35th meeting of the section atomic molecular and optical ... · this meeting is organized under the...

35th Meeting of the sectionAtomic Molecular and Optical Physics (AMO)

Program and abstracts

CongresHotel De WereltLunteren

October 11 and 12 2011

Scientific Commitee:

Giel Berden • Martin van Exter • Ronald Hanson

Ronnie Hoekstra • Gert 't Hooft • Femius Koenderink

Servaas Kokkelmans • Leo Meerts (chair) • Herman Offerhaus

Robert Spreeuw • Peter van der Straten • Wim Vassen • Caspar van der Wal

This meeting is organized under the auspices of the NNV-section Atomic, Molecular and Optical Physics,

with financial support of the Dutch Science Foundation and the Foundation FOM.

Conference coordination:

Erna Gouwens (RU)

2

Tuesday 11 October 2011

10.00 Arrival, registration

10.40 Opening by the chair man of the section AMO Leo Meerts

chair Dries van Oosten

10.45 I1 Martin Weitz (Quantum Optics Group, University of Bonn, Germany)

“Bose-Einstein condensation of light”

11.30 Short lectures: (Europa room)

O1 W. Lewoczko-Adamczyk (Van der Waals – Zeeman Institute,

University of Amsterdam)

“Bose-Einstein condensation in microgravity”

O2 S.B. Koller (University of Utrecht)

“Spin drag in a Bose gas”

O3 R. Gerritsma ( Quantum Optics and Spectroscopy, University Innsbruck,

Austria)

“Digital quantum simulation with trapped ions.”

O4 E.J. Salumbides (Laser Centre VU University Amsterdam)

“Test of QED in the ground electronic rotational sequence of the hydrogen

molecule”

12.30 Lunch

chair Martin van Exter

14.00 I2 Allard Mosk (Institute for Nanotechnologie, University of Twente)

Scattering lens resolves nanostructure

14.45 Short lectures: (Europa room)

O5 S.R. Huisman (Institute for Nanotechnologie, University of Twente)

“Near-field investigation of localized modes in slow-light photonic crystal

waveguides”

O6 Martin Frimmer (FOM Institute AMOLF)

“Signature of electromagnetically induced transparency in a plasmonic

molecule’s local density of optical states”

O7 T. Denis (Laser Physics and Nonlinear Optics, University of Twente)

“Mapping electromagnetic fields inside photonic crystals”

O8 Frerik van Beijnum (Leiden University)

“Speckle correlation functions in plasmonics“

erna

Sticky Note

haakje openen haakje sluiten bij de titel

3

Tuesday 11 October 2011

15.45 Coffee/tea break

16.15 Short lectures: (Europa room

O9 Thijs Meijer (Eindhoven University of Technology)

“Using atom lithography to create magnetic nanostructures.”

O10 Jelmer J. Renema (Leiden University)

“Full characterization of NbN Nanodetectors”

chair Giel Berden

16.45 Poster Introduction – 1 minute per poster

18.00 Dinner (restaurant) (attach posters)

19.15 Poster presentations (Europa room, please remove posters after

the evening lecture )

21.15 Evening lecture chair Leo Meerts

Rob van Dorland (Royal Netherlands Meteorological Institute)

“The human factor in Climate Change”

POSTERS AND ORAL PRESENTATIONS

For oral contributions we have a limited time of 12 minutes per presentation (+3 minutes for discussion).

The posters can be placed before or during the dinner.

Befor 24.00 hr all posters must be removed.(The room will be cleaned)

4

Wednesday 12 October 2011

08.00 Breakfast (restaurant, please remove the luggage from your room)

chair Giel Berden

08.45 I3 Thomas R. Rizzo (Ecole Polytechnique Fédérale de Lausanne (EPFL),

Switzerland)

“Spectroscopy of biological molecules in cold ion traps: examples, challenges

and perspectives”

09.30 Short talks (Europa room)

O11 Sander Jaeqx (FOM Insitute Rijnhuizen)

“The Far-Infrared region as probe for the secondary structure of peptides”

O12 Erik Garbacik (Optical Sciences Group, University of Twente)

“Background-free nonlinear microspectroscopy with vibrational molecular

interferometry”

O13 Frans R. Spiering (Molecular and Biophysics, IMM Radboud University

Nijmegen)

“Absorption by molecular oxygen in the atmospheric bands”

O14 Vivike Lapoutre (FOM Institute Rijnhuizen)

“Probing the adsorption of carbon monoxide on transition metal clusters using

IR photodissociation spectroscopy”

10.30 Coffee/tea break

chair Wim Vassen

11.00 I4 Robert J. Spreeuw (Van der Waals – Zeeman Institute, University of

Amsterdam)

“Lattices of atom microtraps on magnetic-film atom chips”


