Volume-05, February 2003 PDF version (coming soon)

Contents ISP website bags award

ISP - Dutch collaboration

From editor's desk

Raman's bust installed in ISP

CELOS - Recognition where it is due

Conference news

Photonians- The Alumni Association

We hear that

From ISP Labs

In the limelight

Recent publications from ISP ISP website bags Golden Web Award The website of International School of Photonics,Cochin University of Science & Technology,(http://ww.photonics.cusat.edu) has won theGolden Web Award for the year 2003- 2004. Thesite which was launched in early 2002 containsinformation on the all round activities of theSchool as well as on the frontier areas ofPhotonics related research and development.

International Association of Webmasters andDesigners (http://www.iawmd.com/) to those siteswhose web design shows originality and contentshave achieved a level of excellence deservingrecognition. Founded in 1997 with internationalsupport, Golden Web Award that also carries acertificate of merit is a free service of theAssociation.

Home page of International School of Photonics

A website submitted for review to IAWMD is sentto the members whose opinions decide whether a

from powerful modern lasers can safely removematerial from a tooth without damaging thesurrounding area. Previous attempts to developthis technique have failed because they usedlonger-lasting laser pulses that heated andcracked healthy parts of the tooth. (A. Rode et. al., J. Appl. Phys., 92, 2153, 2002 Hollow core photonic crystal fibre raman laserLaser physicists in the UK have reduced thethreshold power needed for stimulated Ramanscattering by two orders of magnitude. The BathUniversity team says that the breakthrough -which exploits a low-loss, hollow-core photonic-crystal fibre filled with hydrogen - marks thebeginning of a new era in gas-based nonlinearoptics. (F Benabid et al., 2002 Science, 298, 399) Electrical pulses break light speed recordPulses that travel faster than light have beensent over a significant distance for the first time.Alain Hache´ and Louis Poirier of the University ofMoncton in Canada transmitted the pulsesthrough a 120-metre cable made from a coaxial'photonic crystal'. To create their cable, theCanadian researchers joined together five-metresections of coaxial cable with alternating electricalimpedance. They sent electromagnetic pulseswith frequencies between 5 and 15 MHz throughthe cable, and found that the group velocityreached 3 times the speed of light for frequenciesin the absorption band. This was remarkable incomparison with many existing informationsystems that are based on coaxial cables withdata speed of just two-thirds the speed of light.The achievement that utilized the back-reflectioncaused by impedance mismatch raise hopes thatdata could travel through electroniccommunications systems at almost the speed oflight. (A Hache´ and L Poirier 2002 Appl. Phys. Lett. 80518) A breakthrough in teleportation When physicists teleported photons for the firsttime in 1997, they had to destroy the photons tobe sure that the teleportation had beensuccessful. Now a team at the University of

site ultimately wins the award. The ISP websitethat has been awarded the Golden Web in theacademic institutions category went on air in 2002as part of the School's objective of reaching aworldwide audience with academic and researchprograms. Aimed at drawing the attention of theinternational scientific community to the activitiesof the department, the knowledge portal providedin the site is perhaps one of the largest onlineinformation sites. The site will sport the logo of the Golden WebAward in future which is a recognition accorded toa winning site by IAWMD. The award has provideda great boost to the site builder Mr. B.Aneeshkumar, whose latest inclusions to the siteare a home page dedicated to the Centre forExcellence in Lasers and Optoelctronic Sciences(CELOS) and a common mailing list comprisingthe faculty, students and administrative staff ofthe School.

Indo-Dutch Workshop on Current Trends inPhotonic Materials & Devices - A ReviewISP and International Collaboration

The Indo - Dutch workshop held during January14-15, 2003 at ISP gave an in-depth view of thepresent scenario of the Photonic materials anddevices that are being used worldwide in industrialas well as research fields. As part of its academic collaboration with theEindhoven Technical University in Holland underthe Dutch Government's Program of InternationalCo-operation in Higher Education (MHO), theInternational School of Photonics (ISP) hasconducted many conferences and workshops infrontier areas of Photonics related research overthe past few years. In the New Year, theinternational activities of the department wereheralded by the 'Indo-Dutch Workshop on CurrentTrends in Photonic Materials and Devices' held inmid-January at the ISP building.

