, R.Bainbridge, D. Colling, B. MacEvoy, H. Tallini

The Large Hadron Collider (LHC), is anew CERN accelerator underconstruction due to begin operation in2007. It will collide protons at centre ofmass energy of 14 TeV and will be thehighest energy machine in the world,opening a new window of discoveriesin particle physics. In particular, it isexpected that the elusive Higgs boson,which is the means by which quarksand leptons in the Standard Modelobtain their masses, will be identified.

The CMS (Compact Muon Solenoid)experiment, part of which is shown inFig. 1, is a general purpose detectorbeing constructed at LHC. ImperialCollege has major roles in detectordesign, construction and the scientificproject management. The group isactive in the electromagneticcalorimeter (ECAL), the chargedparticle tracking system and isdeveloping software for detectorreadout and data analysis.

In the ECAL, electron and photonenergies are measured by theirinteractions in lead tungstate crystalsread out by avalanche photodiodesor vacuum phototriodes. We havebeen making precise measurementsof the uniformity of the light collectionalong the length of the crystals using

a hybrid photomultiplier device. A newamplifier for the ECAL readoutsystem was developed at Imperialover the last year.

The CMS tracker is a very largesilicon detector system, which is anarea where Imperial has two decadesof expertise. Charged particle momentaare measured by bending in the 4Tmagnetic field, using finely segmentedmicrostrip detectors read out with lownoise, radiation hard CMOS chips(APV25) developed by ImperialCollege and Rutherford Laboratory,who are responsible for much of theelectronic readout system.

An example of the type of discoverywhich CMS could make, other thanthe Higgs, is the search for evidenceof extra spatial dimensions. TheRandall Sundrum model postulatesa 5D universe with two 4D surfaces(ÒbranesÓ). Fluctuations of the metricin the fifth dimension are described interms of a scalar field, the radion (f),which can mix with the Higgs boson (h).This scalar sector of the model isparametrized in terms of Higgs andradion masses mh, mf, a dimen-sionless parameter, x, and the

High Energy Physics

Figure 2: The di-photon (a), di-jet (b) and radion (c) reconstructed masses after allselections; (d) the 5s discovery contour in the (x-Lf) plane with 30 fb-1.

CMS

Figure 1: The first section of the CMSsolenoidal superconducting magnet coil.Behind it is the Forward HadronCalorimeter (silver) and sections of themagnet iron yoke (red).

http://www.imperial.ac.uk/research/hep

17

vacuum expectation value of theradion field, Lf.

In certain regions of parameter spaceCMS could observe the radion viaf ® hh when one Higgs boson decaysinto two photons and the other decaysinto a b-quark pair. As an example,the discovery reach in the plane of xand Lf, was evaluated for 30 fb-1 ofdata assuming mf = 300 GeV/c2 andmh =125 GeV/c2. In this region of mfand mh, f ®hh discovery willcomplement observation of a reducedf ® ZZ* rate compared to the StandardModel, confirming the nature of theobserved intermediate-mass scalar.Event selections, in addition to thoseused for the h ® gg search, includethe requirement to find two jets in theevent with at least one of them taggedas a b jet. Fig. 2(a) and (b) show di-photon and the di-jet invariant massesafter all selections for the backgroundand for the signal at the maximalsignal cross section point with 30 fb-1.Fig. 2(c) shows the reconstructedmass of the radion after cuts on thedi-photon and the di-jet masses. The5s contour in the (x-Lf) plane is inFig. 2(d).

R. Beuselinck, G.J. Davies, A. Goussiou, J. Hassard, J. Hays,R. Jesik, P. Jonsson

The Tevatron, at Fermilab, near Chicagois the worldÕs highest energy particleaccelerator, colliding together protonsand anti-protons at close to 2 TeV,putting it at the very forefront ofdiscovery.

At a hadron collider the trigger (real-time selection of wanted events) iscritical due to the very large QCDbackground. The highest level triggerat DÆ, Level-3, performs a partialreconstruction of the event (in ~100 ms)so placing it at the boundary betweentrigger and physics. The Imperial groupis the largest single group at Level-3.Current activities include overall co-ordination and the development oftrack (and track based) triggers,including Ôb-taggingÕ algorithms, usedto identify jets containing b-quarks.The output of such a tool is shown inFig. 3; the signed Ôimpact parameterÕ

from a recent run is displayed, showinga positive excess, indicating that b-quarks are present in the sample.Another critical area is the under-standing of the energy scale of thejets of particles produced after theproton anti-proton collision, and theoptimisation of the jet mass resolution.

Two of the main physics areas inRun II are B-physics and the searchfor the Higgs boson Ð the elusiveparticle that is responsible for givingmass to all we see around us. TheTevatron produces some trillion Bmesons per year allowing us to studyCP violation, rare decays and theway b and anti-b quarks mix. Wehave already produced significantresults, including B-lifetimes; effort isnow focused on B-mixing.

Activity is also already well underwayfor the longer term goal of finding theHiggs. Within two years we will beable to answer whether LEP did seethe first hints for a Higgs at around115GeV. Increasing effort is going intoSUSY Higgs searches, which relyheavily on b-tagging at the trigger level.

W. Bhimji, D. Bowerman, P. D. Dauncey, U. Egede, I. Eschrich,J. Martyniak, G. Morton, J. A. Nash,D. J. Price

The BaBar detector is located at thePEP-II electron-positron collider atthe SLAC laboratory in California.The BaBar collaboration is studyingCP violation using B mesons. In 2001it made the worldÕs first observationof this phenomenon in B decaysthrough the measurement of theparameter sin2b of the CKM matrix.This parameter is indicative of ÒindirectÓ

CP violation. Since then, usingincreased statistics, this measurementhas been improved to better than10% precision.

The Group is heavily involved instudies of CP violation in charmlesshadronic B decays. These decaysare sensitive to different CKMparameters, namely sin2a and g, andthey should exhibit the ÒdirectÓ typeof CP violation. This is expected to berare and has not yet been observedin B decays; a significant observationwould be very important and is themajor goal of this study. An exampleof a computer reconstruction of acharmless B decay observed in theBaBar detector is shown in Fig. 4.

W. Cameron, P. Dornan, U. Egede, A. Howard, D. Price, D. Websdale,R. White

The LHCb experiment is specificallydesigned to study B-mesons to theultimate precision. The aim is toprovide measurements of CP-violation with the highest sensitivityand to look for new physics beyondthe Standard Model.

For the CP-violation studies particleidentification is required to identifythe flavour of the quarks participatingin the B-decay. Particles of a knownmomentum travelling through amedium with velocity greater than thespeed of light in the medium emit

D0 at the Tevatron

BaBar

Figure 3: Signed impact parameter froma recent run, showing an excess ofpositive lifetime events.

Figure 4: An example of a B decaycandidate in the channel KKKS asobserved in the BaBar detector. The thinblue lines show the reconstructedcharged particle trajectories, the greenblocks indicate electromagnetic energyin the calorimeter, the pink dots showdetected Cherenkov light which is usedto identify the type of particles and thelarge blue blocks indicate hits in theouter flux return chambers.

LHCb

18

photons at a fixed angle dependingupon the mass of the particle. Byimaging the emitted photons onto aplane they will form rings where theradius identifies the mass of theparticle. In LHCb this is done with twoRing Imaging Cherenkov Detectors,RICH1 and RICH2.

To improve the projected performanceof LHCb the experiment design wentthrough a substantial re-optimizationof its tracking and magnetic fieldconfiguration. This work was success-fully finished in 2003 and the newexperiment design can be seen inFig. 5. The implications for the RICH1detector were large and the ImperialGroup is responsible for turning theredesign into a full design that satisfiesdemanding criteria.

C. Foudas, A. Jamdagni, K. Long,A.Tapper

The HERA collider in Hamburg is amicroscope used by the ZEUScollaboration to look deep inside theproton. A 27.5 GeV electron collideswith one of the quarks inside a 920GeV proton, splitting the proton andthrowing out debris that can bedetected. The proton structure isstudied together with the nature ofthe strong force. The Group hasprovided key pieces of ZEUS, whichit helps run and maintain.

From summer 2003 HERA has beenrunning with high intensity polarisedpositron beams. This has allowed usto make the first ever measurementsof the polarisation dependence ofthe charged current cross sections.We plan also to measure the polari-sation dependence of the neutralcurrent cross section and to use these

measurements to search for physicsnot described by the SM. Crucial tothis programme is a precise measure-ment of the lepton beam polarisation.IC physicists have taken the lead inthe development of a position detectorthat will allow the required precisionto be obtained.

E. McKigney, M. Ellis, A. Jamdagni,K. Long, P. J. Dornan, W. G. Jones

The discovery of neutrinos changingfrom one type to another as they travelthrough space (Ôneutrino oscillationsÕ)implies that neutrinos are massive,that the Standard Model is incompleteand makes the neutrino sector theonly presently accessible window onphysics beyond the Standard Model.The small, but non-zero, neutrino masshas astrophysical consequences. Inparticular, the interactions of theneutrinos may underpin the mechanismby which antimatter was removed fromthe early universe. The far-reachingconsequences of neutrino oscillationsjustify a dedicated experimentalprogramme. The worldwide consensusis that a Neutrino Factory Ð an intensehigh-energy neutrino source derivedfrom the decay of a stored muon beamÐ is the ultimate tool for the study ofneutrino oscillations.

We have begun an ambitiousprogramme of R&D aimed at devel-oping a conceptual design for theNeutrino Factory. To reach the requiredstored muon intensity requires thatthe size and divergence of the muonbeam be reduced or ÔcooledÕ. Thetechnique that has been proposed todo this involves passing the muonbeam through liquid hydrogen, whichreduces the beam energy, and thenreaccelerating the beam. Thissequence of operations cools thebeam and is referred to as ÔionisationcoolingÕ. In order to demonstrate thefeasibility of ionisation cooling, weare mounting the Muon IonisationCooling Experiment (MICE). Weproposed the scintillating fibre trackerthat forms the baseline instrumentationfor the MICE spectrometers. Overthe past year we successfully built aprototype tracker which is shown inFigure 6.

A crucial input to the MICE experimentis the precise measurement of thescattering distributions of muons asthey pass through matter. We haveplayed a leading role in the MuScatexperiment that will measure thesedistributions.

Over the coming year we plan toexpand out activities in the NeutrinoFactory area. We have forged aclose collaboration with CCRLCÕsRutherford Appleton Laboratory tostudy the conceptual design of theaccelerator complex and to developaccelerator structures for the high-power pulsed proton injector.

D. Bowerman, W. Cameron, P. D.Dauncey, D. J. Price, O.Zorba

There is a large worldwide effortworking towards a high energy electron-positron linear collider with a centre ofmass energy in the range 500-1000GeV. Such a linear collider wouldallow precision measurements of anyHiggs (or SUSY) particles in this massrange as well as having a significantdiscovery potential of its own.

To fulfill the physics potential of thismachine, the calorimetry for a detectorat the linear collider needs to beable to reconstruct jet energies withresolutions exceeding anythingpreviously achieved. The Calicecollaboration has been formed tostudy both electromagnetic andhadronic calorimetry for a linearcollider detector. The Imperial grouphas led the design of the readoutelectronics for a prototype high-granularity electromagneticcalorimeter within this collaboration.

Figure 5: The layout of the redesignedLHCb experiment. The main involvementfor Imperial is the design and constructionof the RICH1 detector.

ZEUS

Calice

Neutrino Experiments

Figure 6: Prototype scintillating fibretracker prior to installation in aluminiumsupport tube.

19

Director:Professor J. P. Marangos

The Blackett Laboratory LaserConsortium researches new frontiersof science made possible by high powerultra-short laser pulses. This excitingarea of science includes new develop-ments in ultra-fast measurement,generation and applications ofattosecond duration light pulses,controlling quantum processes inmolecules, producing bright sourcesof radiation in the X-ray region andcreating high energy density plasmas.We operate three high power lasers;a high energy sub-picosecond glasssystem and two titanium:sapphiresystems; one delivering up to 100 mJin a 50 fs pulse at a 10 Hz repetitionrate, and a second 1 kHz repetitionrate system with 30 fs duration ~1 mJpulses. Using these lasers and throughour accompanying theoretical workwe are making pioneering contributionsto the fields of ultra-short pulsegeneration, non-linear optics, plasmaphysics, and molecular dynamics.We are funded with support from theEPSRC/MOD, the Basic TechnologyProgramme of the RCUK and throughvarious grants from the EU and theRoyal Society. There are activecollaborations with other leadinggroups in Europe and North America.The Blackett Laboratory LaserConsortium forms part of the QuantumOptics and Laser Science Group.

Forest fires and cluster ionisation instrong fields.P. L. Knight, L. Gaier, L. Chipperfield.

In a collaboration with the group ofPaul Corkum at NRC Ottowa, weinvestigated the ionisation of clustersby short, intense laser pulses.Traditionally, the dynamics of laser-induced breakdown is divided intoseveral stages. First, conventionalmultiphoton ionisation provides aseed population of free electrons.Second, these electrons take energyfrom the field through laser-assistedcollisions. Third, when the electronenergy exceeds the bandgap, electrons

are promoted into the conductionband. Clearly, this picture shouldchange when dealing with extremelyshort - few cycle laser pulses: atsome point the pulse duration shouldbecome too short to enable significantheating of the electrons in theconduction band. Where this boundarylies depends on the laser wavelength,intensity, bandgap, etc. Very largeatomic clusters are similar todielectrics for short laser pulses, aslong as the expansion of the clusteris negligible during the pulse.Mechanisms of damage in dielectricsare thus similar to ultrafast clusterionisation, and act at very early time.They are complimentary to theionisation and absorption mechanismsinduced by the cluster expansion.

We have concentrated on one suchdamage mechanism which becomesoperative when the laser pulses aretoo short (and the intensities and/orenergies too low) to induce traditionalavalanche ionisation. Mathematically,this mechanism can be described asthe propagation of Òforest firesÓ. Thecore effect responsible for laser-induced Òforest firesÓ in clusters anddielectrics is known as ÒenhancedionisationÓ in molecules and ÒionisationignitionÓ in clusters. When electronslocalise on the nuclei (e.g. duringdissociation of a molecule, or in arare gas cluster), removal of suchan electron leaves an uncompen-sated positive charge - a hole. Wedescribe the dynamics of ultrafastdamage in dielectric materialsirradiated by light below the conven-tional breakdown threshold. Thedamage occurs on a sub-laser-wavelength scale. It starts with theformation of nano-droplets of plasmawhich grow like forest fires, withoutany need for heating of the electronspromoted to the conduction band.The dimensionality of the damagedarea can be fractal and changesduring the laser pulse. This mechanismis operative in both rare gas clustersand dielectrics interacting with ultra-short, moderately intense laser pulseswhich include only a few periods ofthe driving field, too fast for traditional

avalanche mechanisms.

Modelling of Few-cycle OPCPAlasers, G. H. C. New.

Chirped Pulse Amplification (CPA) isan elegant solution to the problem ofnon-linear optical damage in highpower lasers. However current CPAlasers are limited to durations > 25 fsby the finite gain bandwidth ofmaterials such as Ti:sapphire.Optical parametric chirped pulseamplification (OPCPA) has advantagesover ÒtraditionalÓ gain media in termsof both bandwidth and amplifiedspontaneous emission (ASE).OPCPA uses non-linear opticalprocesses to transfer energy from apump to a seed pulse in a singlepass through a non-linear crystal.This provides up to 5x the bandwidthof Ti:sapphire, single pass gainsapproaching 105 and greatlyreduced ASE.

A split-step code has been developedin collaboration with Ian Ross (RAL)that solves the coupled wave equationswith dispersion to all orders. Thecode allows for three OPCPA stages,

Strong Field Theory

Laser Consortium http://www.qols.ph.imperial.ac.uk/consort/

Figure 1: Numerical modelling of electrondynamics driven by a single cycle pulse.

Laser Development and modellingLaser Development and modelling

20

and can handle a dynamic rangebetween uncompressed andcompressed pulse widths of > 105.It incorporates stochastic featuresincluding non-transform limitedpulses and random noise. Usingthis code we have studied a rangeof OPCPA designs to guided theconstruction of a new laser systemable to deliver a sub-10 fs pulses atan energy of >10 mJ and focusedintensities >1018 Wcm-2.

J. P. Marangos, R. A. Smith, J. W. G. Tisch, K. Mendham, J. Robinson, A. Moore.

The frequency components of anoptical pulse can be dispersed andrecombined in a so called ÒnullstretcherÓ. By placing a modulatorin the Fourier plane of the stretcherthese wavelengths can be individuallymanipulated, allowing detailed controlof the temporal shape of a high powerlaser pulse. We have recentlyimplemented such Òpulse tailoringÓ onour high power Ti:Sapphire lasersystem using a multi-element LCDarray. This allows us to created pulseswith variable duration, chirp andtemporal structure. The pulse shaperis coupled to a Genetic Algorithmthrough a feedback loop allowingthe laser to ÒlearnÓ about and optimiseexperiments in situations where theÒbestÓ laser pulse is unknown.Diagnostics such as a FrequencyResolved Optical Gating Spectrometer(FROG) then allow us to determinethe pulse shape found experimentally.We have recently used this techniqueto optimise x-ray emission from acluster gas (Figure 2).

J. W. G. Tisch, J. P. Marangos,R. A. Smith, J. Robinson, C. Haworth, P. Bates.

September 2003 saw the start of asubstantial new project to produce,characterise and apply attosecond-duration light pulses (an attosecondis 10-18 s). Funded by the ResearchCouncils UK through the BasicTechnology Programme, this is acollaborative project centred andmanaged within the LaserConsortium, involving Birmingham,Oxford, and Reading universities,UCL, and the CCLF at RAL.

The attosecond source at ImperialCollege is based on non-linearfrequency conversion of intense(~1015 Wcm-2) ultra-fast (~6 fs) near-IRlight pulses in gaseous media throughhigh harmonic generation.

Attosecond XUV bursts of light areproduced as electrons in the mediumare first dragged away from their ioncores, accelerated in the stronglaser field to around 100 eV, andthen half a cycle later make single,

energetic collisions with their cores.

Important steps towards theproduction of the intense, few-cyclepulses required have already beentaken in a new SRIF refurbishedLaboratory. We use a gas-filledhollow waveguide in whichfemtosecond laser pulses arespectrally broadened by SPM andrecompressed using chirped mirrorsto the few-cycle limit. By coupling0.6 mJ, 25 fs pulses centred at 800 nmfrom a commercial, kHz laser into a1 m long gas-filled 250 mm diameterhollow fibre (shown in Fig. 3) wehave demonstrated the necessaryspectral broadening to support few-cycle pulses. Bandwidths > 300 nmhave been demonstrated (see Fig. 4)at input intensities of » 1014 Wcm-2

with energy transmission > 60% andan extremely high quality guidedmode. Work is now underway tocompress these pulses to < 6 fs.