O15 C.K. Bishwakarma (Molecular and Laserphysics, IMM Radboud University

Nijmegen)

“Differential cross section measurement for Inelastic scattering of CO

with Ar/He”

5

Wednesday 12 October 2011

O16 Rienk T. Jongma (Molecular and Biophysics, IMM Radboud University

Nijmegen)

“FELIX user facility Nijmegen: advanced MIR/FIR sources”

O17 Paul Jansen (Laser Centre VU University Amsterdam)

“Intergalactic alcohol for detecting drifting constants”

O18 Wouter Engelen (Eindhoven University of Technology)

“Ultrashort electron bunches from an ultracold electron source”

12.45 Lunch

chair Peter van der Straten

13.55 Presentation winner poster award


O19 Hannes Bernien (Kavli Institute of Nanoscience, Delft University)

“High-fidelity projective readout of a solid-state quantum register”

O20 O. Gonzalez-Magaña (KVI University of Groningen)

“The effect of peptide length on VUV photofragmentation”

14.40 I5 Chris Monroe (Joint Quantum Institute and University of Maryland USA)

“Quantum networks of trapped ions”

15.20 Finish

6

Poster ProgramP1 Real-time breath analysis by Optical Parametric Oscillator based Off-Axis integrated cavity

output spectroscopyDenis D. Arslanov • Molecular and Laser Physics, IMM Radboud University Nijmegen

P2 Novel searches for cosmological variation of the proton-to-electron mass ratio from high-redshift H2 absorbers in quasar spectra.Julija Bagdonaite • VU University Amsterdam

P3 IR Structural Characterization of Transition Metal Carbene Cations: Ta, W, Ir, PtJoost Bakker • FOM Rijnhuizen

P4 Background-free and Doppler-reduced direct frequency comb spectroscopy of Rubidium atoms using coherent control.I. Barmes • VU University Amsterdam

P5 Large-Area Pulsed Laser Deposition of thin films with atomic precisionH.M.J. Bastiaens • Mesa+ Institute for Nanotechnology, University of Twente

P6 Up-scaling high-harmonic generation in a capillaryH.M.J. Bastiaens • Mesa+ Institute for Nanotechnology, University of Twente

P7 Reflectance Tuning at Extreme Ultraviolet (EUV) Wavelengths with Active Multilayer MirrorsMuharrem Bayraktar • Mesa+ Institute for Nanotechnology, University of Twente

P8 Deceleration and trapping of heavy diatomic molecules for precision measurementsJ.E. van den Berg • KVI Atomic Physics, University of Groningen

P9 Rydberg CrystalsR.M.W. van Bijnen • Eindhoven University of Technology

P10 Velocity map Imaging study of the photodissociation of X–O2 (X = Xe, C2H4 and C6H6): O(1D) detectionBin Yan • Molecular and Laser Physics, IMM Radboud University Nijmegen

P11 Electron transfer in collisions of highly charged ions with Na(3s) and Na*(3p)I. Blank • KVI, Atomic Physics, University of Groningen

P12 Spin drag in a Bose GasP.C. Bons • Nanophotonics University of Utrecht

P13 Two- and three-body loss of spin-polarized metastable helium atoms in an optical dipole trapJ.S. Borbely • VU University Amsterdam

P14 Ethylene detection quantum cascade laser based OFF-AXIS integrated cavity output spectroscopy Raymund Centeno • Molecular and Laser Physics, IMM Radboud University Nijmegen

P15 Coherent control in single-crystalline gold nanoantennasTing Lee Chen • Mesa+ Institute for Nanotechnology, University of Twente

P16 Optimization of the current extracted from an ultracold ion source (UCIS)N. Debernardi • Eindhoven University of Technology

P17 EF1Σg+ - X1Σg

+ two-photon precision studies in hot H2G.D. Dickenson • VU University Amsterdam

P18 Femtosecond pump-probe coincidence imaging in molecular photodynamics studies Mohammad Fanood • VU University Amsterdam

P19 Unraveling the electronic structure of monodehydrogenated PAH ions with FELIXHéctor Alvaro Galué • FOM Rijnhuizen

P20 Stability study of high-harmonic generation in a capillary for seeding of free-electron lasersS.J. Goh • Mesa+ Institute for Nanotechnology, University of Twente

P21 Pump-probe photofragmentation of a trapped isolated peptideO. Gonzalez-Magaña • KVI Atomic Physics, University of Groningen

7

Poster ProgramP22 First and second sound in a weakly interacting Bose gas

A. Groot • Nanophotonics University of UtrechtP23 Spectroscopic evidence for oxazolone structures in anionic b-type peptide fragments