Prof. V. M. Nandakumaran speaks during the

inauguration of the Indo-Dutch workshop

This was also the first academic activity to beorganized by the School in its own building in theUniversity campus. Attended by over 40 delegatesfrom across the country, the conference providedan arena for young researchers to present postersand hold discussions with experts drawn fromvarious research laboratories within India andfrom the Technical University of Eindhoven, TheNetherlands.

Vienna has managed to teleport photons withoutdestroying them. Jian-Wei Pan and colleagues believe that their method could be thenext step towards long-distance quantumcommunication. In a standard teleportationexperiment, a laser is directed at a crystal withnonlinear optical properties. Occasionally thephoton will be "down-converted" into two lowerenergy photons, and sometimes these photonswill have their polarizations entangled whereinone of them is vertically and the otherhorizontally polarized. By using a filter to reducethe intensity of the photons that are going to beteleported, the researchers were able tosignificantly reduce the number of spuriousdetection events. The Vienna team could be 97%certain that the state had been teleported to aphoton without actually having to detect it. Such ahigh accuracy means that the teleported photonscould be used in "quantum repeaters" for longdistance communication. The team now hopes tocombine these results with a technique known as"entanglement purification" to further developquantum communication over long distances. (J-.W Pan et. al. ,Nature, 421 721, 2003). Laser takes up gene therapyScientists in Germany have used a Ti:sapphirelaser to transfer DNA into a cell. Femtosecondlasers improve the transfer of DNA into cells andcould advance the fields of gene therapy and DNAvaccination, according to Uday Tirlapur andKarsten König of Friedrich Schiller University inJena. (U. Tirlapur and K. König, Nature, 418 290)

Power from terahertz beamsTerahertz beams are required in many scientificand technological applications, ranging from theimaging of biological materials to manipulatingquantum states in semiconductors. However,existing tera hertz sources have only been ableto generate low-power beams. Now, GwynWilliams and colleagues at the Brookhaven andLawrence Berkeley National Laboratories in the UShave created a beam that is several orders ofmagnitude more powerful than any other existingsource. (GL Carr et al., 2002 Nature, 420 153)

Crystals for Nonlinear OpticsThe significance and relevance of nonlinear optics(NLO) as an integral part of photonics is evidentfrom the fact that nearly all the photonic devicesmake use of various NLO materials in one-way orthe other. In the current research, we focus ondeveloping a variety of organic, inorganic andsemi-organic bulk single crystals.

From the Editor's DeskYet another volume of the Photonics News is inyour hands. It is with great pride and pleasurethat we bring out the 2003 edition of thisnewsletter. The third year of the twenty-first century hasbeen a fruitful year for ISP. Within a short periodof eight months the ISP websitewww.photonics.cusat.edu has won the GoldenWeb Award for the year 2003- 2004. The awardinstituted by the International Society of WebMasters and Web Designers will be a boost toISP and the site has become 'the site that onecannot afford to be left unvisited'. Some of theinstitutes advise their students to browse ISPwebsite as the first step to take up research inthe field of Photonics. The full credit of thisremarkable achievement goes to Mr. B.Aneeshkumar who is doing his research workhere and jointly at the Technical University ofEindhoven, The Netherlands, under the ISP-MHOprogramme of the Indo- Dutch collaboration ofCUSAT.

Work in the field of Lasers and Optoelectronicsat CUSAT has been recognized by the UGC byselecting it as a Potential Centre of Excellence inthe field of Lasers and Optoelectronics Sciences.This ambitious five-year scheme is undertakenjointly by the Departments of Physics, Electronicsand ISP through a newly established 'Centre ofExcellence in the field of Lasers andOptoelectronics Sciences' (CELOS), under thedirectorship of Prof. C.P. Girijavallabhan. One ofthe important programmes under this scheme isthe starting of a five year integrated M.Sc coursein Photonics. Students after their +2 leveleducation are admitted to this course. The firstbatch of students has already been admitted.We take this opportunity to welcome theseyoung members of the Photonics Family. Yet another feather in the cap of CUSAT is thatwe are going to host the Seventh InternationalConference "Photonics -2004 ", in which aboutsix hundred delegates are expected to take partduring December 8-11, 2004. ISP itself hassailed past a landmark by occupying its ownbuilding, beautifully designed which as one ofthe colleagues remarked, as 'owners' pride andneighbours envy'.

We recollect that Time has black-bordered oneof its section by the astronaut Dr. KalpanaChawla along with six of her colleagues gettingdissolved into infinity. Let us remember them asa courageous few who left the earth to fathomthe unfathomed cosmos.