Related developments to producehigh power sub-femtosecond pulses

Shaping of High Intensity LaserPulses

Laser Development and modellingAttosecond Project

Figure 2: FROG Image of a double pulseevolved using the genetic algorithm tooptimise the soft x-ray yield from Xeclusters.

Figure 3: Gas-filled hollow fibre used tospectrally broaden fs pulses.

Figure 4: Spectra of pulses from thehollow fibre. Black curve is with fibreevacuated (essentially the input laserspectrum); the red curve is with 2 bar ofArgon in the fibre.

Figure 5: The grey spectra shows theadvantage of driving with two Ramanresonant fields. Insert:. Calculatedtemporal profile of the pulse that couldbe synthesized from this spectrum.

21

have been made using high orderRaman side band generation. Inthese experiments high pressuremolecular gases confined in ahollow fibre are driven by a pair of100 fs laser pulses tuned to Ramanresonance. The result is very efficienthigh order side band generationproducing bandwidths able to supportpulses under 1 fs (see Fig. 5).

J. P. Marangos, E. Springate,R. DeNalda, E. Heesel, N. Kajumba.

We have used techniques pioneeredat Imperial to study strong field inter-actions with controllably alignedmolecules. A 300 ps pulse from theTi:S CPA laser was used to performnon-resonant adiabatic alignment inrotationally cooled (Trot~20K)molecules (e.g. CS2, CO2). Thesealigned molecules were then exposedto intense 70 fs pulses focused to »1014 Wcm-2 and the dependence ofHHG (high harmonic generation)studied. The origin of alignmenteffects on HHG has been found toarise through anisotropy in the phaseand amplitude of the harmonic dipole,a feature unique to molecules.

We have examined the dependenceof HHG yield upon the angle betweenthe molecular axis and laser polari-sation. Recent data (15th harmonicfrom aligned CO2) illustrating this isshown in Fig. 6. Harmonic emissionis found to be lower in CO2 moleculesaligned parallel or perpendicular to thelaser field direction and to be largerfor intermediate angles. This hasbeen well reproduced in calculationsthat take into account the anti-symmetric orbital symmetry of the

relevant electronic states in themolecule. This indicates that quantummechanical destructive interferencebetween regions of the originalwavefunction that have different signleads to suppression of HHG.

More recently we have begun exper-iments that move beyond the adiabaticalignment process and employimpulsive alignment, giving strongalignment under field free conditions.An example of a rotational revivalmeasured using an optical probe isillustrated in Fig. 7. This method isnow being applied to the study ofaligned molecules in intense fields.

R. A. Smith, J. W. G. Tisch, J. Marangos, D. Symes, E. Springate,A. Moore J. Robinson, J. Lazarus.

Optimisation of the yield of soft x-rayemission from laser irradiated 350,000atom cluster targets between 10-400 eV was investigated using high-power pulse tailoring. Our Ti:Sapphirelaser was coupled to a pulse shaperto produce 10 mJ, 90 fs pulses whichwere focussed into a cluster jet.The x-ray yield from the clusters wasthen fed back to a genetic algorithmcontrolling the pulse shaper.

The algorithm searched for optimumx-ray generation by evolving thepulse into a multi-bunch structure asshown in Fig. 2. Figure 8 shows afitness curve for a ten generationevolution experiment demonstratingan improvement of more than 100%.

We have also continued our work onshaped blastwaves produced inlaser machined cluster media.Atomic clusters are extremely efficientabsorbers of intense laser light andwe use them to create ultra-highenergy density ( >5x105 J/cc)plasmas. Energy initially depositedby the laser in a narrow 20 mmcylinder propagates outwards as aMach 40 shockwave, heating andionising the surrounding coldmaterial. Figure 9 shows experi-mentally measured blastwave radiifor a range of cluster gasses, fromwhich we determine the ÒdecelerationparameterÓ that characterises theblastwave evolution.

Molecules in strong fields

High intensity laser interactions withnanoparticles

Figure 6. Dependence of HHG yield on theangle between E-field and molecular axis.

Figure 7: A rotational revival in impulsivelyaligned CO2 measured using polarisationrotation.

Figure 8. Evolutionary ÒFitness curveÓfor large laser irradiated Xe clustersshowing more than 100% improvementin absolute x-ray yield.

Figure 9. Blast wave radius as afunction of time for laser irradiated H, Arand Xe cluster plasmas showing nonSedov-Taylor behaviour.

22

Head of Group:Professor P. M.W. French

The broad themes of research areimaging and sensor technology,fibre and laser optics and biopho-tonics. Current projects includeadaptive optics applied to astronomyand medical (ophthalmic) imaging;biomedical optics, including high-speed 3-D imaging and fluores-cence lifetime imaging applied totissue diagnosis and molecular biology;rigorous electromagnetic theory (FE,FDTD, volume integral methods),applied to focusing, imaging andpolarisation, chiral media and Braggstructures; high power fibre lasertechnology, including telecommuni-cations amplifiers and sources,nonlinear fibre optics and compacthigh power visible/UV sources; opticalfibre sensors, high power solid-statelaser technology and nonlinear optics;ultrafast diode-pumped solid-stateand fibre laser technology and opticalstorage, including DVD, multiplexedhigh density storage.

A representative selection of topicsis given below:

S. Popov, J. R. Taylor

Our research, which builds on highpower fibre amplifier technology andour continued interaction with IPGPhotonics, the world leader in thistechnology, continues to emphasiseapplications outside telecommunica-tions. We have developed a novelself-starting source of ultrashort pulses,which exploits polarization and spectralshaping, together with high singlepass gain, in normally dispersive,Yb-doped fibre lasers to provide pulsesof durations selectable in the range of1-20 ps. Emphasis has been placedupon schemes. In a cooperativeresearch programme with IPG thesepulses have been amplified to peakpowers of 60kW at an average powerof 9W.In the past year, considerable researcheffort has been directed towards fullyfibre integrated chirp pulse amplifiers

using air-cored photonic band gapfibre, where the air core reduces theeffect of non linearity and the spectrallyselective transmission characteristic ofthe band gap adjusts the overalldispersion to be anomalous in specificspectral regions. As a consequence,we have demonstrated the worldÕsfirst all fibre chirp pulse amplifier,achieving peak powers of 20 kW atmulti-watt average powers. Pulsecompression up to 100 times has beenachieved in all fibre configurationswith chirped pulses amplification inYb, Yb:Er and (at unrestrictedwavelengths) Raman fibre amplifiers.

Exploiting our capability of low losssplicing of photonic crystal fibres toconventional fibres, we have developedlow maintenance broadband continuumsources under c.w. operation utilizingboth conventional highly nonlinearfibre and holey fibre. In conventionalfibre, a flat spectral continuumextending from 1.5-2.1 mm wasachieved, with less than 1 dB peakto peak ripple and a spectral powerdensity of 16 mW/nm. In holey fibre,pumped at 1 mm, a >5W c.w.continuum extending over 300 nmhas been obtained, which has beendemonstrated, in collaborative experi-ments at MIT, to replace conventionalsolid state laser technology for invivo Optical Coherence Tomography.

M. W. McCall

Sculptured Thin Films are formed byvacuum deposition of vaporisedmaterial onto a substrate that movesin a periodic fashion during growth.For a rotating substrate a chiralmorphology results in which thematerial forms into helicoidal columns(Fig. 1). Chiral sculptured thin filmshave some promise for various sensingand filtering operations, as theirproperties are selective to circularlypolarised light. Our recent researchhas shown how chiral mirrors can beused to design a circularly polarisedresonator Ð see Figure 2.

M. J. Damzen

We are developing a range of laserand nonlinear optical technology,including novel high power solid-state laser devices for applicationsranging from industrial processing tomedicine, laser displays and remotesensing. Novel diode side-pumpedsolid-state designs operate at highoutput power levels (to 100 W andbeyond) with ultrahigh conversionefficiencies (60%-70%), producingworld-record power levels at somelaser transitions. By incorporatingthese sources with nonlinear frequencyconversion we are developing newcompact efficient sources at highaverage power (multi-watt) in the red,green, blue and UV spectral regionsfor biomedical and laser displayapplications. One of the key problemsto scaling the power of solid-statelasers are strong heating effects in the

Photonics

Optical Fibre Laser Technology

Nonlinear Optics and LaserTechnology

Sculptured Thin Films

Figure 1. Scanning electron micrographof a chiral sculptured thin film (courtesyof Pennsylvania State University).

http://www.imperial.ac.uk/research/phot

Figure 2. (Upper) Open cavity handedresonator formed using a pair of chiralmirrors. (Lower) Spacerless handedresonator.

23

laser amplifier leading to thermally-induced lensing and stress-inducedbirefringence that degrade beam qualityand reduce stability and efficiency ofthe laser. We have pioneered a rangeof nonlinear techniques to providelasers that self-organise to automati-cally correct these adverse effects,including a new self-adaptive solid-state laser systems that maintain thelaser efficiency and output beamquality, based on a novel dynamicholography process within the laseramplifier itself. Such c.w. diode-pumped solid-state lasers with adaptiveresonators operate at many tens ofwatts with diffraction-limited beamquality. More recently, we are devel-oping adaptive interferometers for arange of real-world applicationsincluding remote ultrasound detectionfor non-destructive testing, medicalbiomechanical health and free-spaceoptical communications and remotesensing. A programme to characterisenew nonlinear optical media comple-ments the work on nonlinear optics.As well as including the conventionalbulk nonlinear crystal media such asKTP and periodically poled KTP, wehave developed investigation andapplication of photorefractive mediathat have strong nonlinear effectseven at low light levels < 1 mW. Forfuture nonlinear materials in infor-mation processing and sensors, weare also initiating a new nanotech-nology programme to study nonlinearoptical properties of biological micro-

tubules (and carbon nanotubes).

C. Paterson, G. T. Kennedy, J. Massa,C. Walker

For ground-based astronomy, adaptiveoptics provides a remarkably effectivesolution to problems due to aberra-tions arising from atmospheric turbu-lence and associated random changingrefractive index fluctuations. Theprinciple is to measure the aberrationson light from a known object (such asa guide star) using a wavefront sensorand then to correct for them in real-time using for example a dynamicdeformable mirror. We are applyingthe same principles to a range ofbiomedical and industrial applicationsand are particularly interested inimaging the human eye, in whichaberrations may arise from a number

of sources including static aberrationsin the cornea and lens and dynamictear-film fluctuations. Imaging theretina is important medically sincethe blood vessels in front of the retinagive a unique unobscured view of acomplete section of the cardiovascularsystem - offering enormous potentialfor disease diagnosis and monitoring.Usually individual photoreceptors aretoo small to be imaged but they maybe observed if the pupil is dilated andthe aberrations of the eye are corrected.We are working with ophthalmologiststo apply adaptive optics to imagingof neonatal retinas for the detectionof retinal disease and for studyingthe process of visual development.

We are also applying adaptive optics tocorrect for strong atmospheric turbu-lence, with potential for imaging,remote sensing and communication.This work includes atmosphericmodelling and characterisation appliedto beam propagation and to multi-conjugate adaptive optics - a techniqueusing multiple correction mirrors toincrease the field of view of imagingsystems. As the atmospheric turbu-lence effects increase (e.g. over longoptical propagation distances),scintillation and phase dislocations oroptical vortices also appear, whichpresent enormous challenges toadaptive compensation and for whichwe are developing new wavefrontsensing and correction techniques.We have also started a programmein which we are fabricating our ownadaptive optics components - includingdeformable mirrors, wavefront sensorsand control, specifically to addressthese promising applications.

P. T�r�k

We are researching various meansto achieve much improved opticalstorage capacity, including superresolution techniques by means oftransfer function equalisation, super-resolving filters and multilevel coding,aiming to exploit the maximum infor-mation content by unit area that ispossible to store on an optical disk.

High Resolution Imaging of theHuman Retina using Adaptive Optics

Figure 3: Self-adaptive diode-pumped Nd:YVO4 laser is created by formation of aholographic grating within laser amplifier. The grating encodes and corrects for severeintracavity distortion to maintain high spatial quality output beam.

Figure 4: Confocal scanning ophthal-moscope retinal image

Electromagnetic Focusing andImaging and Applications to Optical

Data Storage, Microscopy andSculptured Thin Films

Accordingly we have developed acomplete set of analytical/numericalmodelling tools Ð which may also beapplied to optical imaging systems.Interaction of light with either thesurface of a CD/DVD or any othercomplex specimen is considered viarigorous electromagnetic solvers.We have developed high angle FiniteDifference Time Domain (FDTD) andVolume Integral solvers. As a resultof our research it is possible tooptimise model performance. Ourtechnique, which is able for the firsttime to combine analytical andnumerical techniques is, to ourknowledge, the most accurate wayof modelling optical microscopes,optical data storage devices andother optical systems for metrology.

To maximise our numerical capabil-ities we have built a computer clusterpossessing 36 nodes, each with 2.4GHz CPU and in total 36 GB memory.This has been used to model howlight is scattered by a surface elementof the next generation of DVD disks(shown in Fig. 5) illuminated by asemiconductor laser (on the left) andthe intensity of light scattered by theindividual data pit (on the right). Ourmodel can provide the distribution ofthe electric field or intensity at thedetector, the detector signal andjitter information, etc.

Our research also includes thedevelopment of methods that arecapable of producing an arbitrarypolarisation structure in the vicinityof focus of high numerical aperturelenses. We take a combination of

vectorial Gauss-Laguerre andGauss-Hermite beams as orthogonalbasis functions and we use them toexpand a Ôwish functionÕ describingthe polarisation structure in question.This research has great use inoptical data storage, ellipsometry andpolarised light optical microscopy.

P. M. W. French, I. Munro, M. Neil,F. Reavell

We continue to apply ultrafast andtunable laser technology, includingcompact diode-pumped all-solid-stateand fibre laser sources, to novelimaging applications with a strongemphasis on multi-parameterfluorescence imaging for clinicaldiagnosis, molecular biology and drugdiscovery. Our main programmesare high speed 3-D coherence gatedimaging and fluorescence life-timeimaging (FLIM). The 3D imagingprogramme builds on our inventionand development of low coherencephotorefractive holography for highspeed depth resolved imaging,including through scattering media,with an inherent rejection of d.c.(diffuse light) background. The useof photorefractive GaAs/AlGaAsMQW devices, in partnership withDavid Nolte at Purdue University,has realized wide-field depthresolved imaging at ~ 500 frames/second. Other techniques for wide-field optical sectioning include lowcoherence interferometric imaging withdirect CCD detection and structuredillumination. Our FLIM programme

has focused on high-speed wide-field image acquisition, offering sub-10 ps temporal discrimination forwide-field functional imaging ofchemical and biological samples,contrasting different chemical speciesand different fluorophore environments.We combined FLIM with multi-spectralimaging and optical sectioning torealize 5D fluorescence imaging andhave adapted FLIM to polarizationanisotropy to image rotationaldiffusion dynamics. Recently wehave demonstrated real-time (15frames/s) FLIM applied to endoscopesand multi-well plate reader systems.

We have also established a confocalscanning/multiphoton microscope,broadly tunable ultrafast laser/OPAtechnology and a multi-beam, multi-photon microscope that provideswidefield optically sectioned imagesat video rate, which has beencombined with hyperspectral andpolarisation resolved imaging aswell as FLIM. In collaborations withcolleagues in the Bioengineering,Biology, Chemistry Departments andthe Faculty of Medicine, we areapplying our unique instrumentationto molecular biology (applying FLIMto genetically expressed probessuch as EGFP, to report both thelocalization and local environment oftarget proteins), to medical applica-tions (using FLIM to provide intrinsicautofluorescence contrast in unstainedtissue samples, with potentialdiagnostic applications) and to drugdiscovery (using multi-parameterfluorescence imaging to developlabel-free assays).

24

Figure 5: Light scattered by a DVD track

Functional imaging for biology andmedicine

Figure 6: Intrinsic FLIM contrast ofunstained (rat) tissue.

25

Head of Group:Professor K. Krushelnick

The Plasma Physics Group conductsresearch on both astrophysical andlaboratory plasmas and is the largestuniversity based plasma physicsgroup in the UK. We are involved infusion energy research and do bothexperimental and theoretical work onmagnetically confined fusion plasmas(in collaboration with UKAEA Culham)and on inertial confinement fusionusing the MAGPIE z-pinch facility inBlackett Laboratory and the highpower laser facilities at the RutherfordAppleton Laboratory.

S. Cowley, G. Turri, N. Joiner, D. Applegate, M. Coppins, A. Meakins,F. Lott, J. Paley, O. Keating,J. Martin

MAST, the MegaAmpere SphericalTokamak, is an experiment operatedat the Culham Laboratory inOxfordshire. This acronym under-lines two main features of this device:the plasma current achieved isgreater than 1 MA and the design isnon-conventional, i.e., the aspectratio is small such that the major andminor radii are comparable in size.

Our Group is studying the studyingmagnetic reconnection in the centralcore of these plasmas both theoreti-cally and experimentally. Of particular

interest is the MHD ÒsnakeÓ instability(because of soft x-ray (SXR) tracesobtained from the diagnostic system,see Fig. 1) which is due to recon-nection of magnetic field lines in thecore plasma.

Plasma instabilities on the scale ofthe ion and electron gyro-radius(micro-instabilities) are also studiedusing gyro-kinetic simulations.Simulations are performed using acode that utilises magnetic fluxfollowing geometry because themost computationally efficientsimulation domains are thin tubes(flux-tubes) which follow the magneticfield lines (see Fig. 2). Micro-instabilities are thought to be thesource of fine scale plasma turbulence.

A. R. Bell

The theory of cosmic ray (CR)acceleration to energies of 1015 eVby diffusive shock acceleration insupernova remnants (SNR) is wellestablished. As a SNR shock expandsinto the interstellar medium, CR areconfined in the shock environment byscattering off magnetic field fluctua-tions receiving a succession of kicksas they are repeatedly overtaken bythe shock.

However, the standard theory cannotaccount for CR energies beyond1015 eV because the CR gyroradiusin a typical interstellar magnetic fieldexceeds the radius of the supernova

remnant. We have shown that thelarge CR flux dominates thedispersion relation and produces anew kind of strongly driven modewhich rapidly becomes non-linearand generates magnetohydrody-namic turbulence.

The turbulence stretches the magneticfield lines, thereby increasing themagnitude of the magnetic field,decreasing the CR gyroradius, andmaking CR acceleration to higherenergies possible (see Fig. 3).