V. P. N. Nampoori

Raman's bust installed in ISP

A new chapter was added to the history ofInternational School of Photonics on 9thSeptember 2002 by the unveiling of the bust ofSir C. V. Raman, the Father figure of Photonics inIndia, in the new ISP building. The HonourableVice Chancellor of CUSAT, Prof. N. Unnikrishnan Nair formally unveiled thebust in an official function that was held in the

Two different crystalgrowth systems, viz., hightemperature solutiongrowth (flux growth) androom temperaturesolution growth havebeen designed andfabricated for thispurpose. Preliminaryattempts are being madeto develop good qualityinorganic single crystalsof strontium tetraborateand bismuth triborate bythe flux growth technique.Semi organic crystalsgrown from aqueoussolution, such as the

recently discovered L-arginine tetraflouroborate,L-histidine tetraflouroborate, etc., with improvednonlinearity, SHG efficiency and mechanicalstability are also subjects of our investigation. Nonlinear Optics with NanoparticlesRecently we have investigated nonlinearabsorption in a silver nanosol and observed thatthey exhibit induced as well as saturableabsorption at the same wavelength, nearplasmon band, entirely depending on theexcitation fluence. Such a behavior is absent inorganic systems. Now we are planning to extendthe investigation to composite structures ofnanoparticles. organic materials. Such materials,usually called hybrid materials, have potentialapplications in the design and fabrication ofnanodevices, which can revolutionize photonictechnology.. Photothermal Studies Currently we have focused our work on theinvestigation of nanometal dispersed porousceramics. The open cell photo acoustic techniquehas been employed for the evaluation of thermaldiffusivity of liquid crystals. The photothermaldeflection studies on compound semiconductorshas been done by varying the degree of dopants.Investigations carried out on layered structuresrevealed very interesting properties in thepropagation of phonons during their transitthrough the specimen. We have been continuing the thermal lensstudies of fluorescent materials and recentlyinvestigated the effect of silver sol on theFluorescence Quantum Yield (FQY) of certainxanthene dyes. It has been observed that thepresence of silver sol decreases the FQY. This isexpected to have an important consequence inenhancing Raman scattering signals, which areoften obscured by fluorescence. Laser Generated Colliding PlasmaStudy of laser producedplasma is an importantprogramme of ISP.Recently plasma grouphas fabricated amultipurpose plasmachamber to investigatecolliding plasma underlaser irradiation. Studieson dusty plasma andplasma instabilities arealso being undertaken.

central hall of the building. The Registrar Dr. K.V.Kunhikrishnan and Prof. K.G. Nair, Director,Sophisticated Testing and Instrumentation Centre(STIC), offered felicitations. The installation ofthe statue was symbolic of the establishment ofthe science of Photonics as an integral part of theacademic culture of the University.

Near the newly unveiled bust of Sir. C. V. Raman:(From L to R) Prof. C. P. Girijavallabhan, Prof. V.P. N. Nampoori, Prof. N. Unnikrishnannair (V. C.-CUSAT), Prof. K.G.Nair, Dr. K. V. Kunhikrishnan

(Registrar), Prof. V. M. Nandakumaran, Mr.Sebastian Ouseph (F. O) and Prof. P.

Radhakrishnan

The bust, which now adorns the atrium of theSchool, is a facsimile of Prof. Raman, capturingthe minutest details of his countenance andappearance. The sculptor, Mr. Sasi whosepainstaking labour has created a statue thatenthralls all who visit the School, will always bementioned with appreciation and admiration inthe annals of ISP history.

CELOS- Recognition where it is due In view of the outstanding work carried out byteachers and researchers in laser related subjectsat CUSAT, the University Grants Commission,India identified Cochin University of Science andTechnology as a "University with Potential forExcellence in Lasers and OptoelectronicSciences" in March 2002. This unique scheme isintended to create centres of internationalexcellence in selected areas in a few Universitiesin India so that these rise as a "National Facility"where scientists and researchers from otherteaching/research institutions of the country canmake visits to conduct research in the relevantfield. Cochin University of Science and Technologywill receive a substantial financial assistance tothe tune of Rs. 30 crores for a period of 5 yearsas per this programme. This has led to theestablishment of a separate and independent"Centre of Excellence in Lasers & OptoelectronicSciences" (CELOS) in July 2002 with Prof. C. P.Girijavallabhan as its Director and with ISP andthe Departments of Electronics and Physics as theparticipating departments. As part of its human resource development in thefield of Photonics, CELOS has started anIntegrated M.Sc Course in Photonics during thecurrent academic year. This programme isintended for students who seek an understandingof the current approaches and emergingdirections in Photonics. In the near future the

Fibre Optics Technology1. Long Period Fibre Grating:Recent research work in the area of fibre optictechnology is centered on the fabrication of longperiod fibre gratings and employing them fordifferent sensor applications. The gratings havebeen fabricated in conventionaltelecommunication fibres, photosensitive fibresand plastic clad silica fibres by the point-by-pointmethod using the third harmonic radiation (355nm) from an Nd:YAG laser . Characterization ofthese long period gratings was carried out usingan optical spectrum analyzer. These gratings wereemployed for chemical sensing with large dynamicrange. Sensors developed using gratings wereshown to detect the presence of iron, nitrite etc.contained in water up to the ppb level. 2. Interferometric Sensors:Another landmark in sensor research was thedevelopment of interferometric sensor tomeasure force. A very compact and inexpensivesensor was designed and developed for thesimultaneous measurement of nitrites andchromium dissolved in water. A notable additionis the development of a sensor for ammoniadetection using an indicator dye deposited on anuncladded fibre acting as the sensing element. 3. Polymer Based Fibre OpticsThe global proliferation of optical fibre-basedcommunication networks has been the enablingfactor in the shift from the Electronics Age to theInformation (i.e. Photonics) age.

Though earlier silica glass fibres were extensivelyused, plastic optical fibres (POFs) are of greatcommercial interest now because they canmaintain flexibility at thicker fibre sizes makingthem easier to handle and install incommunication systems. Research group of thefibre lab in ISP designed and developed a

centre will also admit students to the Ph.Dprogramme in Photonics and related fields.

Conference NewsPhotonics: An Introduction-A Workshop forB.Tech. students International School of Photonics organized athree-day Workshop for B. Tech. students during14-16 February 2003. The Workshop was aimedat introducing the fast developing field ofPhotonics to the engineering students. Experts inthe field gave tutorials on the fundamentals ofthe subject as well as introductory lectures onPhotonics related research and development. Thelab demonstrations conducted as a part of theWorkshop exposed the young engineers to thevarious realms of the ongoing research in thisfield. Annual Photonics Workshop (APW 2003) Celebrating the occasion of the National ScienceDay as well as the anniversary of its owninception, International School of Photonics isorganizing the Annual Workshop on Photonics thisyear also during 27-28 February 2003. Theprimary objective of APW-2003 is to offer anintroduction to the various aspects of light-matterinteractions. The target group will be youngresearchers and teachers planning to enter thisnovel and fascinating field of research. For moredetails regarding the workshop contact:Prof. P. Radhakrishnan, Mr. C.M. Basheer,Coordinators, APW 03, International School ofPhotonics, Cochin University of Science &Technology, Cochin 682022. Email: radhak@cusat.ac.in

PHOTONIANS - The Alumni Association ofISP

International School of Photonics has beeninstrumental in bringing out around a hundredpostgraduates (M.Tech -OE&LT) and twenty Ph.D.holders in the area of Photonics within a shortperiod of eight years. It was deemed importantthat an academic centre of this stature launch itsown Alumni Association with the primary objectiveto keep connected all those who have been partof the Photonics family at CUSAT. The aim of theAssociation is to enhance interaction between ISPand the former students who are now in variousfrontier areas of Photonics research anddevelopment in both academic and industriallevels. The Association is expected to play a greatrole in the development of the group in the yearsto come joining hands with CELOS. Prof. V.P.N. Nampoori put forward the idea of anAlumni Association. The Alumni Association'Photonians' was formally inaugurated at ameeting held on 13th January 2003 at ISP byProf. C. P. Girijavallabhan, Director, CELOS andFounder Director, ISP. The meeting attended bythe staff, students and most importantly, manyformer students of ISP, elected the office bearersof the association. They include:

The Patron - Prof. V. M. Nandakumaran,

Director, ISP

drawing system to fabricate polymer optical fibresusing Polystyrene (PS) andPolymethylmetacrylate (PMMA). This group isconcentrating on the fabrication of some opticalcomponents like couplers apart from dye-dopedfibres

Laser ChaosThe work currently being pursued analyses theapplicability of long wavelength semiconductorlasers for optical communication especially in thesecure communication using chaotic opticalsystems. Chaotic outputs of direct currentmodulated semiconductor lasers are used forencoding the message by direct amplitudemodulation at the output of the transmitter.