S.V. Lebedev, J. P. Chittenden, S. N. Bland, S. C. Bott, D. J. Ampleford,C. A. Jennings, J. Rapley, M. Sherlock,M. G. Haines

The intense bursts of soft X-raygenerated by fast plasma implosionsare used for Inertial ConfinementFusion research. The physics ofimploding plasmas formed fromcylindrical arrays of fine metallic wiresare studied on the 1.5 MA MAGPIEpulsed power facility. One of thecritical parameters controlling theimplosion dynamics is the rate withwhich the plasma is formed from theablating wires. We have found that

Plasma Physics

Magnetic Confinement fusion experiments and theory

Cosmic ray acceleration andmagnetic field generation

http://www.imperial.ac.uk/research/plasma

Figure 1: Typical SXR data obtainedwhen snake instability develops

Magnetic Confinement fusion experiments and theory

Figure 2: Gyrokinetic simulation of MAST

Figure 3: Magnetic field line before andafter stretching by cosmic rays.

Wire array Z-pinch implosions

Figure 4: Rapid increase of ablationrate for the gaps below ÒcriticalÓ

26

the ablation rate strongly depends onthe magnitude of the magnetic fieldpushing the plasma towards the arrayaxis. The observed dependence of theablation velocity on the inter-wireseparation (Fig. 4) may explain theexistence of the optimum wirenumber maximizing the radiation power.

We use 3D resistive magneto-hydro-dynamics simulations to investigatefactors limiting X-ray power productionin imploding wire arrays. Figure 5shows the broken plasma structureoriginating from sixteen aluminiumwires in a MAGPIE wire array,imploding under the jxB force andconverging on axis. The peak X-raypower is found to be limited by acombination of 3D asymmetry, selftrapping of the radiation flux and areduction in the current delivered toimploded pinch caused by thetrailing mass. Simulations ofdifferent wire array configurationsreveal the mechanisms by which theX-ray power can be increased.

R. J. Kingham, A. R. Bell, M. G. Haines

The physics of the interaction ofnanosecond laser pulses with plasmais relevant to inertial confinementfusion (ICF) plus other applicationssuch as X-ray lasers. At theseintensities (1013 Ð1016 W/cm2) strongnon-equilibrium effects are prevalentand a kinetic (rather than hydrody-namic) description of the interactionis required.

We are investigating the underlyingtransport and magnetic-field gener-

ation phenomena in this regime oflaser-plasma interaction using aFokker-Planck simulation code calledIMPACT.

In particular, we are looking at howelectron transport and magnetic fieldgeneration change under these 'non-local' conditions. As well as being offundamental interest, this situation isrelevant to indirect drive ICF.

Here the conditions in the (ionized)gas-fill and near the walls of hohlraums(i.e., gold, black body X-ray cavities)are far from 'local'. How non-localeffects influence the evolution of thissystem is still an open question.Previously it was known that (without amagnetic-field) thermal transport isnot adequately described by theconventional `Braginskii' theorywhen the mean-free-path becomeslarge: the heat flow cannot simplybe related to the instantaneous,local temperature gradient andplasma conditions. We have shownthat non-local effects are importantto magnetic field generation.

A. R. Bell, A. P. L. Robinson,R. J. Kingham

Irradiation of solid targets by highintensity, sub-picosecond laser pulsesefficiently produces electrons, ionsand photons with MeV energies.We are investigating the underlyinglaser-solid interaction processesusing a Fokker-Planck simulation codecalled KALOS. The absorption oflaser light at the target surface directlygenerates energetic electrons whichstream into the target. To maintaincharge balance, the current ofenergetic electrons must be balancedby an opposite 'return current' ofthermal electrons.

When the beam of energetic electronsreaches the rear surface of the targetthe electrons emerge into the vacuumsetting up an electric field whichreflects most of them back into thetarget and at the same time drawsenergetic ions out into the vacuum.We have reached a point at which

electron beam propagation throughthe solid is reasonably well under-stood, and we are investigating thecomplicated structures in particledensity, ionisation state and electricfield occurring at the rear surface ofthe target which cannot be adequatelymodelled with any other codes.

Z. Najmudin, K. Krushelnick, A. E. Dangor, M. Tatarakis, B. Walton,S. P. D. Mangles, M. S. Wei, E. L. Clark, A. Gopal, C. D. Murphy,A. G. R. Thomas.

The large electric fields at the focusof high power laser systems canaccelerate particles to high energyin extremely short distances. Inrecent experiments, we have usedseveral laser systems to investigatelaser acceleration mechanisms.

The Petawatt laser at RAL can befocused to intensities approaching1021 Wcm-2 with an associatedelectric field of almost 1013 Vm-1.By focusing into a plasma, the trans-verse motion of electrons in thelaser field can be randomised into alongitudinal motion. This allows theelectrons to travel with the laserpulse, experiencing further acceler-ation. In our experiments, we haverecorded electrons accelerated bythis mechanism with energies up to350 MeV Ð the highest recordedfrom such an interaction.

The Astra laser system is a muchmore compact laser system,providing up to 0.5 J laser pulsesbut now in t Å 40 fs laser pulses.These ultrashort pulses are moreefficient at generating plasmawakefields which also have extremelylarge longitudinal electric fields, and

Laser produced plasmas as acompact particle accelerator

Transport and B-field generation innanosecond laser-plasma interactions

Figure 5: Density surfaces from a 3Dsimulation of a 16 wire aluminium wireimplosion.

Laser-solid interaction at ultra-highintensity

Figure 6: Simulation of PetaWatt laserinteraction showing the importance ofpropagation instabilities

can accelerate electrons to high energy.Indeed, the breaking of these wavescan themselves provide the electronsto be accelerated. We have foundthat close to threshold for thisÒwavebreakingÓ process, only a smallbunch of electrons is accelerated.This results in very short durationbunches with greatly reduced energyspread which is important for thedevelopment of future electronaccelerator technology.

A. Ciardi, J. P. Chittenden, K. Krushelnick, A. E. Dangor, F. N. Beg

An x-pinch consists of two or morethin metallic wires crossed in theshape of an ÒXÓ. By applying alarge fast rising current through thewires, several rapid bursts (< 1 ns)of soft x-rays are produced frommicron sized hot-spots, where plasmadensities in excess of 1022 cm-3 andtemperatures of ~ 1 keV are achieved.The complex physical evolution of anx-pinch is studied in detail using ourthree-dimensional resistive magneto-hydrodynamic code (GORGON). X-ray emission is preceded by theformation of jet-like structures and aminiature z-pinch plasma column(Fig. 7). A combination of radiativecollapse and axial flow drive theinitial radial implosion of the z-pinchuntil the onset of MHD instabilitiesfurther compresses regions of theplasma producing the x-ray bursts.

Measurements of the optical and x-ray emission from a small 40 kA, 30 ns(10-90%) rise time X-pinch plasmadischarge have also been made.Initial experiments to demonstratethe use of this X-pinch for applica-tions in x-ray radiography have beenperformed (see Fig. 8).

K. Krushelnick, A. E. Dangor, F. N. Beg, M. S. Wei, A. Gopal, M. Tatarakis

One of the important characteristics oflaser plasma interactions at high inten-sities is the efficient conversion of laserenergy into relativistic electronsleading to the generation of significantreturn currents in the plasma.Experiments were performed usingusing the VULCAN laser system atRAL in which ultra-high intensity laserpulses (I > 5 x 1019 Wcm-2) were usedto irradiate thin wire targets. It wasobserved that such interactionsgenerate a large number of relativisticelectrons which escape the target andinduce multi-Mega Ampere returncurrents within the wire. MHD instabil-ities can subsequently be observed inthe pinching plasma along with fieldemission of electrons from nearbyobjects.

We have also made measurements ofultra-high magnetic fields producedduring these interactions. We haveshown that polarisation measurementsof high-order VUV laser harmonicsgenerated during the interaction (up tothe 25th order) suggest the existenceof magnetic field strengths of 0.7GGauss in the overdense plasma.This technique may be useful for

laboratory studies of exotic highlymagnetised astrophysical objects suchas neutron stars.

M. Coppins, M. Bacharis, J. Martin, D. Selemir

Dusty plasmas are plasmas containingsmall solid particles. Within the lastdecade it has been realised thatsuch plasmas support many uniquephenomena, such as dust crystal-lization. However, the very basicphysical processes in such systemsare not very well understoodtheoretically. This motivates ourprogramme of theoretical andcomputational studies in three mainareas: dust grain charging, dust infusion plasmas, and ÔÔmistyÕÕ plasmas.

Misty plasmas are plasmascontaining small liquid droplets. Thecharging processes are the same asfor solid particles, but now surfacetension plays a significant role.Using the well known Rayleighlimiting charge we find that aplasma-immersed liquid droplet willonly survive if its radius exceeds acritical value given by acrit = e0fd / 4g,where fd is the potential of the dropletand g is the surface tension.

27

Dusty Plasmas

X-pinch Simulations and Experiments

Ultra-high intensity laser interactionswith solid density plasmas

Figure 7: Surfaces of constant densityfrom 3D simulation of a molybdenum x-pinch.

Figure 8: X-ray image of house flytaken with Òtable-topÓ x-pinch.

Figure 9: High order laser harmonicsranging from 7th to 25th order (right toleft). By comparing the top set (s-polarised) to the bottom set (p-polarised) the magnetic field in theplasma can be determined.

28

Head of Group:Professor J. P. Marangos

The research mission of the QOLSgroup is to carry out basic scienceusing lasers and to investigate, utiliseand control photonic and materialstates and processes down to thequantum level. We include a QuantumOptics Theory team that is carryingout ground breaking research inquantum information science. Alsowithin QOLS advanced computationaltechniques are being applied toresearch in quantum information,laser dynamics and non-linear opticsand ultra-short laser pulses. There is abroad portfolio of experimental workwithin the group focusing on; iontrapping, atoms confined within clustersand within nanostructures, atomicand molecular coherence in non-linear optical processes and coldmatter (i.e. cold atoms, BEC's andcold molecules).

P. L. Knight FRS, M. B. Plenio, V. Vedral, A. Beige, V. Kendon, T. Rudolph, S. Scheel.

We have continued our work on allaspects of quantum entanglement.

Quantum optical realisations forentanglement generation and manipu-lation that we have studied includeBose condensates undergoing Motttransitions while confined on an atomchip, atoms or ions trapped withinhigh quality optical cavities and lineartraps. Especially we have been inter-ested in to what extent dissipation canbe used to improve the fidelity ofcertain quantum computing schemes.

We have achieved a full characteri-sation of entanglement transformationsbetween pure states in the practicallyimportant setting of linear opticaldevices. We have proposed a novelprotocol for the creation of long rangeentanglement in this setting. We havefurthermore proposed protocols forthe generation of entanglementbetween distant atoms or ions trapped

inside optical resonators. We havealso studied the use of single photonsources in quantum communicationand linear optical quantum computing.

In the abstract theory of entanglementwe have achieved some excitingresults that suggest that entanglementmanipulation can be reversible whichwould, if proven in general, imply aformal equivalence between such atheory of entanglement and anaxiomatic foundation of thermody-namics. This work has also providedoperational interpretations of hithertoentirely abstract but easily computablemeasures of entanglement.

Our recent work has established thatquantisation of the random walk, knownas the quantum walk, leads to aquadratic enhancement of spreading.We have been investigating realisa-tions of quantum walks within quantumoptics, and analysing them as anexample of quantum algorithmsdemonstrating quadratic speed-upallowed by quantum mechanics.

We have investigated the effect ofthe field quantisation on the value ofthe Berry phase. We have found thatthere is an extra factor of one halfgained by the phase even when thefield is in the vacuum state (whichhas no classical counterpart). Wesuggested a feasible experiment toobserve this phase in cavity-QED. Wehave investigated the opposite limitof the geometric phase, where thereis a continuum of modes interactingwith the two-level system acquiringthe phase. This leads to a decoheringevolution of the system and we wereable to show that the phase isresistant to some errors. Our methodalso presents another way of definingthe mixed state geometric phasethat is very operational.

We showed that the amount of infor-mation in a measurement involvinga quantum apparatus is proportionalto the amount of classical correla-tions between the system and theapparatus (rather than the amount ofentanglement as previously thought).

The novel feature of our treatmenthas been the fact that the initial stateof the apparatus has been assumedto be mixed rather than pure (as invon NeumannÕs and EverettÕs). Wehave also been able to derive aninequality bounding the amount ofinformation gain by the mixednessof the initial state of the apparatus.

G. H. C. New, P. Kinsler, M. Yates,C. Tsangaris, J. Tyrrell

Numerous theoretical projects in laserphysics and nonlinear optics wereundertaken. We completed an in-depth study of the Virtual Sourcemethod for generating one-dimen-sional modes and the power methodwith shift that enables the Fox-Limethod to be extended to the two-dimensional case. We made signif-icant progress in the modelling oftransverse effects in nonlinear opticalinteractions. We showed that atechnique based on a spatial frequencydecomposition used by other authorswas both cumbersome and restricted,in that it could no readily accom-modate diffraction and birefringence.We developed a straightforwardsplit-step method that was faster,and took all the main physicalphenomena into account.

In work on few-cycle optical pulses, wepredicted the existence of a bandwidth-dependent velocity shift both for c(3)

(Kerr) solitons and for pairs of co-

Quantum Optics and Laser Science

Quantum Optics and QuantumInformation

Novel Laser Phenomena andNonlinear Atom and Photon Optics

http://www.imperial.ac.uk/research/qols

Figure 1: Atoms trapped in a standinglight wave can be manipulated by currentsprovided by a chip substrate; an appliedlaser field from the side can modify thetrapping potentials and allow tunnellingbetween wells to realize a quantum logicgate.

29

propagating c(2) solitons. Progresswas also made on the handlingoverlapping frequency bands inwideband nonlinear optical interactions.

We started to build Finite-DifferenceTime-Domain (FDTD) codes fortreating the nonlinear interaction offew-cycle pulses. In studying self-phase modulation, we rediscoveredthe problem of carrier wave shocks,and began a detailed exploration ofthe parameter regime in which theseoccurred. We initiated work onpseudo-spectral approaches to FDTDanalysis which, if successful, willmake the incorporation of dispersionmuch more straightforward.

We continued work on opticalparametric chirped-pulse amplification(OPCPA) and synchronously-pumpedoptical parametric oscillators (OPOs).We discovered a novel short-cavityoperating regime in synchronously-pumped OPOs, and are currentlycollaborating with colleagues at StAndrews to see if the results can bereproduced experimentally.

E. Hinds, B. Sauer, A. Curtis, S. Eriksson, B. Hall, J. Hudson, J. Rogel-Salazar, M. Tarbutt

The cold matter team moved fromSussex at the beginning of 2003.Setting up the experiments in thenewly renovated space in Blackettprovided us the opportunity to makesome significant upgrades to ourapparatus. We run two experimentsdedicated to studying atom optics andBose-Einstein condensates (BEC) inminiature magnetic traps - one whichrelies on magnetised videotape toprovide the primary trapping potentialand one which uses current carryingwires. We have used the wire trap tostudy thermally induced spin flips in atrapped BEC. This same system wasused to study the inhomogeneousmagnetic field produced by the currentcarrying wires. The variations in themagnetic field cause the trapped BECto fragment, an effect which needs tobe understood if atom chips are to beuseful for more complicated devices.Traps produced from permanentmagnetic materials, like our videotape

trap, do not suffer from the sameinhomogeneities. We have added atapered amplifier laser system to ourvideotape trap apparatus. This allowsus to trap an order of magnitudemore atoms and should thereforeallow us to study BEC in a permanentmagnet trap. We have also developedthe technology to write magneticpatterns on Pt-Co multilayer films.This technique reduces the trap sizeby an order of magnitude comparedwith videotape, with a correspondingincrease in trap frequency. Thenanoscale traps we will be able toproduce will form the cornerstone ofour new programme to study BEC inlow dimensions.

As part of our plans to slow and trapcold molecules, we have recentlysucceeded in slowing a beam of YbFmolecules in a alternating gradientdecelerator. This work used a shortelectrode structure as a proof ofprinciple. We are currently constructinga much larger decelerator which willslow YbF from 280 m/s to 80m/s,removing 90% of their kinetic energy.As part of the decelerator work wedeveloped a pulsed supersonic sourceof YbF molecules. The moleculesfrom this source form an intense,rotationally cold beam which is idealfor our experiment to measure thepermanent electric dipole moment(EDM) of the electron. We haveincorporated such a source into ourEDM apparatus and preliminary

measurements show that it shouldgive us at least a factor of threeincrease in sensitivity. This wouldmake our electron EDM experimentthe most sensitive in the world.

S. Gundry, M. P. Anscombe, A. M. Abdulla, S. D. Hogan, E. Sali,J. W. G. Tisch, J. P. Marangos

It is well known that a gas can actas an efficient modulator for laserradiation if coherent molecular vibra-tions are excited within it. Sokolovet al showed in 2000 that two laserfields applied near to Raman resonancein a sample can efficiently preparesuch a molecular modulator if theevolution of the system is adiabatic,thus necessitating the use of few-nanosecond laser pulses. Thesepulses were shown to be modulatedwith high efficiency in the medium toform a Òfrequency combÓ of highintensity Raman sidebands coveringa remarkably broad frequency range.Due to the discrete nature of thespectrum generated by the modulator,a pulse train, rather than isolatedpulses, is produced. In the case ofthe nanosecond fields needed toadiabatically prepare the modulator,the train of pulses produced containsabout 106 members at necessarilyvery low energy. We have demon-strated the additional modulation ofboth 3 ns and 100 fs pulses in amedium in which a molecularmodulator has been pre-prepared asdescribed above. The latter caseoffers the possibility of the generationof a short train of about 10 highenergy subfemtosecond pulses. The laser fields used to prepare themolecular modulator were at wave-lengths of 807 nm and 1064 nm,coupling the fundamental vibrationaltransition in D2 (2993.6 cm-1). Thepulse durations of these fields were3.5 ns and 8 ns respectively, producingintensities in the range 0.4-0.8 GWcm-2.These fields were themselvesmodulated to produce a chain oftypically 8 sidebands (see Fig. 4).This indicated that a strong molecularmodulator, or coherence, had beengenerated in the sample. Themodulation of a field at 400nm with

Cold Condensed Matter

Figure 2: 2 mm magnetic lines drawn ona Co-Pt film.

Figure 3: The prototype YbF decelerator.

Non-linear optics in a coherentlyprepared molecular medium

30

a pulse duration of 3 ns was theninvestigated. Five sidebands wereobserved covering the wavelengthrange 294-525 nm. These sidebandswere not observed if a molecularmodulator was not prepared in thesample. The modulation of a secondfield at 400 nm, but a pulse duration of100 fs was then investigated. Weobserved three Raman sidebands ofthe 400 nm field only when themodulator was prepared.