The encoding was done successfully in analogand digital messages. The encryption techniqueinvolves the achievement of perfectsynchronization between the transmitting andreceiving systems as well as a proper masking ofthe signal in the intermediate stages. Aproportional - integral feedback function issuccessfully used for this purpose and the resultsare very encouraging. The level of securityoffered by this scheme and the effect of a timedelay in the synchronization of the receiver withthe transmitter is being investigated. Computational Neuro scienceThe momentum gained in the research of fiber The study of the coordination of the brain regionsin normal and epileptic subjects brought forthsome interesting results that are expected to beof use to clinicians as well. The establishment ofsynchronous activity in regions that are far apartduring the transient period of an epileptic attackwas detected by this method. The complexity ofthe signals under various conditions involving restand physical fatigue as well as cognitive andmental task conditions was also carried out. Theinvestigation showed that there exists adifference in the complexity of the EEG signals forwomen as compared to men. Efforts are also onto devise EEG based brain maps as well asdevelop these into an online tool for use indiagnosis and treatment of neurologicaldisorders. In addition, the group could establishresearch collaborations with the Amrita Instituteof Medical Sciences, Cochin and the Departmentof Human Biology, University of Cape Town,South Africa.

In the limelight

Mrs. Achamma Kurian was awarded Ph.D.

under the Faculty of Technology, CUSAT,for her thesis entitled "Characterization ofPhotonic Materials using Thermal LensTechnique." She is currently a SeniorLecturer at the Catholicate College,Pathanamthittta.

International School of Photonics is to host

PHOTONICS 2004, a biennially heldInternational Conference onOptoelectronics, Fibre optics andPhotonics. The conference is sponsored bySPIE, The International Society for OpticalEngineering. The conference is a forum forinteraction and exchange of ideas among

The President- Mr. Jibukumar

The Vice President- Dr. Achamma Kurian

Secretary & Treasurer-Prof.

P.Radhakrishnan

Joint Secretaries- Dr. Riju C. Issac (outside

India) & Mr. Fazludeen (within India)

Staff Advisor- Prof. V. P. N Nampoori

Executive members- Ms. Bindu Krishnan,

Mr. Deepak M. K., Mr. JameskuttyThomas, Ms. Priyamvada M.C, Mr.Yedukondalu. K and Mr. Satheesh.

The Association has launched a web site,http://www.photonics.cusat.edu/alumni.html andan electronic newsletter, which is maintained byMr. B. Aneeshkumar. These are expected to actas communication links among the 'Photonians'.An editorial board has also been formed for thisnewsletter "VIBGYOR", which includes Prof. V P NNampoori, Dr. Reji Philip, Dr. Deepthy A, Ms.Rekha Mathew, Mr. Manu Punnen John and Mr.Jijo P.U. The Association is well into action byorganizing a seminar jointly with the PhotonicsSociety of India by Prof. V P N Nampoori in honourof Late Dr. Kalpana Chawla on 13th of February2003.

Alumni Column Carbon Nanotubes - Material of the decade

Sudhir C , Laborotairé POMA, Université d'Angers, France

Email: sudhirnam@yahoo.com

It is there in everything living and dead. It can bein what you drink and what you wear. It can besoft, it can be hard! It can be ugly and the mostbeautiful! It is Carbon. It is a special elementthat has fascinated chemists. Carbon can takevarious forms like soft and slippery graphite tothe hardest natural substance ever discovered,diamond. Carbon can be in the form of a football,fullerene, or it can be in the form of tubes,nanotubes! Meet the latest (although fullerenestructures were discovered after) incarnation ofcarbon, Nanotubes ! Sumio Iijima and coworkersat the NEC labs reported the discovery of carbonnanotubes, in 1991, while the first carbonfilaments of nanometer dimensions wereprepared by Morinobu Endo in France. Carbon nanotubes are hexagonal networks ofcarbon atoms that is rolled up in the form of aseamless cylinder. These structures haveexceptional electronic and mechanical properties.High-resolution transmission electron microscope(TEM) and scanning electron microscope (SEM)photographs of carbon nanotubes have confirmedthat carbon nanotubes are cylindrical structureswith hexagonal lattice. Three possible structuresnamely armchair, zigzag and chiral aredifferentiated depending upon the rolling ofgraphene layer. A vector called Chiral vectordetermines the type of the nanotube. In a twodimensional hexagonal lattice, a chiral vector maybe defined as Ck = na1 + ma2 where a1 and a2

are unit vectors in the two dimensional hexagonallattice. The angle between the chiral vector and a1

participants from research institutions,universities, government organizationsand industry. For more information visitthe conference home page