R. C. Thompson, D. M. Segal

The experimental work of the IonTrap group is concerned with usinglaser-cooled trapped ions as a toolto perform experiments in quantumoptics and fundamental physics. Anion trap is an electrode structurewhich holds ions at a well-definedposition under ultra-high vacuumconditions for extended periods.There are two classes of trap:radiofrequency (rf) traps and Penningtraps. The former employ high voltagerf potentials applied to the electrodestructure to generate a three-dimen-sional pseudopotential well in whichthe ions are trapped. On the otherhand Penning traps use only a staticelectric field and a static magneticfield to achieve trapping. We workwith both types of trap but concen-trate particularly on the Penning trap.We are able to load and detect asingle atomic ion in our trap. Thestarting point for all of our experimentsis to apply laser cooling to reducethe temperature of the ion or ions towithin one degree of absolute zero.

Ions held in a Penning trap are notas well localised as they are in an rftrap and this has, in the past, beenseen as a limitation of this approach.Recently we have been investigatinga technique for increasing the effec-tiveness of laser cooling in thePenning trap, thus improving the

localisation of the ion. We also havean interest in the sympathetic coolingof molecular ions, in which suchions are cooled through long-rangeCoulomb collisions with laser-cooledatomic ions held in the same trap.

One of the areas of strong currentinterest in the ion trapping communityis quantum information processing(QIP). One of the greatest practicaldifficulties in this field is in controllingthe decoherence of the delicatequantum superposition states needed.Our aim is to study decoherenceprocesses in a Penning ion trap anddevelop a novel segmented miniaturePenning trap for use in QIP. As partof this work we have recently achievedlaser cooling of calcium ions in aPenning trap for the first time.We are also participating in new

European Network concerned withthe study of highly-charged ions intraps. Our part in this is to developtechniques for performing laserspectroscopy on such ions, whichcan yield important informationconcerning their nuclear and atomic

properties.

J. P. Connerade, C. Garcia-Segundo,A. J. Smith, S. D. Hogan

Experiments on Rydberg atoms incrossed electric and magnetic fieldshave been extended into a rangewhere manifestations of 'quantumchaos' are expected, and wheretheoretical predictions based onquantum mechanics presently exceedthe computational capabilities ofworld-leading theoretical groups.Interesting regularities have beenobserved which extend the currentstate of knowledge, and the implicationsof our results are being assessed. Ourexperiment is currently the only onecapable of yielding such informationon systems with classically chaoticdynamics in three-dimensions.

The theoretical study of confinedatoms has been advanced throughthe investigation of non-sphericalsystems with spheroidal deforma-tions, based on similar models formetallic clusters, and through theinvestigation of different types ofconfining shell.

Our work on the development ofnew detectors has progressed withthe support of Shimadzu ResearchLaboratories (Europe) Ltd, leadingto a joint patent application filed onbehalf of SRL and Imperial College.

Figure 4: High order Raman sidebandsof the fields preparing the molecularmodulator.

Ion Traps and Laser Cooling

Confined atoms and atoms inexternal fields

Figure 5: A CCD image of a singleaxialised Mg+ ion in a Penning trap.

Figure 6: An ion trap which may beoperated as a Penning trap or as aradiofrequency trap.

Figure 7: High-lying s- Rydberg states ofbarium in crossed electric and magneticfields.

31

Space and Atmospheric PhysicsHead of Group: Professor J. E. Harries

The Group continues its research inthree closely related areas: the physicsof the Solar interior and the ionisedand magnetised outer atmosphereof the Sun; the extension of the solaratmosphere into interplanetary spaceas the solar wind; and the physics ofthe EarthÕs neutral atmosphere andthe role it plays in the climate system.

The space programme continues tobe lively and active (Fig. 1). The firstof the two Double Star spacecraftwas launched in late 2003 and theRosetta spacecraft, carrying anImperial College data processingsystem, was launched in March2004. Another major mission for usis Cassini as preparations continuefor the insertion of the spacecraftinto Saturn orbit on 1st July 2004.We are the Principal Investigatorinstitute for the magnetometer, andcollaborators of the Ion NeutralMass spectrometer team.

The first Geostationary Earth RadiationBudget (GERB-1) experiment, for whichwe have the Principal Investigator role,has been in operation for over a yearon the European MSG-1 satellite.New, high time resolution and high

accuracy measurements have beenmade of the radiative energy balanceof the Earth, allowing novel studiesto be made of key processes withinthe climate system that affect theevolution of climate.

P. Cargill, M. J. Thompson

Our programme in solar physics aimsat understanding the physics of theSunÕs interior and atmosphere,especially those dynamical processesthat play a key role in the SunÕs 11-year magnetic cycle and activity.

We study the solar interior seismically,using observations of predominantlyacoustic waves that propagate throughthe Sun. Our recent research hasused local helioseismology to studystructures and flows under sunspotsand in the upper part of the SunÕsconvection zone, using data from theGlobal Oscillation Network Group andfrom the MDI instrument on board theSOHO satellite. We have conductednumerical simulations to elucidatethe sensitivity of tomographic datafrom the Sun to different aspects ofthe sub-photospheric structure. This

is part of a project, with the Departmentof Earth Sciences, to adapt geoseismicanalysis techniques to studying theSun (Fig 2). We have also continuedour study of the tachocline shearregion where the large-scale magneticdynamo is widely believed to reside.

Our studies of the fine structure ofthe solar corona have focused onthe generation of synthetic emissionmeasures differential in temperatureand density, and filling factors. Thispermits an understanding of how themultiple temperatures and densitiesof the coronal plasma combine toproduce the observed emission.Interpretation of coronal fine structureis a very sensitive function of thetemperature used to make theobservations.

A. Balogh, P. J. Cargill, R. J. Forsyth,T. S. Horbury

The Ulysses mission continues toprovide unique observations of theheliosphere from its orbit around thepoles of the Sun. After 14 successfulyears, the mission has been extendeduntil March 2008. The study ofCoronal Mass Ejections (CMEs)remains our main topic of interest,particularly their 3D magnetic structureas they propagate away from the Sunat all solar latitudes. Major solaroutbursts unexpectedly disturbedthe heliosphere in late 2003, andobservations showed large CMEsdominating the heliospheric structureand dynamics.

Our theoretical work has investigatedthe possibility of predicting thearrival time of CMEs at the Earth,and their interaction in the solar wind.We have shown that typical errors inpredicting the arrival time were under20%, despite the use of a wide rangeof empirical models. We have alsoshown that interacting CMEs undergoa form of cannibalism, with onedevouring the other and are likely tobe sites of enhanced production ofhigh-energy solar cosmic rays.

Heliospheric Research

Solar Physics

Figure 1: Launch of the first Double Starspacecraft.

http://www.imperial.ac.uk/research/spat

Figure 2: High-resolution syntheticseismogram of subsurface waves travellingbetween different points on the sun'ssurface. Visible are the arrivals with (a)no intermediate bounces, (b) one bounce,(c) two bounces and (d) an asymptoticarrival.

M. K. Dougherty, A. Balogh, I. Mueller-Wodarg

In preparation for the arrival of theCassini/Huygens spacecraft, we arebuilding an empirical global magnetos-pheric model for Saturn to predict themagnetic field we expect to observe.We have revisited the magnetic fieldobservations from the three previousflybys of Saturn in order to betterunderstand both the planetÕs internalfield and rotation rate.

Analysis of data taken by Cassinifrom the Jupiter fly-by in late 2000has continued. This data, used inconjunction with a magnetohydrody-namic model of the solar wind, hasallowed us to examine the response ofthe Jovian magnetosphere to changesin the external driving conditions. Adetailed study examined themorphology of the bow shock surface,the relationship between shock sizeand solar wind pressure, and wavesin the upstream magnetosheath atJupiter during the flyby.

Titan has a nitrogen-rich atmospherewhich extends considerably into space,compared with the moon's solid bodyradius. Work on a 3-dimensionalglobal circulation model of its upperatmosphere is making predictions

for the observations planned for theHuygens probe and Cassini orbiter(Fig. 3). This model is also beingused in science planning by thevarious instrument teams.

Rosetta, an ESA mission to cometChuryumov-Gerasimenko, carries adata processing system provided bythe group which supports theRosetta Plasma consortium, with theaim of observing the cometÕs devel-opment from the rendezvous point indeep space in 2014 throughmaximum activity at perihelion. Weare also a co-investigator institutefor the magnetometer.

A. Balogh, P. J. Cargill, C. Carr, T. S. Horbury, E. A. Lucek

Analysis of data from the four space-craft of the unique Cluster mission,allows us to probe the interactionsbetween the solar wind and the EarthÕsmagnetic field as well as fundamentalplasma processes such as shocks andreconnection. The magnetosphericcusps, where the solar wind penetratesclose to the Earth, have remained afocus of our analysis. One objectiveis to determine cusp structure anddynamics as a function of solar windconditions and season. We havealso shown that magnetic fieldturbulence in the cusps is strongly

correlated with sheared plasmaflows, suggesting an origin inplasma jets associated with themagnetic reconnection process.We have also used Cluster observa-tions to determine the sizes of struc-tures within the EarthÕs bowshock. Insome cases, shock structures aremuch smaller than expected fromearlier data and theory, probablydue to instabilities caused byenergetic particle gradients andelectron dynamics.

Double Star is a joint project betweenthe Chinese and European spaceagencies, to place two spacecraft,each carrying magnetometerssupplied by the Group in Earthorbits complementary to those of theCluster spacecraft. Analysis hasstarted of measurements from thefirst spacecraft and we await thelaunch of the second spacecraft ofthis exciting mission in July 2004.

J. D. Haigh, R. Toumi, J. E. Harries

Experiments have been carried outwith a simplified global circulationmodel to investigate the climateÕsresponse to solar activity. The resultsshow a weakening and polewardshift of the sub-tropical jet streams(Fig. 5) which is qualitatively verysimilar to signals previously derived

Solar Terrestrial Physics

Modelling of the EarthÕs Atmosphere

Figure 3: The solar heating rates in Titan'sthermosphere (ring-shaped contours)show that solar radiation poleward ofaround 60 deg latitude penetrates fromthe dayside (right) to the nightside (left).This has important implications for theglobal temperatures, winds and neutraland ion composition.

Planetary Plasma Physics

32

Figure 4: Magnetic field and plasma data from the four Cluster spacecraft for a cuspcrossing

33

from observational data. Thisdemonstrates that perturbations tothe heat balance of the lowerstratosphere can produce changesin the mean circulation of the loweratmosphere even without any directforcing to the latter.

Currently most numerical models thatsimulate cumulus and stratocumulusclouds have to use some form oftemporal and/or spatial averaging ofthe small-scale turbulence in orderto make the calculation computa-tionally practicable. In collaborationwith the Department of Aeronautics,we have developed a model thatexploits a kinematic approximationof turbulence allowing us to followindividual cloud droplets. Understandingthis feature is essential in determiningcloudsÕ role in the dynamical-radiationfeedback processes of the EarthÕsclimate.

We have developed a new modelfor storminess and droughts basedon the conservation of angularmomentum in a rotating frame drivenby random fluctuations. This modelpredicts a higher return period ofextreme events than standard statis-tical models and agrees better withobservations over the UK.

J. E. Harries, J. D. Haigh, R.Toumi,V Moore

We have studied the temporalvariability and characteristicfrequencies in the outgoing longwaveradiation (OLR) emitted by the Earth,with a view to understanding the keyprocesses that control the variability

of the EarthÕs emission to space. Acomparison of observations and modelresults for a region of the tropicalPacific associated with El Nino showsthat the model produces more powerin the annual cycle than is observed,while generally reproducing theprincipal signatures (e.g. the El Ninosof 1982/3 and 1999). Such goodsimulation of observation is notrepeated elsewhere around theglobe and studies are continuinginto the causes of this behaviour.

We continue with the calibration,validation, and scientific exploitationof the GERB experiment data. Theclear sky flux can only be measuredin the absence of clouds, reducingthe amount of available observations,but by using higher spatial resolutioninformation from the core sensor onthe MSG-1 spacecraft, SEVIRI, to lookbetween the clouds we can estimatethe clear sky flux at the GERB footprintscale. The difference between theall-sky and clear sky fluxes, is thelong wave cloud forcing (Fig. 6),which provides a quantitative estimateof the reduction in the emission ofradiation to space due the presenceof cloud. This is a key parameter inunderstanding the EarthÕs radiationbalance, and possible changes inthis balance.

Water vapour is the dominant green-house gas and we need to understandits variability and distribution. Wefound a surprising moist pool overthe desert in Asia Minor during thesummer in water vapour observationsmade from space, where one wouldexpect a dry region of descent. Wehave identified a new mechanism thatallows rapid turbulent pumping ofwater vapour into the upper atmos-phere. This moisture becomes trappedin the monsoon wind fields givingrise to the observed moist pool.

We are using spatial statistical analysistechniques and global data to studythe energetic atmospheric response tosolar particle events. Characterisingthe spatial and temporal scales in aglobal analysis will provide more insightinto possible causal mechanisms.

J. E. Harries, R. Toumi, J. Pickering

The Tropospheric Airborne FourierTransform Spectrometer (TAFTS) isa unique instrument, designed tomake measurements of the farinfrared spectrum within the atmos-phere. During flights in late 2002over tropical Australia spectra weremeasured for clear skies and forcirrus cloud. Spectra were takenwithin the cloud where the atmos-phere is opaque to TAFTS and inclear sky regions with broken cirrusabove with higher transmittanceregions of the spectrum show lowerradiance. It is from these ÔwindowsÕthat the data will be used to probethe FIR radiance properties of cirrusice crystals and in turn how cirrusclouds affect theradiative propertiesof the atmosphere.

Work on further GERB instruments,to fly in a continuous operationalseries over the coming decade, hascontinued. GERB-2 and 3 havebeen calibrated using our EarthObservation CharacterisationFacility, and GERB-4 calibration is totake place during the coming year.

Our laboratory spectroscopy activities,in collaboration with Dr A P Thorne(QOLS), use our world-class highresolution visible-VUV FourierTransform Spectrometers. We arestudying atomic and molecular spectraof importance in astrophysical andplanetary atmospheric physics appli-cations, with typical accuracies of 1part in 107 for wavelength and 10% foroscillator strength measurements.Molecular spectroscopy has involvedfurther studies of SO2 at varioustemperatures.

Instrumentation Development

Earth Observation and Data Analysis

Figure 5: Longitudinal average ofwesterly winds as a function of latitudeand height. Black curve: standard atmos-phere; green curve: the result ofimposing heating in the lower stratos-phere (only), simulating the effects ofenhanced solar activity.

Figure 6: Long wave cloud forcing withdata presented as the 28 day mean(17/12/03-13/01/04) at the 1200 UTCtime-step.

34

Theoretical Physics Head of Group:Professor K. Stelle

Our work spans a varied set ofresearch areas with the problems ofgravitation and its interactions withother matter and forces as a centraltheme.

The Theoretical Physics Group hasrecently been enhanced with thearrival of Professors Chris Hull andJerome Gauntlett and Drs Fay Dowkerand Dan Waldram. With eleven currentstaff members, senior researchfellows and long-term senior visitorssuch as Professors Carl Bender andMichael Green, our work is at theforefront of theoretical physicsactivity worldwide.

C. W. Bender, D. C. Brody, T. S. Evans,H. F. Jones, T. W. B. Kibble, R. J. Rivers

Quantum field theory is the mostsuccessful and complete descriptionof processes at small scales or highenergies, be they fundamental particlesor effective modes in laboratorymaterials.

Current uses of field theory in theearly universe and heavy-ion collisionsrequire thermal field theory - adescription of systems at hightemperatures and densities whichmay well be out of equilibrium. Asone important application, duality isbeing used to explain the nature ofconfinement in QCD-like gaugetheories, which mimic the way inwhich the quark-gluon plasma of thehot universe condenses into hadrons.Duality is a powerful concept,whereby a quantum field theorypermits totally different realisationsin terms of constituent fields. We areexploring compactification techniques,whereby the three space dimensionsof the real world can be replaced bya single spatial dimension for thepurposes of isolating the relevanttopological degrees of freedom of a

hot plasma. This same dual approachis enabling us to examine theanalyticity of systems with highchemical potential, with direct impli-cation for lattice calculations, forwhich chemical potentials poseconsiderable computational difficulties.

In fact, one phase of QCD that maybe indirectly observable in neutronstars is the colour conducting/super-fluid phase of large chemical potential.A significant aspect of this is theproduction of vortons, vortex defectswith non-trivial cores. Vorton-likedefects also occur in Bose-EinsteinCondensates, high-Tc supercon-ductors and superfluid 3He. We arestudying such entities in dissipativesystems, to see whether they obeysimple causal scaling laws in theirproduction. Preliminary results saythey do.

The similarities between quantumfields in the early universe andcondensed matter systems go farbeyond vortons. A very fruitfulapproach has been to look for parallelsbetween non-equilibrium condensedmatter systems and fields in the earlyuniverse and to make predictionsthat can be confirmed by experimentin the former, which are impossiblein the latter. To this end, we arecurrently performing experimentswith annular Josephson junctions totest causal scaling bounds on theproduction of domains that mimicthose of quantum field theory. Afterthe success of our first experiment inthis area, we have redesigned it to testthe efficiency of causality with evengreater accuracy. We have also usedthe results of recent experiments onthe spontaneous production ofmagnetic flux in superconducting filmsto develop a better understanding ofthe transitions of gauge theories in theearly universe. In a related context,we have used experimental resultsfor planar liquid crystals to understandthe different efficiencies in producinggross and net topological charge.Returning to gauge theories, wehave used closed time-path methods

to show how the non-gaugeenvironment in the early universe isthe main ingredient in driving theonset of their classical behaviour.

Of great importance in early universecosmology are the details of theinflationary epoch, which is oftendiscussed within the framework ofquantum mechanics, or even inclassical terms. However, a fulltreatment requires quantum fieldtheory. This is a fundamentally non-perturbative problem, for whichcalculation techniques are sparse.To date the only available methodshave been the Hartree-Fock methodand the large-N expansion. In thequantum mechanical context thesemethods have been shown to beinferior to the linear delta expansion.This latter expansion has now beenextended to continuum quantumfield theory, using the closed time-path formalism, up to second order.The results are intermediate betweenthose of the other two methods.With similar aims, lattice linear deltaexpansions have been performed toseventh order.

In a different context, the ideas oftransitions and percolation havehelped us to identify many of thesalient properties of networks, intheir increasing use in providingdescriptions of physical, economicand social systems.