Seminar by Visitors 1. Prof. R. PratapProf. Emeritus, ISPEvolution of Thought Function 8th February, 2002.2. Dr. V. KumarScientist, Centre for Materials for ElectronicTechnology, Thrissur.Synthesis of Nanocrystalline Materials15th April 20023. Dr. G. D. SockalingamUniversity of Reims, FranceBiomedical Applications of VibrationalSpectroscopy.12th November 20024. Dr. C. Murali KrishnaCentre for Laser Spectroscopy, MAHE, ManipalLaser Spectroscopy for diagnosis and earlydetection of malignancy12th November 20025. Prof. Dino JaroszynskiUniversity of StrathclydeIntense Laser Interaction with Plasma13th December 2002.

Accolade 1. Prof. V P N Nampoori attended the BelgiumPhotonics Fabrication Europe Conference heldduring 28th October-1st November 2002 atBrugge. He presented papers on fibre opticsensors by Thomas Lee S and P Suresh Kumar atthe Transducing Materials and Devicesconference.2. Dr. A. Deepthy, DST Young Scientist Fellow atISP, won the best thesis award at the NationalLaser Symposium2002, held atThiruvananthapuram. Her thesis entitled "Growthand Physical Properties of Nonlinear Optical KTPand Ferroelectric GPI single crystals" was doneunder the supervision of Prof. H.L. Bhat at theIndian Institute of Science, Bangalore.

3. Research Scholars of ISP, Thomas Lee S andSajan D. George presented papers at thePhotonics Asia-02 along with P. Suresh Kumarand K. Geetha at the APOC-2002 held atShanghai, China in October 2002.

is often termed as the chiral angle.

As the graphene sheets (single sheets ofgraphite) are rolled into tubes or cylinders, thesechiral vectors meet. Thus chiral vectors formcircumferences of the nanotubes in the cylindricalcross section. The values of the integers n and mdetermine the type of the nanotube. An n =mvalue is that of the armchair type, while if eitherof n or m equals zero with the chiral angle 0, it iszigzag. All other types are classified under chiralnanotubes. The properties of the nanotubes aredetermined by their diameter and the chiralangle. Nanotubes of carbon are prepared by laservaporization of a carbon target in a furnace at1200°C. Cobalt, nickel or iron catalyst preventsthe ends from being "capped" during synthesis,thus allowing the tubes to grow. Pyrolysis andmicrowave plasma CVD are also common. Thedetailed mechanism of the growth of nanotubes isyet to be completely understood. Carbon nanotubes have unique electronic andmechanical properties. The electrons in thenanotubes are well quantum confined, normal tothe tube axis (the idea of quantum wires!). Thusthey can propagate along the nanotube axis andtheir wave vector will be in the axial direction.Carbon nanotubes can be in the form of semiconductors or metals depending upon thedirection in which the nanotubes are rolled. This isbecause the electronic structure of graphene isdependent on the boundary conditions. Themetallic nature depends on their diameter andchirality. The singularities that correspond to thesub bands differentiate them from conventionalmetals. Another interesting property of steelcarbon nanotubes is the exceptionally highmechanical strength with a Young's modulus of 1

TPa (1012 N/m2). This is as much as five timesthat of steel! Unlike carbon fibers, they form kinklike ridges that can reform under the release ofthe stress.

Recent publications from ISP 1. Thermal lens spectrum of organic dyes usingoptical parametric oscillator.Achamma Kurian, K. P. Unnikrishnan, Sajan D.George, Pramod Gopinath, V.P.N Nampoori & C.P. G. Vallabhan. Spectrochimica Acta part A, 59 ,487-491, 2003. 2. Studies on two-photon absorption of anilineusing thermal lens effect. Achamma Kurian, K P Unnikrishnan, S ThomasLee, Sajan D. George, V P N Nampoori and C P GVallabhan.J. of Nonlinear Optical Physics & Materials.

3. Effect of pH on quantum yield of fluoresceinusing thermal lens technique. Achamma Kurian, Nibu A George, Sajan D George,K P Unnikrishnan, Binoy Paul, Pramod Gopinath,V P N Nampoori and C P G Vallabhan,Journal of Optics, 31 (1), 29-36, 2002.