We have explored further the propertiesof systems with non-Hermitian butPT-symmetric Hamiltonians, both inquantum mechanics and in quantumfield theory. In both cases we havebeen able to carry out a perturbativeconstruction of an operator C, whichdefines a Hilbert space with apositive definite metric and so allowsa probabilistic interpretation of thetheory. In the area of quantum fieldtheory we have concentrated ontheories with cubic interactions. Ascalar gj3 field theory is often usedas a pedagogical example of pertur-bative renormalization even thoughthis model is not physically realistic

http://www.imperial.ac.uk/research/theory

Particles, Fields and PhaseTransitions

35

(the energy is not bounded below).However, we have shown that wheng = ie is imaginary, one obtains a fullyacceptable quantum field theory andwe have shown how to constructperturbatively the Hilbert space inwhich cubic scalar field theories in(D+1) -dimensional Minkowskispace-time have positive spectra,are self-adjoint, and exhibit unitarytime evolution. We have alsostudied if2c and ifcy quantum fieldtheories.

H. F. Dowker, J. J. Halliwell, C. J. Isham, I. Raptis, K. Savvidou

An important approach to quantumgravity is the causal set approach,which supposes that spacetime is adiscrete set with a causal order whichcan be thought of as a microscopicnotion of before and after. We haverecently proposed a model formassive particles propagating on abackground causal set. The modelis Lorentz invariant, in contrast to allother models of this type. It predictsthat particles undergo a diffusion inmomentum space and that some ofthem therefore will accelerate tovery high energies over the lifetimeof the universe providing a possiblemechanism for high energy cosmicray production. We have also workedon a model of dynamical collapsefor a field theory on a lattice.

Our group has continued theconstruction of a new approach toquantising systems whose configu-ration space points (or the historytheory analogue) have internalstructure. This is motivated by thedesire to construct genuine quantumtheories of causal sets, or space orspace-time topologies: systems thatcannot be handled using standardquantisation methods that assumethe configuration/history space to bea differentiable manifold.

The central idea in this scheme is toidentify the entities of interest asobjects in a category, whose arrowsthen play a role analogous to that ofmomentum in standard theories.This new scheme reproduces the

standard techniques for manifolds,but includes very many systems thatcannot be handled at all by conven-tional methods.

In view of the grave failure of classicaldifferential geometric methods inattempts to quantise general relativityby retaining a smooth backgroundgeometrical spacetime manifold, ourwork has opted for an alternativecombinatory-algebraic route toquantum gravity. In the past year, wehave continued a major project ofapplying MalliosÕ recently developedCalculus and, in extenso, basemanifold-free, sheaf-theoretic AbstractDifferential Geometry to a finitistic-algebraic scenario for quantumspacetime structure and dynamicsthat was proposed by us in connectionwith SorkinÕs causal set approach toLorentzian quantum gravity.

In another development, we havecontinued a detailed study of theproblem of continuous time in theconsistent histories programme. Inparticular, the main contribution herehas been the development of thetemporal structure of the historiesformalism based on the key obser-vation that ÒtimeÕÕ arises in the theoryin two natural waysÑ-as the label intemporal logic, and as the label indynamics. The most recent result ofthis work came from the study of ahistories version of general relativity,which combines the Lagrangian andHamiltonian formalism. It allows thecoexistence of covariant objects, suchas the Lorentzian four-metric, withcanonical ones, such as the spatialthree-metric, in a way that preservestheir geometric relations. This propertyguarantees the spacetime characterof the canonical variables.

A number of our recent papers haveconcerned the application of thedecoherent histories approach tomodels that do not possess a timecoordinate, such as one encountersin quantum cosmology. We have alsoworked on a very general under-standing of the emergence of classicalphysics from quantum theory, and inparticular, understanding how effectiveevolution equations of hydrodynamicform can arise. We have recently

given a specific demonstration ofthis in the context of oscillator chainmodels. We have also been investi-gating how entanglement is destroyedby a decohering environment insome simple models.

M. Abou-Zeid, A. Fotopoulos, J. P. Gauntlett, M. B. Green, P. Henri-Labord�re, C. M. Hull, J. Kalkkinen, M. Majumdar, D.Martelli,P. Pouliot, J. Sparks, K. S. Stelle, A. A. Tseytlin, D. Waldram

One focus of our work has beenAdS/CFT duality, which relates stringtheories in curved backgrounds togauge theories. Building on oursuccessful semiclassical approachto quantisation of superstrings inAdS5 ´ S5 in the large R-chargesector (small strings with largeangular momentum), we havedeveloped a more general perspectiveon the possible string states thatshould be dual to ÒlongÕÕ gauge-invariant operators with severallarge spins.

One can compare their energy as afunction of the spin to anomalousdimensions of the correspondingoperators. This led to a remarkablenew test of the AdS/CFT duality fornon-supersymmetric states and anew perspective on their classifi-cation. The rotating string solutionsare described by a special integrablesystem - the Neumann model of anoscillator on a sphere. Integrabilityon the string side appears to berelated to integrability of the spinchain model, the Hamiltonian ofwhich represents the (one-loop)anomalous dimension operator ingauge theory.

Supersymmetric backgrounds playcentral roles as M-theory vacua orsolitons and also as the gravity dualsof supersymmetric field theories inthe AdS/CFT correspondence.Without matter these backgroundsare special holonomy manifolds, andrecent work has focussed on ageneralisation to the case with n-form flux. A central idea is the use ofG -structure and intrinsic torsion tocharacterise the geometry. This has

Quantum Gravity and theFoundations of Quantum Mechanics

String Theory and M-Theory

36

led to a complete classification ofthe supersymmetric solutions ofvarious supergravity theories, andthe structure conditions typicallyhave a simple interpretation in termsof generalised calibrations. Thisapproach has led to the explicitconstruction of a number of interestingnew solutions.

A particularly important application isto find new gravity duals to super-symmetric field theories. We havefound the form of the most generalwarped M-theory backgrounds withan AdS3, AdS5 or flat Minkowskifactor, and several new classes ofsolution were found. In certain casesthese are dual to type IIB backgroundsand provide new examples ofSasakiÑEinstein metrics.The dual field theories can alsohave the interesting property of anon-compact R-symmetry. Thisapproach has led to a novel andgeneral construction of SasakiÑEinstein metrics of any dimensionas bundles over K�hlerÑEinsteinspaces. Key to these examples iswhether the n-form fluxes aresuitably quantised. In this contextwe have also given a proof of theFreedÑWitten anomaly shift in theflux quantisation on a D6-brane,relating it to the corresponding shiftin four-form quantisation in M-theory.

We have also followed an alternativeapproach to the study of supersym-metric solutions through generalisedholonomy. This led to interestingdifferences between the classical andquantum theories, giving importantclues to the symmetry structure ofquantum M-theory. We have alsostudied the string-theory correctionsto spaces of special holonomy,particularly the first non-trivialcorrections which are quartic incurvatures. These generate softdeformations of K�hler and G2holonomy manifolds that nonethelesspreserve the corresponding Killingspinor structures. This analysis alsoyields explicit expressions for thecorrections to non-compact Calabi-Yau and G2 manifolds of interest forbraneworld cosmological models.

We have studied strings in curved

gravitational plane-wave backgrounds,with potential applications to cosmo-logical singularity issues. For a largeclass of time-dependent plane-wavebackgrounds, first-quantised stringtheory can be solved exactly in termsof free oscillators and its spectrumcan be studied explicitly. In the caseof singular backgrounds, one is ableto specify certain boundary conditionsunder which string propagation isnot sensitive to the singularity at theorigin. Similar work was done in thecontext of ÒstandardÕÕ cosmologicalbackgrounds, suggesting that stringresolution of singularities happens ina more general context. We havestudied the implications of thesuperalgebra structure of supersym-metric plane wave backgrounds.

We have found an extension of theusual K�hler type of supersymmetricsigma model to complex flatgeometry. We have investigated thegeometry of gauge fields on M-branes, in particular the associatedholonomies and their cohomologicalstructure. We have analysed certainrandom walks (Stochastic LoewnerEvolution) on Riemann surfacesusing conformal field theory. Wehave analysed brane dynamics andtachyon condensation. We showedthat small dimensional branes havethe highest survival probability in agas of different dimensional branesand antibranes. We have alsoconstructed an unusual inflationaryscheme generated by tachyons in acertain large N limit.

M. Blasone, T. W. B. Kibble, J. Magueijo, M. Majumdar, L. Pogosian

We have played a leading role in thequest for methods for testing thehypothesis that the spectrum ofcosmic microwave bacground (CMB)fluctuations is Gaussian. With therelease of the first-year WMAP data,our group has provided a largenumber of data analysis tools for this.This work made use of advancedcomputing facilities supplied by theCOSMOS supercomputing consortium.We have also established an

important connection between non-Gaussianity and the possibility ofnon-trivial cosmic topology. Wesuggested that CMB fluctuationsmight have a thermal origin, andinvestigated the CMB power spectrumin scenarios with defects andinflation, and under quintessence.

The group was also instrumental inestablishing a framework for relatingthe theory and observations of avarying fine-structure constant. Thisranged from dilatonic to varying speedof light (VSL) theories; our work hasspurred an extensive continuinglitterature on both astronomical andlaboratory implications of this subject.

A highlight of our recent researchwas the discovery that varyingconstant theories may play animportant role in the quantisation ofgravity. Our work on the non-linearrealisations of the Lorentz group,and on deformed dispersionrelations, has triggered much subse-quent work on methods for imple-menting invariant quanta of spaceand time. It was shown that suchVSL quantum gravity theories mayexplain the presence of ultra highenergy cosmic rays, opening up thedoor to observational quantum gravity.In this context, we found that thebosonic string, subject to appropriatedispersion relations, does not needto have a tachyonic ground state.The black hole metric may run withenergy leading to a very differentspectrum for high temperatureHawking radiation, and with aconcomitant different endpoint forblack-hole evaporation.

Cosmology and Varying ConstantTheories

37

Undergraduate Teaching Director of Undergraduate Studies:Professor R. C. ThompsonSenior Tutor: Dr R. J. ForsythAdmissions Tutor:Professor W. G. Jones

The Blackett Laboratory, the largestPhysics Department in the UK,welcomes about two hundred newundergraduate students each year.We offer three year and four yearundergraduate degree programmesdesigned to match the pre-universityexperience of students from the UK,Europe and overseas. These degreeprogrammes lead to either the BScor the MSci degrees of the Universityof London (under special regulationsfor Imperial College).

There are six degree programmes,and the course structure allows easytransfer between most of theprogrammes in the early years.

Three Year Programmes

BSc Physics

BSc Physics with TheoreticalPhysics

Four Year Programmes

BSc Physics with Studies inMusical Performance

MSci Physics

MSci Physics with a Year inEurope

MSci Physics with TheoreticalPhysics

The Department also offers a fouryear BSc in Physics with a Year inEurope, but students are not normallyadmitted to this programme in Year 1.

The Department aims to provide allstudents on all degree programmeswith courses of the highest quality,giving them the opportunity to develop

their knowledge and understandingof Physics to a level which equals orexceeds that offered by any otheruniversity in the UK. We have recentlycompleted a major review of ourprogrammes to ensure that they areup-to-date and meet changingexpectations regarding international(particularly European) standards.The Departmental Staff/Studentcommittee is very active and makesan important contribution to thedesign of the curriculum and toimprovement in teaching.

All programmes start with a firmfoundation in core physics andmathematics followed by a broadand flexible range of options in thelater years. In the first three years,students receive tutorials in groupsof four from academics and otherresearchers. Courses are lecturedby experts in the field, and thebreadth and depth of researchactivity in this large departmentenables us to give studentsknowledge of the frontiers ofresearch in a wide range of special-ities in physics. The departmentwas one of only three in the wholecountry to receive the top grade of6* in the 2003 Research AssessmentExercise. It also has a teachingquality assessment of ÔexcellentÕ.The lecturers are drawn from ournine internationally recognisedresearch groups:

¥ Astrophysics¥ Condensed Matter Theory¥ Experimental Solid State ¥ High Energy Physics¥ Photonics¥ Plasma Physics¥ Quantum Optics and Laser

Science¥ Space and Atmospheric Physics¥ Theoretical Physics.

We also draw on expertise in otherdepartments to offer Mathematicsand Biophysics courses. Final yearprojects are offered in all theseresearch areas, providing an oppor-tunity for students to work alongside

academic staff, research fellows,research assistants andpostgraduate research students.

Broadly speaking, students aimingfor a career as a professionalphysicist or wishing to understandphysics at the frontiers of researchshould follow the MSci programmeboth for the additional content andalso for the opportunity to developprofessional skills and undertake amajor project. The MSci is thenormal route to a PhD. The BSc isaimed at a wide variety of studentswho wish to follow careers outsidespecialised research. Manyemployers value the numeracy andproblem-solving skills of physicists.For example, many physicsgraduates find their degree anexcellent platform for a career infinance. Some students choose thethree year BSc as a rapid and lessextended route into careers basedon physics in industry and publicservice. Others aim for a researchcareer in physics by taking the BScfollowed by a specialist MSc.

Courses in the first year cover:-

¥ Electricity & Magnetism¥ Electronics¥ Mechanics ¥ Quantum Physics¥ Relativity¥ Structure of Matter¥ Vibrations & Waves¥ Professional Skills I¥ Mathematics I¥ Mathematical Analysis¥ Physics Laboratory I¥ Physics Short Experiments and

Project I

Weekly seminar groups in the firstyear include group projects, devel-opment of problem solving skills,and exploration of research articles,web sites and research data.For most students, the first year

The Degree Programmes

MSci or BSc?

The First Year

http://www.imperial.ac.uk/physics/courses/ug

38

practical class consists of sessionson optics, electronics and computingof four weeks each. In the First andSecond Years we teach computerprogramming in C++, a valuable skillwhich is attractive to future employers.Students then choose betweenMathematical Analysis and morelaboratory work. For those choosinglaboratory, four weeks are spent onshort experiments designed tocomplement the first year physicslectures. The majority of studentsthen carry out a six week projectworking in small groups supervisedby active researchers. The projectsculminate in two open days on whichstaff, other students and sixth-formers view poster presentationson the projects.

Second year core courses cover:-

¥ Electromagnetism¥ Electrons in Solids¥ Optics¥ Quantum Mechanics I¥ Applications of Quantum

Mechanics¥ Statistical Physics¥ Statistics of Measurement¥ Thermodynamics¥ Mathematics II¥ Professional Skills II¥ Physics Laboratory II

BSc and MSci Physics studentschoose a Level 2 option from:-

¥ Sun, Stars & Planets¥ Physics Applied to Medicine¥ Mathematical Methods¥ Language

Second year laboratory work includesexperiments on Spectroscopy,Diffraction & Holography, Interferometry,Waves & Propagation, Radioactivity,Solid State Physics, OperationalAmplifiers and Computing. Emphasisis placed on the development of arange of experimental techniques aswell as more general professionalskills such as writing reports,keeping a laboratory note book, andassessment of experimental errors.

All BSc and MSci Physics studentstake core courses in:-

¥ Nuclear & Particle Physics¥ Solid State Physics¥ Atomic & Molecular Physics¥ Professional Skills III¥ Physics Laboratory III

BSc candidates have to complete aproject, which may be laboratorybased or theoretical.

MSci and BSc candidates take theComprehensive Papers (see below),and complete their third year with aselection of Level 3 options. Themore theoretical physics lecturecourses are marked with a (T)

¥ Advanced Classical Physics¥ Astrophysics¥ Dynamical Systems & Chaos (T)¥ Foundations of Quantum

Mechanics (T)¥ Group Theory (T)¥ Instrumentation¥ Lasers, Optics & Holography¥ Molecular Biophysics¥ Plasma Physics¥ Statistical Mechanics (T)

Students on Physics with TheoreticalPhysics courses replace LaboratoryIII with an extra theoretical option.All students may choose up to oneLevel 2 option (see above) and upto one Level 4 option (see below).They may also include one of thefollowing courses provided by theHumanities Programme andBusiness School:-

¥ Accounting¥ Art & nature¥ Communicating science: The

public & the media¥ Controversies & ethical dilemmas

in science & technology¥ Creative writing¥ European history (1870-1989)¥ History of medicine¥ History of science¥ History of technology¥ Language¥ Macro-economic policy¥ Modern literature & drama¥ Music & western civilisation

¥ Philosophy¥ Politics¥ The Roman empire¥ Science, culture & display

In their fourth year MSci studentscomplete a major project with aresearch group. This gives studentsan opportunity to get to grips with anextended project that lasts the wholeyear and relates to current researchactivities. In some cases, the projectresults in the publication of a researchpaper. Under the guidance of alecturer, students learn how to setgoals and plan their work to achievethem. Reading begins at the end ofYear 3 for a literature survey to bepresented at the start of Year 4.Thereafter students learn to designan experiment, formulate new experi-mental results or develop computersoftware, and to present their resultsin oral and written presentations.

The project is coupled to the ResearchInterfaces course which developsprofessional skills. This courseexplores the subjects of projectmanagement, written communication,financial management and spokencommunication, culminating in agroup business proposal. Anotheraim is to give students a workingknowledge of the vocabulariesrelating to research in universities,business and industry.

MSci students choose a selection ofLevel 4 options, and may study oneLevel 3 option (see above). TheLevel 4 options are

¥ Atmospheric Physics¥ Biophysics of Nerve Cells &

Networks ¥ Computational Physics (T)¥ Cosmology ¥ Device Physics¥ General Relativity¥ Laser Technology¥ Optical Communications¥ Particle Physics (T)¥ Quantum Coherence in Solids (T)¥ Quantum Field Theory (T)¥ Quantum Optics ¥ Space Physics ¥ Unification (T)

The Third Year

MSci Fourth Year

The Second Year

39

Students who choose to follow thisfour year MSci programme concen-trate on the more theoreticaloptions. In their first year they takean extra formal MathematicalAnalysis course instead of projectwork and in their second year theMathematical Methods option. InYear 3 these students takeAdvanced Classical Physics insteadof laboratory. The fourth yearproject is theoretical and studentstake a specified number oftheoretical options.

The MSci in Physics with a Year inEurope is of four years duration, thethird year being spent at a hostuniversity in continental Europe.Year in Europe students havederived great benefit and enjoymentfrom this opportunity to widen theirexperience. They usually go toEurope on ERASMUS/SOCRATESexchange programmes.

Students are visited twice duringtheir year abroad by a member ofstaff who normally is very familiarwith the host country and university.

Students carry out a researchproject in a research group. Theyare assessed on their written projectreport, a report from their supervisor,and an oral presentation in the hostlanguage.

In addition to the research project,students attend physics lecturecourses and sit examinations,written or oral, in the host language.As preparation for their year abroadthey take language courses in boththeir first and second years and arerecommended to take MathematicalMethods in their second year.