4. Studies on fluorescence efficiency andphotodegeneration of rhodamine 6G doped PMMAusing thermal lens technique. Achamma Kurian, Nibu A George, Binoy Paul, V PN Nampoori and C P G Vallabhan.Laser Chemistry, 20 (2-4), 99-110, 2002.

5. Realization of optical logic gates using thermallens technique.Achamma Kurian, Nibu A George, S. Thomas Lee,K P Unnikrishnan, V P N Nampoori and C P GVallabhan.Laser Chemistry, 20 (2-4), 81-87, 2002.

6. Photoacoustic measurement of transportproperties in doped GaAs epitaxial layers.Sajan D George, Dilna. S, P. Radhakrishnan, C. P.G. Vallabhan and V.P.N.Nampoori.Physica Status Solidi (A), 195 No-2, 416-421,2003.

7. Effect of Te doping on thermal diffusivity ofBi2Se3 crystals: A study using open cellphotoacoustic technique. Sajan. D. George, Saji Augustine, Elizabeth

These special electronic and mechanicalproperties of carbon nanotubes make them highlypotential and promising candidates formultifarious applications. The excellentmechanical properties can be exploited forreinforcement applications, lightweight bulletproofvests and nanotube tips for scanning probes. The field emission properties in nanotubes haveled to the development of nanoscale electronictransistors. The idea of a nanotube field emitterwas first proposed by deHeer et. al. In a recentpaper, Ali Javey and colleagues have claimed tohave fabricated and studied carbon nanotubesintegrated with a gate of high dielectric constant,thus enhancing the performance. Recently,Zhifeng Ren and co workers of Boston College,Massachusetts demonstrated that large areaperiodic arrays of well-aligned carbon nanotubescould be fabricated on Ni dots using a self-assembly lithographic technology. A 'crystal forest'was created by laying down periodic nanodots ofNickel by depositing the metal in the interstices ofa two dimensional colloidal crystal. The defects inthe waveguides act as optical waveguides. Avacant row of posts will create a channelpermeable to the otherwise forbiddenwavelengths. If realized this would pave way tomolecular optoelectronics.

Owing to such exceptional features, Carbonnanotubes are the most researchednanostructures. The quantum nature ofnanotubes and their electronic structures will beexplored in the coming years. We can expect thedevelopment of new electronic elements based oncarbon nanotubes. But what next? Science will findits way out.

We hear that .....

Spotting of excited moleculesMarcus Dyba and Stephen Hall of Max PlanckInstitute Germany spotted excited molecules of33nm width using the focused light of 760 nmradiation and conventional optics along the opticaxis. This was accomplished by exciting themolecules with a femto second pulse andsubsequent depletion of their excited state withred shifted pico second pulsed counterpropagating coherent radiation. The sub diffractedl/23 spot enabled for the first time to image themembrane of bacillus megateruim using far fieldfluorescence microscopy. The technique could be

Mathai, P. Radhakrishnan,V. P. N. Nampoori andC. P. G. Vallabhan.Physica Status Solidi (A), In press.

8. A photoacoustic study of the effect of dopingconcentration in the transport properties of GaAsepitaxial layers.Sajan D George, Dilna. S, Prasanth. R, P.Radhakrishnan, C. P. G. Vallabhan and V. P. N.Nampoori.Optical Engineering ,42(5), 2003.

9. Photoacoustic Investigation of doped InP usingopen cell configuration.Sajan . George, C.P.G.Vallabhan, M. Heck,P.Radhakrishnan and V.P.N.Nampoori.Nondestructive Evaluation and Testing,18, 75-82,2002.

10. Design and development of an LED basedfiber optic evanescent wave sensor forsimultaneous detection of chromium and nitritetraces in water. P. Suresh Kumar, S. Thomas Lee,C.P.G.Vallabhan, V.P.N. Nampoori and P.Radhakrishnan.Optics Communications, 214, 25-30, 2002.

11. A Fiber optic evanescent wave sensor used forthe detection of trace nitrites in water.P Sureshkumar, C P G Vallabhan, V P NNampoori, V N Sivasankara Pillai and PRadhakrishnan.J. of Optics A-Pure & Appl. Opt., 4, 247-250,2002.

12. Compact polarization-independent Mach-Zhender space switch combining carrier depletionand the quantum confined stark effect. R.Prasanth, J.E.M.Haverkort, J.H.Wolter.IEEE J. of Quantum Electronics Vol: 39 , 2003,379- 383.

13. Photothermal deflection studies on GaAsepitaxial layers.George N A, Vallabhan C P G, Nampoori V P N andRadhakrishnan P.Applied Optics, 41(24), 5179-5184, 2002.

14. Degenerate four wave mixing in some metalphthalocyanines and naphthalocyanines. K. P. Unnikrishnan, Jayan Thomas, V. P. N.Nampoori and C. P. G. Vallabhan, Chem. Phys., 279, 209-213, 2002.

15. Third order nonlinear optical studies ineuropium naphthalocyanine using degeneratefour wave mixing and Z-scan. K. P. Unnikrishnan, Jayan Thomas, V. P. N.Nampoori and C. P. G. Vallabhan, Optics Communications, 204, 385-390, 2002.

16. Wavelength dependence of nonlinearabsorption in a bis-phthalocyanines studied usingZ-scan technique. K P Unnikrishnan, Jayan Thomas, V P N Nampooriand C P G Vallabhan.Applied Physics B, 75, 871 , 2002.

17. Nonlinear absorption in certain metalphthalocyanines at resonant and near resonantwavelengths.K P Unnikrishnan, Jayan Thomas, V P N Nampooriand C P G Vallabhan

useful in micro lithography and optical datastorage.(PRL 88, 163901, 2002) Laser leads nerve growth

Researchers haveshown that a laserbeam can guidenerve cells to growin a particulardirection. Thistechnique must

help damaged nerves to re-grow or could convertthem to electronic implants such as artificialretinas and prosthetic limbs. Nerve cells growingover a glass plate take the path pointed out by ared laser, reports Allen Ehrlicher of UniversityLeipzing in Germany. The nerves move towardsthe spot of laser light traveling as if drawn by agentle slope. The laser does not harm the cellseven if they are forced to take sharp turns.(Nature, Science update, December 2002.) Adaptive optics gives a hand to opticiansDonald Miller and Larry Thibos of IndianaUniversity have used a technique normally usedin astronomy to see living cells in the humanretina for the first time. They believe thatinstruments that use "adaptive optics" could helpin the early diagnosis of retinal diseases. Theycreated an "ocular aberrometer" to measure thedeviation in optical wavefronts reflected by theretina and also developed technology thatcorrects these deviations. Combined with a retinacamera, the researchers will be able to makehigh-resolution, non-invasive observations of cellsat the back of the eye.(Physics Web, January 2003) Laser-DentistDentists could soon swaptheir drills for painlesstools based on pulsedinfrared lasers. AndreiRode of the AustralianNational University and hiscolleagues have shownthat ultrashort pulses ofradiation

Optics Communication (In press)

18. Microbent Optical Fibers as Evanescent WaveSensors . S Thomas Lee, K. Geetha, V P N Nampoori, C P GVallabhan and P Radhakrishnan Optical Engg., 41, 3260-3264, 2002.

19. A microbent fiber optic pH sensor.S. Thomas Lee, B. Aneeshkumar, P.Radhakrishnan, C. P. G. Vallabhan and V. P. N. NampooriOptics Communications, 205, 253 - 256 , 2002.

20. Photoacoustic studies on n-type InP.Nibu A. George, C. P. G. Vallabhan, V. P. N.Nampoori, and P. Radhakrishnan, Optical Engineering, 41(1), 251-254, ,2002. 21. Optical properties of porphyrins in borateglassy matrix.Kumar, G. A.; Thomas, Vinoy; Jose, Gin;Unnikrishnan, N. V.; Nampoori, V. P. N.,Materials Chemistry and Physics , 73(2-3), 206-211, 2002.

22. Chaotic encryption using long wavelengthdirectly modulated semiconductor lasers.V. Bindu, V M Nandakumaran.J. Optics A- Pure & Appl. Optics, 4 , 115, 2002.

23. Coordination in the Dynamics of the Brain asInferred from EEG Analysis.Pravitha Ramanand and V.P.N. NampooriIntl. Journal of Neuroscience, 112, 10, 1245 -1262, 2002.

And the last word...When you know a thing, to hold that you know it; and

when you do not know a thing, to allow that you donot know it; this is knowledge

-Confucius

The only thing I know is that I do not know anything-Socrates

Editor: Dr. V P N Nampoori Creative Team: Rekha Mathew, PravithaRamanandOnline version: B.Aneesh

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