In their fourth year, MSci Year inEurope students sit theComprehensive Papers, takeNuclear and Particle Physics, SolidState Physics and Nuclear &Particle Physics, together with arange of options drawn from the

third and fourth year programmesincluding the Research Interfacescourse. The research projectcompleted abroad counts as theirMSci project.

We have established links with hostuniversities in France, Switzerland,Germany, Italy and Spain. Theseare: Universit� de Paris XI (Orsay),Ecole Sup�rieure de Physique et deChimie Industrielles (Paris), InstitutNational Polytechnique de Grenoble,Ecole Polytechnique F�d�rale deLausanne, Universit�t Erlangen-N�rnberg, Universit�t Freiburg,Universit�t Hamburg, Universit�tHeidelberg, Universit� degli studi diPadova, Universit� degli studi diTrento, Universitat de Valencia,Universidad de La Laguna (Institutode Astrof�sica de Canarias), andUniversidad de Cantabria(Santander).

Each of these universities has highstanding and extensive researchactivity. Some have exceptionalfacilities in particular research fields.

For example, La Laguna is excellentfor Astrophysics because of the sitingof many astronomical telescopes inthe Canary Islands. Imperial alsohas formal links with the IDEALeague Universities of Delft, Aachenand ETH Zurich.

The musical life of Imperial Collegehas always been strong and manyphysics students have demonstratedhigh ability in musical performance.The joint degree programme withthe nearby Royal College of Musicis for physics students who can alsoreach the RCMÕs stringent admissionstandards in musical performance.This programme provides studentswith a high quality honours BScqualification in physics while providingmusical training to the highest inter-national standards. The musiccomponent consists mainly in highlevel performance tuition by theProfessors of the Royal College ofMusic but also includes stylistic andhistorical studies. The Imperial

MSci Physics with Theoretical Physics

The Year in Europe Programme

S P A I N

FRANCE

UNITEDKINGDOM

ITALY

Year in EuropeHost Institutions

IDEA League

Grenoble

Valencia

La Laguna(Tenerife)

Santander

Orsay

ESPCI

Trento

Karlsruhe Erlangen

Lausanne

Padova

Freiburg

HamburgDelft

Aachen

SWITZERLAND

GERMANY

Zurich

Physics with Studies in MusicalPerformance

College Director of Music is activelyinvolved with this course. Studentson this programme have givenpublic recitals, performed asconcerto soloists, and won nationalcompetitions such as the BBC Radio2 Young Musician of the Year.

Our degree programmes contain amost valuable and unique component:the two comprehensive examinationpapers. These carefully constructedpapers are designed to test ourstudentsÕ ability to apply the corephysics taught in earlier years of thecourse to new situations. To do well,students need to gain an overviewof the whole of physics, and to seelinks and similarities between differentareas. Students are prepared forthese examinations through specialtutorials to develop these analyticaland problem solving skills, which areso important for a practising physicist.Most candidates complete thesepapers in their third year.

Applications for our undergraduatecourses are received through theUCAS system from all parts of theworld although most are from theUK. We wish to encourage applica-tions from all sectors, particularlyfrom areas traditionally under-repre-sented in higher education and fromother European countries. We arelooking for students of high abilityand motivation with the potential todo well on our courses. Offers ofplaces are conditional on achievinghigh grades in physics and mathe-matics at A-level and in a thirdsubject. The average of the gradesof students admitted is significantlyabove AAB (for the best 3 A-levels).We also admit students offering theInternational and EuropeanBaccalaureate, FrenchBaccalaureate, German Abitur, USAdvanced Placement examinationsand school leaving qualificationsfrom many other countries.

The percentage of women under-graduates admitted onto ourprogrammes has steadily increased

over recent years and in 2002 wasover 26%, which significantly exceedsthe national average for physics.This increase has been helped bythe College's ÔtasterÕ courses calledWISE (Women into Science andEngineering) which we operate inJuly each year.

Our students have wide interestsand abilities, particularly in music,the arts and sports, as well as beingamong the most talented in the landin physics. They go on to a widevariety of careers after graduationand a recent European wide surveyhas indicated that their rating of boththe employment potential of theirdegree and of the quality of theiruniversity experience are muchhigher than the European average.

All applications receive carefulattention and those applicants thatappear to be well suited to ourcourses are invited for a visit andinterview. These visits take place insmall groups between earlyNovember and early March andconsist of a tour of the campus,usually including a Hall of Residence,guided by an undergraduate,followed by a meeting with theAdmissions Tutor or one of hiscolleagues on the admissions team.This is designed to give applicantsinformation about the courses andthe facilities and also about life inImperial College and London. Thereis then a tour around the departmentfollowed by a short individualinterview. The latter helps us to getto know the student as an individualand is mainly concerned withinterests and motivation. It alsoenables applicants to raise questionsof particular interest to them.

Our high international profile ismanifested in many ways, not leastthrough our membership of severalstrategic alliances with major univer-sities in Europe (e.g. CLUSTER andthe IDEA League). In addition aboutthirty students from universitiesthroughout Europe and further afieldcome each year to study in theDepartment for selected final yearcourses and laboratory work. Mostcome under ERASMUS/SOCRATES

exchange student programmes.These Occasional Students, andthose European and Internationalstudents enrolled on our three andfour year degree programmes,greatly enhance the rich cultural andnational diversity of the Department.

School liaison is a high prioritywithin the Department, and we offervisits to schools and Òguided toursÓ.We also offer places to a number ofschool students undertaking workexperience training. We haveextended our reach geographically:for example, Physics has beenfeatured in the annual ImperialCollege recruitment visit to HongKong.

The Department, in association withthe College and the University ofLondon, has an extensive range ofout-reach programmes. These arefree and are designed to introducephysics to potential undergraduates.The most popular is the Open Day,focussed around a display by FirstYear students of their project work,and held around the third week ofJune. There are also variousMasterclasses held at various timesduring the year. The highly populartwo-day Women in Science andEngineering courses, held inJune/July, are specifically designedto encourage women students toconsider a degree course in one ofthe science or engineering disciplines.

40

The Comprehensive Papers

Undergraduate Admissions

Schools Liaison

41

Director of Postgraduate Studies:Dr Julia Sedgbeer

The Physics Department is one ofthe most prestigious postgraduateschools in Physics in the UK. In termsof research it uniquely covers themost comprehensive range ofimportant experimental andtheoretical research fields. Theseextend from astronomy, space andplasma physics to high energy,theoretical and atomic physics. Solidstate, laser physics, applied opticsand photonics have wide applications,while fields such as quantum infor-mation theory may lead to excitingnew applications. There are closelinks with the biophysics researchgroup (part of the Department ofBiological Sciences), which is alsohoused in the Blackett Laboratory.There are many examples of interna-tional and industrial collaborationinvolving our nine research groups.There are also interdisciplinary centreswhere researchers from differentgroups or from different Departmentscollaborate closely to benefit from eachotherÕs expertise. The Department hasextensive facilities and a tremendousrange of research topics available topostgraduate research students.

Information about the research beingundertaken in the particular groupsand centres can be found under theirsections elsewhere in this report;further details can be obtained fromthe individual Heads of Group (seepage 53).

The Department provides facilitiesand supervision for students toengage in research work leading toa higher degree of the University ofLondon (MPhil or PhD), and to theDiploma of the Imperial College (DIC).About 60 postgraduate researchstudents join the Blackett Laboratoryeach year, the majority being UKstudents with about 25% from otherEU countries and about 15% fromoverseas. The normal qualificationfor acceptance for research trainingis a first or second class honours

degree in Physics or a related subject.The usual length of registration for aPhD degree is three years.

In addition to research training, theDepartment offers postgraduatetaught courses leading to the MScdegree of the University of Londonand the DIC. The Department offerstwo MSc courses: Optics andPhotonics and Quantum Fields &Fundamental Forces. Further detailsof these MSc courses are given below.

The Graduate School of Engineeringand Physical Sciences(www.imperial.ac.uk/gradeps/) hasbeen established to develop andenhance the academic experienceof graduate students at the College.It provides training programmes andworkshops in professional and otherskills, undertakes quality assuranceof graduate programmes, organisesevents, such as guest lectures andsymposia, and promotes careeropportunities for graduate students.

Very few institutions world-wide areable to offer such a

wide range of opportunities inpostgraduate physics. Further infor-mation can be found in thePostgraduate Study in Physicsbooklet, atwww.imperial.ac.uk/publications/pgb/General information about graduatestudies at Imperial College Londoncan be seen atwww.imperial.ac.uk/pgoptions.

The MSc course in Optics andPhotonics has been running in itspresent form since October 2001and draws on the skills of staffactively involved in optics research.The title reflects the fact that thecourse covers both the traditionalareas of optics, which are of keyimportance to the application ofoptical techniques, and the importantareas of photonics, notably opticalcommunications and laser physics.The course aims to provide theprofessional skills in optics that arein demand by industry andacademia.

Postgraduate Studies

MSc in Optics and Photonics

http://www.imperial.ac.uk/physics/research/pg/

There are a large number ofemployment opportunities in opticsand photonics throughout the UKand the rest of Europe, not only inoptical communications but also inmany other areas of applied photonics.

The main components of the 12-monthMSc Optics and Photonics courseare lectures, laboratory experimentsand a fourÐmonth project. In the firstterm, there are four Foundationlecture courses in Information andTelecommunications, Imaging, Lasers,and Optical Measurement and Devices.In addition, there are sessionsdedicated to the development ofprofessional skills. There are occasionalseminars on the application of opticstechnology in industry, together withseminars on research and developmentin universities and industry. In thesecond term, a number of optioncourses are offered, including OpticalFibres, Optical Communications,Optical Design, Optical DesignLaboratory, Optical Fibre Sensors,Laser Optics, Laser Technology, andOptical Displays.

The laboratory experiments cover awide range of subjects and arespread over approximately 54 half-days in the first and second term,teaching key laboratory skills andtechniques.

The project lasts from mid-May tomid-September, and many projectscan be carried out in industry.Examples of recent projects are · A new method of producing

unidirectionality in solid-state ringlasers

· Polymer/nanocrystal blends forsolar cells,

· Femtosecond pulse shaper usinga spatial light modulator,

· Adaptive optics for the human eye,

· MEMS based digital filter,

· Optical modelling and optimisationof organic LED structures, and

· Fluorescence lifetime imagingapplied to microscopy.

There are a significant number ofEPSRC funded places for suitablyqualified UK students. Funding is

also available to cover the fees forsuitably qualified students fromother EU countries.

The Theoretical Physics Group runsthis very successful MSc course,attracting around 15 students annually.It is normally a one-year course butcan also be taken part-time over twoyears. A series of lecture coursesoccupies the year up to May andstudents spend the summer on aproject leading to the writing of adissertation. The course is intendedto bridge the gap between under-graduate-level work and the researchfrontier in theoretical physics. Manysuccessful students have gone on todo a PhD either at Imperial CollegeLondon or at another major university.Unfortunately, no financial support isavailable for students attending thecourse.

The lecture courses currently beingoffered are:

Compulsory lecture courses:Quantum electrodynamicsUnificationAdvanced Quantum Field Theory

Optional courses:SupersymmetryCosmology and Particle PhysicsTopics in Classical and Quantum GravityString TheoryDifferential GeometrySpecial Topics (short specialist courses on topics of current interest)

Available undergraduate courses:Foundations of Quantum TheoryGroup TheoryDynamical Systems and ChaosGeneral Relativity

Courses are offered subject to staffavailability; certain courses may notbe offered in a given academic year.

Students are assessed by examina-tions and a project dissertation. Theexaminations are on the compulsorycourses and on four optional courses,which may include up to two under-graduate options. Examinations onall the courses are held in May.There are also informal tests on thecompulsory courses in January.

MSc students are also encouragedto attend the regular weekly seminarsat which visiting speakers present

recent research results, as wellas internal seminars

by researchstudents.These

aresupple-

mented byan inter-

Collegiateprogramme of

weeklyseminars on

string theoryand related

subjects.

42

MSc in Quantum Fields andFundamental Forces

43

L. Clewley ÒDetermine the Mass ofthe Milky Way Using Blue HorizontalBranch StarsÓSupervisor: Dr S J Warren

J. V. Dawson ÒZeplin III: A Two-Phase Xenon WIMP DetectorÓSupervisor: Prof. T J Sumner

D. C. R. Davidge ÒDevelopment of aTwo Phase Xenon Detector for usein Direct Dark Matter SearchesÓSupervisor: Prof T J Sumner

L. E. Harley ÒObservation andOutflow Modelling of LuminousCataclysmic Variable StarsÓSupervisor: Prof. J. E. Drew

K. Kolokoutsas ÒMCW 297, ACase Study of a Massive YoungStellar ObjectÓSupervisor: Prof. J E Drew

S. K. Mattila ÒSupernovae asProbes of their Host Galaxies andCircumstellar Environments: SearchStrategies in Nuclear Starbursts andSpectroscopy of the SN 1987A CSMÓSupervisor: Prof. W P S Meikle

A. J. Bennett ÒA Study of InGaAs/GaAs Quantum Dots and GaInNAs/GaAs Quantum Wells for Opto-electronic Applications at 1300 nmÓSupervisors: Prof G Parry & Dr RMurray

A. J. B. Borak ÒOptical Studies ofThermal and Electronic Properties ofQuantum Cascade LasersÓSupervisor: Prof. C C Phillips

D. B. B. Bushnell ÒOptimisation ofStrain-Compensated Multi-QuantumWell Solar CellsÓSupervisor: Prof. K W J Barnham &Dr J Zhang

D. T. D. Childs ÒProperties andDevice Applications of 1.3mmemitting InAs/GaAs self AssembledQuantum DotsÓSupervisor: Dr R Murray

R. S. Ferguson ÒCharacterisation ofSilicon-Germanium Heterostructuresby Kelvin Force MicroscopyÓSupervisors: Prof. B Joyce & Dr KFobelets (Electrical Engineering)

D. G. Gevaux ÒSpectroscopic Studyof Mid-Infrared Light Emitting DiodesÓSupervisor: Prof. C. C. Phillips

J. W. Gray ÒResonant Cavity LightEmitting DiodesÓSupervisor: Prof. G Parry

A. D. Hartell ÒSurface Segregation ofAs During the Epitaxal Growth of SiÓSupervisor: Dr J Zhang

H. M. Liem ÒRaman Spectroscopy onConjugated Polymers-Effective Probeof Molecular Orientation and PhaseTransitions in Conjugated PolymersÓSupervisors: Prof. D D C Bradley &Dr P Etchegoin

S. Malik ÒTuning of Optical Propertiesof INAS/GAAS Self-AssembledQuantum DotsÓSupervisor: Dr R Murray

C. L. Olson ÒCharge Accumulationand Recombination in Nano-Crystalline Metal Oxide ElectrodesÓSupervisor: Dr J Nelson

R. Pacios ÒOrganic PhotovoltaicCells and Photodiodes Based onConjugated PolymersÓSupervisor: Prof. D D C Bradley

D. Poplavskyy ÒHole Injection andTransport in Organic SemiconductorsÓSupervisor: Dr J Nelson

E. P. Corrin ÒDevelopment of DigitalReadout Electronics for the CMSTrackerÓSupervisor: Prof. G Hall

J. R. M. S. Goncalo ÒMeasurementof the high-Q2 Neutral Current DeepInelastic Scattering Cross Sectionswith the ZEUS detector At HERAÓSupervisor: Dr K R Long

R. D. Hill ÒA Measurement of Rb atLEP2 with the ALEPH DetectorÓSupervisors: Dr J K Sedgbeer &Prof. D M Websdale

P. N. Martin ÒMeasurements ofAtmospheric Trace Gasses UsingOpen Path Differential UVAbsorption Spectroscopy for UrbanPollution MonitoringÓSupervisors: Dr J F Hassard & Dr RToumi

E. A. Noah Messomo ÒRadiationand Temperature Effects on theAPV25 Readout Chip for the CMSTrackerÓSupervisor: Prof. G Hall

M. Petteni ÒThe Jet Response andthe Search for the Higgs Boson inthe Channel ZH ->e+e- bbbar withthe Df DetectorÓSupervisor: Dr G J Davies

S. A. Rutherford ÒColourReconnection Studies at LEP2 withthe ALEPH detector and DataReduction Algorithms for the CMSElectro-Magnetic CalorimeterÓSupervisor: Dr C Seez

B. M. C. Simmons ÒRing ImagingCherenkov Counters for LHCbÓSupervisor: Prof. D M Websdale

L. Bollini ÒCharacterisation ofSemiconductor Optical AmplifiersThrough Bias Current ModulationÓSupervisor: Dr M W McCall

P-A. Champert ÒHigh PowerMaster Oscillator Powerful FibreAmplifiers for FrequencyConversionÓSupervisor: Prof J R Taylor

C. W. Dunsby ÒWide-Field Coherence-Gated Imaging Techniques IncludingPhotorefractive HolographyÓSupervisor: Prof. P M W French

D. S. Elson ÒDevelopment ofUltrafast Laser Technology and itsApplication to Fluorescence LifetimeImagingÓSupervisor: Prof. P M W French

S. E. D. Webb ÒDevelopment andApplication of WidefieldFluorescence Lifetime ImagingÓSupervisors: Prof P M W French &Dr M J Lever (BAMS)

Optics - Photonics

Astrophysics

PhD Degrees awarded in theDepartment in 2003

High Energy Physics

Experimental Solid State Physics

44

M. P. Anscombe ÒNonlinear Opticswith Atomic CoherenceÓSupervisor: Prof. J P Marangos

R. J. Blackwell-Whitehead ÒHighResolution Fourier TransformSpectrometry of the Spectrum ofNeutral ManganeseÓSupervisors: Prof P L Knight & Dr JC Pickering

I. Fuentes Guridi ÒEntanglementand Geometric Phases in Light-Matter InteractionsÓSupervisors: Dr V Vedral & Prof. P LKnight

J. L. K. Koo ÒLaser Cooling andTrapping of CA+ Ions in a PenningTrapÓSupervisors: Prof. R C Thompson &Dr D Segal

H. F. Powell ÒQuantum Optics WithA Single Trapped IonÓSupervisors: Prof. R C Thompson &Dr D M Segal

J. Rogel-Salazar ÒAspects of Bose-Eisntein Condensation and BesselBeam ResonatorsÓSupervisor: Prof. G H C New

J. Sudbery ÒStudies of LaserCooled Calcium Ions in the Penningand Combined TrapsÓSupervisors: Dr D M Segal & Prof. RC Thompson

D. R. Symes ÒHigh Intensity LaserInteractions with Extended AtomicCluster and Microdroplet MediaÓSupervisor: Dr R A Smith

B. K. Tregenna ÒManipulation ofQuantum Information in DecoherentEnvironmentsÓSupervisor: Prof P L Knight

J-W Ahn ÒInvestigations of theBoundary Plasma in the MASTTokamakÓSupervisor: Dr M Coppins

A. Ciardi ÒModelling of HypersonicJets in Wire Array Z-PinchExperimentsÓSupervisor: Dr J P Chittenden

H. M. Davies ÒThe role of finitelarmor radius (FLR) in instability inthe compressional Z-pinchÓSupervisor: Prof M G Haines

P. B. Jones ÒAn ExperimentalInvestigation into Tokamak edgeMHD BehaviourÓSupervisor: Dr M Coppins

J. G. Ruiz Camacho ÒPlasmaDynamics of two-wire z pinchesÓSupervisor: Prof. M G Haines

J. M. Gloag ÒResearch into WeakInterplanetary Shock Waves usingthe Ulysses SpacecraftÓSupervisor: Prof. A Balogh

A. L. Hadley ÒNon-Linearitiesbetween Atmospheric Sulphur andSulphur EmissionsÓSupervisor: Dr R Toumi

G. Matthews ÒSensitivity of aGeostationary Satellite Radiometerto Scene and Detector Non-UniformitiesÓSupervisor: Prof. J E Harries

M. J. Owens ÒThe Role of CoronalMass Ejections in Space WeatherÓSupervisor: Prof. P J Cargill

A. C. Pagel ÒAnalysis of TurbulentIntermittency in the Heliospheric Magnetic Field using Ulysses dataÓSupervisor: Prof. A. Balogh.

G. Pettinato ÒInvestigation ofAtmospheric Trends andPeriodicitiesÓSupervisor: Prof. J E Harries

A. Rees ÒUlysses Observations ofMagnetic Clouds in the 3-DHeliosphereÓSupervisor: Dr R J Forsyth

J. I. S. Syroka ÒOn the Withdrawalof the Indian Summer MonsoonÓSupervisor: Dr R Toumi

N. S. Trasi ÒA Finite Element-Spherical Harmonics Model Appliedto Radiative Transfer inInhomogeneous CloudsÓSupervisors: Prof J D Haigh & Dr CDe Oliveira (Royal School of Mines)

R. E. Clark ÒVacua and interpo-lating solutions in supergravityÓSupervisor: Prof. K S Stelle

J. D. Fearns ÒFoundations ofQuantum Physics in SmoothToposesÓSupervisor: Prof. J C Isham

M. Ivin ÒTopics in Quantum FieldTheoryÓSupervisor: Dr T S Evans

E. Kavoussanaki ÒTopologicalDefects in the Universe and inCondensed Matter SystemsÓSupervisor: Dr R J Rivers

Optics - Quantum Optics and Laser Science

Space and Atmospheric Physics

Theoretical Physics

Plasma Physics

45

The following grants, valued atover £16.3 million, were initiatedduring 2003.

Imperial College TrustP M W French Nervous systemmediated hypersensitivity states -fluorescence microscopy

£2,663,267.00

Royal SocietyD J Waldram Royal Society Fellowship

£196,305.26

Royal SocietyI C F Mueller-Wodarg RoyalSociety Fellowship. £202,756.69

Royal SocietyC M Hull The Structure of M-Theoryand String Theory Dualities (RoyalSociety Wolfson Research MeritAward). £225,000.00

Royal SocietyM J Damzen Adaptive GainInterferometer £68,704.00

Leverhulme Trade Charities TrustD D C Bradley Triplets states inpolymer light-emitting displays

£36,098.00

Royal SocietyE A Hinds Royal Society USAResearch Fellowship (Dr ElizabethAnne Curtis ) £36,000.00

Leverhulme Trade Charities TrustM B Plenio Royal Society/Leverhulmetrust senior research fellowships

£32,239.00

Commission of EuropeanCommunitiesM B Plenio Quantum Properties ofDistributed Systems - ThematicNetwork. £18,000.00

Commission of EuropeanCommunitiesV Vedral Topological quantum infor-mation processing £101,281.00

Commission of EuropeanCommunitiesD M Segal Quantum Gates andElementary Scalable ProcessorsUsing Deterministically AddressedAtoms (QGATES) £1,560,000.00

Commission of EuropeanCommunitiesE A Hinds Quantum Gates andElementary Scalable ProcessorsUsing Deterministically AddressedAtoms (QGATES) £73,305.00

Commission of EuropeanCommunitiesE A Hinds Preparations and applica-tions of quantum-degenerate coldAtomic/ molecular gases

£85,788.00

European CommissionK W J Barnham A New PV WaveMaking More Efficient Use of theSolar Spectrum (FULLSPECTRUM)

£376,000.00

Matsushita Electric Works LtdJ Nelson Organic solar celldurability research £114,450.00

Qineti QT J Sumner Energetic particle shieldingand interactions software tool

£27,200.00

BP International LimitedD D C Bradley Organic Electro-luminescent Lighting £209,994.00

Molecular Vision LimitedD D C Bradley A low cost point-of-care test kit for microalbuminuria

£147,786.00

ShimadzuJ-P Connerade Detecting Mirrorproject £85,000.00

National Physical LaboratoryR C Thompson Cold trapped Ionsfor Quantum information processing

£52,320.00

AWE PlcR W Smith Plasma PhysicsLectureship £300,815.00

NPL Management LimitedL Cohen NPL student sponsorshipagreement £18,000.00

Particle Physics and AstronomyResearch CouncilT J Sumner Development onInertial Sensor Charge ManagementSystem for SMART2 (and LISA).

£90,869.00

Particle Physics and AstronomyResearch CouncilJ C Pickering AstrophysicalLaboratory Spectroscopy: Improvingthe atomic data for astrophysics byhigh resoultion Fourier TransformSpectroscopy £110,996.00

Particle Physics and AstronomyResearch CouncilJ E Drew Towards an under-standing of accretion on to Herbigand T Tauri stars £184,635.00

Particle Physics and AstronomyResearch CouncilC Paterson High AngularResolution Imaging £165,452.00

Particle Physics and AstronomyResearch CouncilA Balogh Post Launch operationssupport for the Rosetta PlasmaConsortium instruments at ImperialCollege £241,262.00

Particle Physics and AstronomyResearch CouncilJ E Kalkkinen M-Theory solutionsand geometry (PPARC Fellowship)

£120,394.00

Particle Physics and AstronomyResearch CouncilD I Britton GRIDPP ProjectManager Costs £82,012.00

Particle Physics and AstronomyResearch CouncilC Paterson A complete toolkit foradaptive optics. £341,658.00

Engineering & Physical ScienceResearch CouncilP T�r�k Polarisation coding in highdensity optical data storage

£89,378.00

Engineering & Physical ScienceResearch CouncilE A Hinds The UK cold atoms:Network UKCAN

£49,625.00

Engineering & Physical ScienceResearch CouncilG Parry Quantum Light EmittingDiode for Secure Comms.

£256,761.00

Research Grants

Engineering & Physical ScienceResearch CouncilL Cohen Novel Growth andOptimisation of the MagneticProperties of Sr2FeMo06 Thin Films.

£263,655.00

Particle Physics and AstronomyResearch CouncilS C Cowley Magnetic field gener-ation in astrophysical plasmas

£52,947.00

Engineering & Physical ScienceResearch CouncilJ W G Tisch Basic Technologies:Attosecond Technology - LightSources, Metrology andApplications. £1,012,726.00

Engineering & Physical ScienceResearch CouncilP L Knight Decoherence inQuantum Information Processing.

£208,058.00

Engineering & Physical ScienceResearch CouncilA J Campbell Reactive,Polymerisable Organic LightEmitting Diodes (RPOLED).

£299,587.00

Particle Physics and AstronomyResearch CouncilA Balogh Participation in theMagnetic Field Investigation on theVenus Express Mission.£107,562.00

Particle Physics and AstronomyResearch CouncilM K Dougherty MagnetometerInvestigation for Cassini SaturnOrbiter. £998,776.32

Engineering & Physical ScienceResearch CouncilA J Campbell Electrical AndOptional Studies of ConjugatedSemiconducting Polymers And TheirDevices. £123,255.00

Particle Physics and AstronomyResearch CouncilK Long Research and developmenton cooling of intense muon beamsand experimental demonstration ofmuon ionisation cooling

£23,018.00

Engineering & Physical ScienceResearch CouncilP T�r�k 100 Fold increase of optical

data storage capacity using singularbeams and multiplexing £104,541.00

Particle Physics and AstronomyResearch CouncilG Hall The CMS Experiment at theLarge Hadron Collider - Completionof the Detector and the Road toPhysics £118,336.00

Engineering & Physical ScienceResearch CouncilL Cohen Raman spectroscopy andellipsometry of potential spintronic(half metallic) Ferromagneticmaterials £21,100.00

Natural Environment ResearchCouncilH E Brindley Aerosols in theEarth's climate: studies of the spectralproperties, variability, and climaticeffects based on new satellite obser-vations £139,570.60

Engineering & Physical ScienceResearch CouncilR J Rivers Complex Extension ofQuantum Field Theory. £92,025.00

Particle Physics and AstronomyResearch CouncilE A Lucek Physics of Boundariesand Waves in Collisionless Plasmas

£226,725.00

Particle Physics and AstronomyResearch CouncilM Petteni Higgs Searches at theTevatron with D0: Including Methodsto Improve the Search Sensitivity

£100,548.00

Particle Physics and AstronomyResearch CouncilP J Dornan TIER-2 Technical Co-ordinator £26,898.00

Particle Physics and AstronomyResearch CouncilT J Sumner Galactic Dark MatterSearch at Boulby: Years 2003 to 2007

£1,123,834.00

Particle Physics and AstronomyResearch CouncilK S Stelle M-Theory, Cosmologyand Quantum Field Theory

£748,893.00

Engineering & Physical ScienceResearch CouncilJ R Taylor All-fibre ultrashot pulsesources £360,448.00

Engineering & Physical ScienceResearch CouncilM W McCall ComplexElectromagnetic Media - BeyondLinear Isotropis Dielectrics

£13,633.00

Engineering & Physical ScienceResearch CouncilJ B Pendry Metamaterials createnew horizons in electromagnetism

£154,793.00

Engineering & Physical ScienceResearch CouncilT G Rudolph Local and extended-party quantum informationprocessing £203,593.00

Engineering & Physical ScienceResearch CouncilJ B Pendry Metamaterials createnew horizons in electromagnetism

£459,832.00

Engineering & Physical ScienceResearch CouncilV Vvedensky Self-assembled lowdimensional semiconductor nanos-tructures £129,131.00

Particle Physics and AstronomyResearch Council E A Hinds Centre for the measure-ment of Particle Electric DipoleMoments: Imperial College site

£65,851.00

Engineering & Physical ScienceResearch CouncilE A Hinds Deceleration of coldmolecules £66,550.00

Engineering & Physical ScienceResearch CouncilJ F Sparks M-Theory and excep-tional holonomy £37,671.00

Stanford UniversityT J Sumner Flight chargemanagement for drs on smart2

£111,956.00

Sandia National LaboratoriesR W Smith Readership in experi-mental Z-pinch based high energydensity physics £409,566.00

University Of CambridgeL Cohen Enhanced Critical Currentsand Pinning in SuperconductingMgB2 by Chemical Modification

£107,335.00

46

47

Physics is an international science,and many aspects of our researchinvolve collaborations with colleaguesat institutions in the UK and throughoutthe world. These include:

Air Products and Chemicals Inc., USA

Anglo Australian Observatory, Australia

Arhus University, Denmark

Astrophysics Research Institute

British Petroleum International, UK

California Institute of Technology, USACentre dÕEtudes des Rayonnements Spatiaux (CERS), France

CERN

CNR-IFAC, Firenze, Italy

Complutense University, Madrid

Cornell University, USADelft University of Technology, The Netherlands

Donostia International Physics Center (DIPC), San Sebastian, SpainEcole Polytechnique Federale Lausanne (EPFL), FranceEidgenossische TechnischeHochschule (ETH), SwitzerlandEI Du Pont de Nemours andCompany, USA

Endoscan Ltd

ESA-ESTEC, Holland

European Southern ObservatoryFree University of Amsterdam, The Netherlands

Free University Berlin, Germany

Free University of Brussels, Belgium

Ghent University, Belgium

GKSS, Germany

Goddard Space Flight Center, USA

Graz University, Austria

Hadley Climate Research CentreHarvard Smithsonian Center for Astrophysics, USA

Harvard University, USA

Herriot Watt University

Hewlett-Packard Laboratories, USAHigh Altitude Observatory, USA

HRL Laboratories LLC, Malibu, USA

INAOE, Mexico

Institute for High Energy Physics,Russia

Institute for Space Research, Austria

Institute for Nuclear Physics, Bulgaria

Institute of Chemical Physics, Spain

Institute of Nuclear Research, RussiaInternational Space Science Institute,Switzerland

Isaac Newton Group, La Palma, SpainJet Propulsion Laboratory, USA

Kentech Instruments LtdKFKI, Budapest, Hungary

Kings College London

Los Alamos National Laboratory, USA

Lucent LaboratoriesMassachusetts Institute of Technology,USA

Matsushita Electric Works, JapanMax Planck Institute, Garching,GermanyMax Planck Institute, Heidelberg,GermanyMax Planck Institute, Kattenburg-Lindeau, Germany

MEMC Electronic Materials Inc., USAMerck Ltd, UKNASA Langley Research Center, USANational Institute Standards andTechnology, USA

National Physical Laboratory

National Solar Observatory, USA

NRL Washington, USAObservatoire de Nice, FrancePadua Observatory, Italy

Pennsylvania State University, USA

Perimeter Institute, Waterloo, Canada

Philips Research, The Netherlands

Pilsen University, Czech RepublicResearch Center of Crete, GreeceRoyal Meteorological Institute,Brussels, Belgium

Rutherford Appleton Laboratory

Sandia National Laboratory, USAScottish Environment and EnergyFoundation

Space Telescope Science Institute

Stanford University, USASteacie Institute for MolecularSciences, Canada

Stockholm Observatory, SwedenTechnical University ofBraunschweig, GermanyTechnical University of Denmark,Lyngby, DenmarkTechnical University of Vienna, Austria

Technion, Israel

THALES Paris, France

The AtlantIC Alliance

The Dow Chemical Company, USA

Trieste Observatory, Italy

UK Meteorological Office

UMISTUniversidad Aut�noma de Madrid,Spain

Universidad de Zaragoza, SpainUniversit� Louis Pasteur,Strasbourg, France

University College London

University of Arizona, USAUniversity of Athens, GreeceUniversity of Austin, USA

University of Bangor

University of Barcelona, Spain

University of Basilicata, ItalyUniversity of Birmingham

University of Bologna, Italy

University of Bonn, GermanyUniversity of Braunschweig,Germany

University of Bristol

University of Buenos Aires, BrazilUniversity of California Los Angeles,USAUniversity of California San Diego,USA

University of Cambridge

University of Chemnitz, GermanyUniversity of Cologne, Germany

University of Colorado, USA

University of Hampton, USA

University of Hertfordshire

University of Hawaii, USA

University of Kaiserslautern, Germany

University of Leeds

University of Leicester

University of Naples, Italy

University of Neuchatel, Switzerland

Collaborations

University of NewcastleUniversity of New South Wales,Australia

University of Nottingham

University of Oslo, Norway

University of Otago, New Zealand

University of Oxford

University of Paris XI, Orsay, France

University of Palermo, Italy

University of Potsdam, Germany

University of Reading

University of Rochester, USA

University of Salerno, Italy

University of Sheffield

University of Siena, Italy

University of Southampton

University of St Andrews

University of Strathclyde

University of Surrey

University of Sussex

University of Sydney, Australia

University of Texas at Austin, USA

University of Valencia, Spain

University of Wales, Aberystwyth

University of Warwick

University of Wurzburg, Germany

University of York

Washington University, St. Louis, USA

Weizmann Institute, Israel

Wellesley College, USA

We are members of a significantnumber of European Union andother collaborative programmes,including:

ACQUIRE, a European Uniontraining network AEOLOS, the assessment of theimpact of SF6 and PFC reservoirtracers on global warming

ALEPH experiment, CERN

ASTRO-F consortiumAustralian Network of Excellence on Atom InterferometryBasic Technology AttosecondProgrammeBritish Petroleum International (UK)Ð Imperial College Engineering forSustainable Development Programme

CMS collaboration

COCOMO, a Research TrainingNetwork on coherent control ofatomic processesConsortium for ComputationalQuantum Many-Body TheoryCOSLAB, an ESF Programme onCosmology in the LaboratoryD0 Consortium, Fermilab, USA

ELAIS surveyEPSRC Experimental and TheoreticalStudies of Electrical Transport inOrganic Electroluminescent DevicesProgrammeEPSRC Polymer BlendSemiconductors ProgrammeEPSRC Retinomorphic ImagingBasic Technology ProgrammeESF Network on Quantum InformationprocessingESF-QIT programme on QuantumInformation Theory and quantumcomputationEuropean Union training network onCold Quantum GasesFASTNET, a European Uniontraining network Framework VI, Nanotechnology;British Council/DAAD ARC programmeFERRUM project: oscillator strengthsfor astrophysics applicationsHERSCHEL SPIRE consortiumHITRAP, An Ion Trap Facility forExperiments with Highly-Charged IonsHYTEC, a CEC Framework V IHPNetwork

IR studies of nearby type II supernovaeISCOM, a EU Network on theInformation Society as a ComplexNetwork

ISD LINK (DTI/EPSRC)Late-time spectroscopy of type Iasupernovae

London Centre for NanotechnologyNANOFAB, a European Uniontraining network

PLANCK HFI consortium

POE, a European Community RTNPOWERPLAY, a CEC CSGprogramme projectUltrafast Photonics Collaboration(UPC IRC)Ultrafast spectroscopy of conjugatedpolymersSLAM, a programme on Future andEmerging TechnologiesSWIRE, the NASA SIRTF LegacySurvey

QUEST, a European Union IHPNetwork collaboration on QuantumOpticsQGATES, a European Union ISTNetwork collaboration on quantumgates for quantum computingQUBITS, an IST Network ondecoherence in atomic logicelementsQuICT, a UK EPSRC Networkcollaboration on quantum informationand coherenceQUIPROCONE, a European UnionIST Network of Excellence coordinatingbody on quantum informationprocessing throughout EuropeQUPRODIS, a Thematic Network onthe Quantum Properties ofDistributed quantum systemsSearch for supernovae in starburstgalaxiesSOLICE, Solar influences on Climateand the EnvironmentSpin Polarised Magnetics Oxidesnetwork and Spintronics NetworkStudies of SN 1987A at very latephasesSupIRCam, A tool for understandingthe IR light curves of type Ia SupernovaeThe host galaxies of high redshifttype Ia supernovaeThe Physics of Type Ia SupernovaExplosionsThe progenitors of massive, core-collapse supernovae

UKCAN, the UK cold atoms network

UK GridPP Project

UKIRT Infrared Deep Sky Survey

UK Mid-Infrared network

UK National Carbon Based

Electronics Consortium

48

Many aspects of the research in thedepartment have the potential forcommercial opportunities. Much ofour work requires the development oftechnologies to facilitate fundamentalscientific projects yet there is a growingrecognition that a number of thesetechnologies merit protection throughpatenting. The Department has awide range of commercial interactions.We collaborate with companies aspartners in large European projects,DTI Link projects, Basic Technology,etc. Ph.D students within the Departmentbenefit from direct sponsorship byindustry and EPSRC CASE awards.Companies support our researchdirectly and provide Ôin kindÕ support(such as loan of equipment, access tofacilities). We also have a good trackrecord of licensing our intellectualproperty and working with industryas consultants. In addition, theDepartment currently has 5 successfulspin out companies. Our technologydevelopment and commercial activitiesinclude the following:

AstrophysicsThe experimental part of Astrophysicsis dedicated to the development of0.1-100 keV particle detectors andassociated technology (high precisionultra high vacuum technology incopper, gas purification, charge/lightreadout technologies, positionreconstruction, cryogenics) for thedark matter project and charge controlsystems and associated technology(UV light sources, particle guns,satellite instrumentation) for thegravitational wave project. The Groupcollaborates with QinetiQ, CarloGavazzi Space (Italy) and the JetPropulsion laboratory (USA).

Condensed Matter TheoryThe Group has a wide-rangingresearch portfolio with a strategicfocus on materials for electronic andphotonic devices, and has developedtheoretical and computational expertisein the modelling of these materials.Many projects have direct relevanceto the next generation of technologies.These include the development of

new materials for the "perfect lens"in near-field optics, plasmonic andphotonic structures, nano-electro-mechanical devices, and the growthof thin films and quantum dots.Techniques include quantum MonteCarlo simulations, kinetic Monte Carlosimulations and density functionaltheory.

The Group has a close workingrelationship with BAE, Astron andAntenova and holds several patents.

Experimental Solid State PhysicsThe group develops technologiesacross a very broad range of areas.

Molecular electronic materials providea novel class of semiconductor withapplications in flat panel electrolumi-nescent displays and lighting, TFTarrays andmemory devices,imaging devicesand solar cells,optical amplifiers

and lasers, andmicroanalysissystems forchemical andbiological

detection. Air Products and ChemicalsInc, British Petroleum, BP Solar, DuPont, Matsushita Electric Works, Merckand Molecular Vision have directlyfunded research in the group during2002-2003. In addition, we have hadcollaborative projects with CambridgeDisplay Technology and Philips(CEC POWERPLAY), Covion GmbH,and The Dow Chemical Company.Consultancy has been undertakenfor both industrial corporations andventure capital organisations.

Finally, the group also has severalpatents in this technology area anda spin out company, MolecularVision Ltd, has been set up. Inorganic opto-electronic emitters,detects and modulators are beingdeveloped for use in the data andtelecomms areas. The work iscollaborative with Toshiba, Sharp,Zarlink, Bookham, TTP and IQE.Design and growth of single photonsources and long wavelengthdetectors is another active areausing InAs quantum dot technologyfor quantum cryptography andtelecomms applications. The work iscollaborative with Toshiba andBookham. In collaboration withQinetiQ, Bell Labs, and ThompsonCSF, quantum cascade lasers arebeing developed for optical commu-nications. We hold 3 patents in theseareas. Optical Products have fundedCASE studentships in novel inorganicphotovoltaics, an area where we holdthree patents. BP Solar fund our workinto novel inorganic photovoltaics andthin film silicon cells. As part of theEU Framework VI integrated projectÒFull SpectrumÓ we are collaboratingwith Nanoco and Solaronix.

NPL currently sponsor Ph.D students inSpintronics and in optical spectroscopyfor single molecular detection. NECIsupport our work in high mobilitynarrow gap semiconductors forhybrid sensor technology. In the areasof superconductivity and magnetismwe collaborate with QinetiQ, NPLand Oxford Instruments.

High Energy PhysicsThe Group has a long tradition oftechnology transfer, with anemphasis in advanced instrumen-tation and detector technologies,optoelectronics and biomedicalapplications but with interests in thefinancial, energy and general instru-mentation sectors. Group membershave filed about 28 patents in supportof their technology Ð more than CERN.Early work by David Binnie, JuliaSedgbeer and Ray Beuselinck led toa novel suite of software for gamma

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Technical Development, Intellectual Property and Commercial Interactions

camera production, which is nowadopted world-wide by a number ofindustrial groups.

The Group develops technology in arange of areas. Gamma-cameras,radiation hard electronic, silicon sensors,digital read out and control electronics,fibre-optic links and plastic explosivedetection (using diamond detectorsand fast neutron sources). The Grouphas developed a generic approachto ultra-high throughput genomics,proteomics, and health care diagnosticsfor DNA sequencing, protein mappingand ultrafast protein folding. Thistechnology has been adopted by anumber of biotech and pharmaceuticalcompanies and is being developedinto a generic discovery platformwith a wide range of applications indrug discovery and development,diagnostics, general molecularbiology in genomics and proteomics,and biological threat assessmentand mitigation.

The Group has a growing influencein Grid technologies, where there is aconvergence between high throughputsystems for biomedical applicationsand those pioneered for Tevatron andLHC areas. The EPSRC fundedÔDiscovery NetÕ (with Hassard co-PI,in collaboration with the Departmentof Computing (DoC)) seeks to applyHEP approaches to processing vastquantities of data to a range ofindustrial applications where thebandwidth, multiple source andvisualisation issues are closelyrelated (such as bio-informatics).

John Hassard has worked with GeoffRochester of Astrophysics in a novelrenewable energy system Ð tidalstream power. This uses several toolscommon to approaches common inparticle physics, most notably finiteelement analysis. Several munici-palities (most notably the City and

County of San Francisco) haveadopted this technology, together withsome major UK and non-UK utilities.

The Group has spun out a number ofcompanies (deltaDOT Ltd, DiamondOptical Technologies Ltd, HydroVenturiLtd among others), which have raisedfinance and are progressing theircommercial relationship with othercompanies, and with a large numberof UK, US and other companies inseveral sectors.

Laser ConsortiumOur technology is associated withdeveloping high intensity and ultrashort laser pulses. Theoreticaldescriptions of the effect of theseintense fields have led to technologythat can be used to produce micro-scopic optical structures by laserinduced modification (through multi-photon ionisation) of media. Theattosecond basic technologyprogramme promises to open upnew fields of ultra high time resolutionmeasurement in surface science etc.

Plasmas produced by interaction ofshort pulse lasers with sub wavelengthclusters are a promising source forx-ray generation at lithographicallyimportant wavelengths. They alsoproduce high energy density plasmasof interest for testing of numericalcodes. We currently have an ongoing collaboration including fundingfrom AWE in this area.

PhotonicsDirect support for our research intohigh-resolution imaging comes fromGlaxo-SmithKline and KentechInstruments. Scientific Generics plc,Kodak Ltd, Kentech Instruments Ltdand ICR/ Royal Marsen NHS Trusthave all supported CASE awards.ÔIn kindÕ support has come from OpticalInsights, Inc, LaVision Biotec GmbH,PicoQuant GmbH and KentechInstruments Ltd.

The Group, in the area of high powerlasers and nonlinear optics, holdsone patent on optical amplifyingdevices. Pilkington Optronics (nowThales) have supported CASE awardsand Ôin kindÕ support has come fromShell Research Labs, Spectra-Physics and Spectron Laser Systems.

The fibre laser programme includesdevelopment of MOPFA (MasterOscillator Power Fibre Amplifier)technology including development ofversatile compact seed sources,which are deployed together withhigh power, fibre-based amplifiers(Yb, Yb-Er and Raman) to generatehigh average power sources withversatile wavelength and pulseformats. The fibre work has long-standing collaboration and supportfrom the IPG Group of Companies

The Group has one spin out companyHoloscan UK Ltd funded through theUniversity Challenge Seed Fund.

Plasma PhysicsThe Group is engaged in researchinvolving the technology of highvoltage pulsed power and highpower lasers. We also work in thedevelopment of Òtable-topÓ sourcesof x-rays, neutrons and particle beamsfor technological applications. Inaddition, we have a researchprogramme into the development ofion thrusters for spacecraft propulsionand satellite positioning.

We have collaborations with anumber of external companies andorganisations which provide CASEawards and other support. Theseinclude UKAEA Culham, AWEAldermaston plc., QintetiQ, TitanPulsed Sciences Corp., Sandia

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National Laboratory, KentechInstruments Ltd, the Laboratory forLaser Energetics (University ofRochester), the Institute for LaserEngineering (University of Osaka) andthe Lawrence Livermore NationalLaboratory.

Quantum Optics and LaserScienceThe Group applies cutting edge lasertechnology to a broad range ofmeasurement and control problemsin basic physics research. The Centrefor Cold Matter has an ongoingcollaboration with the K. J. Leskercompany investigating transparentconductive films for polymers. Dr D.M. Segal and Prof. R. C. Thompsonhave ongoing collaborations with theNational Physical Laboratory (NPL)on ion trapping and the developmentof ultra-stable lasers. This includessupervision of students funded bythe NPL who carry out most of theirexperimental work there, but who areregistered as students at ImperialCollege.

Space and Atmospheric PhysicsThe Group develops magnetometers,light weight cryogenic systems, farinfra-red detector arrays, multi-instrument digital electronics andspectrometer designs for spacemissions. It also develops highresolution UV and VUV Fouriertransform spectroscopy particularlydetector arrays and beam splitters.The Group collaborates with UltraElectronics and SIRA as well as theMET office and the USA and FrenchNavy.

Theoretical PhysicsThe dominant part of the GroupÕsactivities lies in constructing theoriesof the fundamental nature of theuniverse (M-theory, quantum cosmology,brane-cosmology, astroparticle physics,etc.). None of these require thedevelopment of any technologies.However, subsidiary activities of theGroup may lead to novel applicationsof superconducting devices (throughthe ESF Cosmology in the Laboratory(COSLAB) programme), or haveimplications for the modeling of

commercial and industrial activity(through the EU The InformationSociety as a Complex System (ISCOM)network) or for the modelling ofcommercial products (e.g. financialderivatives).

An example of such subsidiary activityis the work of Dr M. Blasone todevelop and patent the "MetaPassword"system for secure access to acommunications network, based onbiometric data. He, and his partnersat the University of Salerno,developed a business plan forcommercialisation of this systemand it was entered in the UKResearch Councils Business PlanCompetition. It was one of only twosuch projects from Imperial to beaccepted into the final round ofcompetition. Students in the Grouphave developed various databasealgorithms and have formed acompany to exploit these ideas.

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Space PhysicsA Balogh, DIC, MScPhysicsK W J Barnham, PhDPhysicsA R Bell, MA, PhDExperimental Solid State PhysicsD Bradley, BSc, PhD, ARCS, FRSA, CPhys, FRSPhysicsP J Cargill, BSc, PhDAtomic and Molecular PhysicsJ-P Connerade, PhD, ARCS, DICPlasma PhysicsS C Cowley, BA, MA, PhDApplied OpticsJ C Dainty, PhDExperimental Particle PhysicsP J Dornan, BA, PhD, FRSPhysicsJ E Drew, BSc, PhDPhysicsP M W French, PhDPhysicsJ P Gauntlett BSc, PhDAtmospheric PhysicsJ D Haigh, DPhilPhysicsG Hall, BSc, PhDTheoretical PhysicsJ J Halliwell, BSc, PhD

Earth ObservationJ E Harries, BSc, PhDQuantum OpticsE Hinds, BA, DPhil, FRSPhysicsC M Hull, BA, PhD, FlnstPLaser PhysicsM H R Hutchinson, PhDTheoretical PhysicsC J Isham, PhD, ARCS

PhysicsW G Jones, PhD, ARCSQuantum OpticsP L Knight, DPhil, FRSTheoretical Solid State PhysicsK M Krushelnick BSc, MA, PhDPhysicsA Mackinnon, PhDLaser PhysicsJ Marangos, PhDPhysicsW P S Meikle, PhD, FRASNonlinear OpticsG H C New, DPhil Applied PhysicsG Parry, BSc, PhD, DICTheoretical Solid State PhysicsSir J B Pendry, MA, PhD, FRSExperimental Solid State PhysicsC C Phillips, PhDPhysicsM B Plenio, Dr. rer. nat AstrophysicsM J Rowan-Robinson, PhDPhysicsR W Smith, MA, PhD, DIC

PhysicsD J Southwood, BA, PhD, DICTheoretical PhysicsK S Stelle, PhD Experimental AstrophysicsT J Sumner, DPhilUltrafast Physics and TechnologyJ R Taylor, BSc, PhDPhysicsM J Thompson, BA, MA, PhDPhysicsR C Thompson, MA, DPhilPhysicsA Tseytlin, MS, PhDPhysicsT S Virdee, PhDTheoretical Solid State PhysicsD D Vvedensky, PhDPhysicsD M Websdale, PhD, ARCS

Dr. T C Bacon, BSc, PhDEmeritus Prof. D M Binnie, PhDEmeritus Prof. D D Burgess, MA, PhD, DICEmeritus Prof. I Butterworth, PhD, CBE, FRSProf. A D Caplin, MA, MSc, PhDEmeritus Mr. A E Dangor, BScProf. M G Haines, PhD, ARCS, FRCO, ARCMDr. H F Jones, BA, PhDEmeritus Prof. B A Joyce, DSc, FRSProf. T W B Kibble, MA, PhD, FRSProf. E Leader, BSc, MS, PhDProf. L B Lucy, BSc, PhDProf. R Newman, PhD, FRSProf. J J Quenby, BSc, PhD, DIC, ARCSDr. A P Thorne, MA, DPhil

PhysicsL F Cohen, BSc, PhDPhysicsM J Damzen, PhDHigh Energy PhysicsP D Dauncey, BA, DPhilSpace PhysicsM K Dougherty, BSc, PhDHigh Energy PhysicsC Foudas, MA, M.Phil, PhD PhysicsW M C Foulkes, PhDPhysicsJ F Hassard, PhDPhysicsS Lebedev, MS, PhDPhysicsK R Long, BSc, DPhilTheoretical PhysicsJ C R Magueijo, BA, PhDPhotonics PhysicsM W McCall, PhDPhysicsJ Nash, PhDPhysicsJ Nelson BA, PhDPhysicsR J Rivers, PhDLaser PhysicsR A Smith, BSc, PhD

Atmospheric PhysicsR Toumi, PhD, ARCSPhysicsV Vedral, BA, PhDPhysicsS J Warren, BA, PhD

D I Britton, BSc, MSc, PhDR G Burns, PhD J P Chittenden,PhD, DIC, BSc, CPhys, MInstPK Christensen, PhDM Coppins, PhDH F Dowker BA, MA, PhDT S Evans, BA, PhDR J Forsyth, BSc, PhDR Murray, BSc, PhD, K Nandra, BA, PhDJ K Sedgbeer, PhD, DICD M Segal, BSc, DPhilK Weir BSc, PhDJ Zhang, BSc, ARCS, PhD, DIC

A Beige, BSc, PhDH. E. Brindley, BSc, PhD D C Brody, BSc, MSc, PhDR S GarciaA Goussiou, BS, PhDT S Horbury, BSc, PhDA H Jaffe, MSc, PhDR Jesik, BSc, MSc, PhDE A Lucek, BSc, PhDI C F Mueller Wodarg, MSc, PhDC Paterson, BA, PhDM Petteni, PhDS V Popov, MSc, PhDT G Rudolph, BSc, PhDD J Waldram. BA, MA, PhD

A J Campbell, BSc, MSc, PhDG J Davies, BSc, PhDU Egede, BSc, PhDC N Guy, PhD R J Kingham, BSc, PhDD K K Lee, BA, PhDI Liubarsky, BSc, PhD, CPhys, MinstP, FRASV Moore, PhDZ Najmudin, BA, PhD M A A Neil, BA, PhDJ C Pickering, BA, MA, PhD, DICB Sauer, BA, PhDJ W G Tisch, BSc, PhDP T�r�k, DPhil, PhDY C Unruh, MSc, PhD

M E Barnett, BSc, BA, PhDD Cotter, BSc, PhD, DScR G Evans, BSc, PhD, FlnstPJ Gallop, BA, DPhilP Gill, BSc, DPhilI Grant, FRSR Hastie, BSc, MSc Sir M J Rees, MA, PhD FRSA D Sokal, AB, AM, PhDJ C Thompson, MA, PhD

Academic Staff (as of 31st December 2003)

Professors

Senior Research Fellows

Lecturers

Senior Lecturers

Readers

Advanced Fellows

Visiting Professors

Astrophysics Group Page 4Head of Group: Professor M Rowan-RobinsonTel: 020 7594 7530, Fax: 020 7594 7541, e-mail: [email protected]

Condensed Matter Theory Group Page 7Head of Group: Professor D D VvedenskyTel: 020 7594 7605, Fax: 020 7594 7604, e-mail: [email protected]

Experimental Solid State Physics Groupand Centre for Electronic Materials and Devices Page 10Head of Group: Professor K BarnhamTel: 020 7594 7565, Fax: 020 7581 3817, email: [email protected]

High Energy Physics Group Page 16Head of Group: Professor P J DornanTel: 020 7594 7822, Fax: 020 7823 8830, email: [email protected]

The Laser Consortium Page 19Director: Professor J P MarangosTel: 020 7594 7857 Fax: 020 7594 7714, email: [email protected]

Photonics Page 22Head of Group: Professor P M W French Tel: 020 7594 7706, Fax: 020 7594 7714, email: [email protected]

Plasma Physics Group Page 25Head of Group: Professor K KrushelnickTel: 020 7594 7635, Fax: 020 7594 7658, email: [email protected]

Quantum Optics and Laser Science Page 28Head of Group: Professor J P MarangosTel: 020 7594 7857 Fax: 020 7594 7714, email: [email protected]

Space and Atmospheric Physics Group Page 31Head of Group: Professor J E HarriesTel: 020 7594 7670, Fax: 020 7594 7900, e-mail: [email protected]

Theoretical Physics Group Page 34Head of Group: Professor K StelleTel: 020 7594 7826, Fax: 020 7594 7844, e-mail: [email protected]

Contacts

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