Josipa Grzetic • FOM RijnhuizenP24 Laboratory study of Rayleigh-Brillouin scattering for measuring the winds of the Earth

Z. Gu • VU University AmsterdamP25 Sensitive fluorescence detection using a camera from the gaming industry

B.L. Van Hoozen • Mesa+ Institute for Nanotechnology, University of TwenteP26 Structure and magnetism of terbium clusters

Jeroen Jalink • Spectroscopy of Solids and Interfaces, IMM Radboud UniversityP27 Towards an ultracold mixture of metastable helium and rubidium

Steven Knoop • VU University AmsterdamP28 SuperGPS through optical networks’ for fundamental science and innovation

J.C.J. Koelemeij • VU University AmsterdamP29 Molecular hydrogen ions, the proton-electron mass ratio and the proton size

J.C.J. Koelemeij • VU University AmsterdamP30 Discovery of electron-hole Cooper pairs in a semiconductor

A.J. van Lange • Debye Institute for NanoMaterials Science, University of UtrechtP31 Compact/Low Power RF Technology for Time Resolved Electron Microscopy

A. Lassise • Eindhoven University of TechnologyP32 Photoelectron-photoion coincidence imaging of ultrafast control in multichannel molecular

dynamics.Carl Stefan Lehmann • VU University Amsterdam

P33 Lattices of atom microtraps on magnetic-film atom chipsV.Y.F. Leung • Van der Waals-Zeeman Instituut, University of Amsterdam

P34 Towards Bose-Einstein condensation in a 1D box on an atom chipW. Lewoczko-Adamczyk • Van der Waals-Zeeman Instituut, University of Amsterdam

P35 CO ice photodesorption; a wavelength-dependent studyHarold Linnartz • Sackler Laboratory for Astrophysics, Leiden Observatory

P36 A QCL-based sensor for exhaled NO analysisJulian Mandon • Molecular and Laser Physics, IMM Radboud University Nijmegen

P37 Nitric oxide detection based on Off-Axis integrated cavity output spectroscopyD. Marchenko • Molecular and Laser Physics, IMM Radboud University Nijmegen

P38 Absolute density-profile measurement of molecular beam by using multiphoton ionization of Xe.Congsen Meng • VU University Amsterdam

P39 Programmable pulse sequences for XUV frequency comb spectroscopy at kHz-level accuracyJ. Morgenweg • VU University Amsterdam

P40 Atom-light interactions in photonic nanostructuresB.O. Mussmann • Debye Institute for NanoMaterials Science,Utrecht University

P41 High precision UV measurements in CO, towards a laboratory test of the time-invariance of µAdrian J. de Nijs • VU University Amsterdam

P42 Coherent soft-X-ray microscopy using few-cycle laser pulsesDaniel Noom • VU University Amsterdam

P43 Atomic parity violation: Ra+

M.Nuñez Portela • KVI Atomic Physics, University of GroningenP44 Single-shot femtosecond electron diffraction

P.L.E.M. Pasmans • Eindhoven University of Technology

8

Poster ProgramP45 Towards ultra-stable frequency combs from NIR to XUV wavelengths

T.J. Pinkert • VU University AmsterdamP46 Velocity map imaging of a slow beam of ammonia molecules inside a linear quadrupole

Marina Quintero Pérez • VU University AmsterdamP47 Photoelectron spectroscopy of chiral molecules using pulse shaping and coincidence imaging

N. Bhargava Ram • VU University AmsterdamP48 Fragmentation dynamics of polycyclic aromatic hydrocarbons after keV ion irradiation

G. Reitsma • KVI Atomic Physics, University of GroningenP49 Numerical optimization of broadband CARS

A.C.W. van Rhijn • MESA+ research institute, University of TwenteP50 Nature’s energy source probed by IR spectroscopy: Can ATP act as a fuel in the gas phase?

Anouk M. Rijs • FOM RijnhuizenP51 Spectroscopy of the 1s2s 3S1 – 1s2s 1S0 transition in quantum degenerate helium

R. van Rooij • VU University AmsterdamP52 Extending the frequency coverage of multi-heterodyne spectroscopy

Axel Ruehl • VU University AmsterdamP53 State-to-state differential cross sections for inelastic scattering of ND3 with Ar and He

A.K. Saha • Molecular and Laser Physics, IMM Radboud University NijmegenP54 Real-time analysis of sulphur containing volatiles emitted from larvae-infested Brassica plants

using Proton Transfer Reaction Mass spectrometryDevasena Samudrala • Molecular and Laser Physics, IMM Radboud University Nijmegen

P55 Digital holographic imaging of latent fingerprintsR.J.T. Scheers • Mesa+ Institute for Nanotechnology, University of Twente

P56 Fourier Microscopy of single plasmonic and metamaterial nanoscatterersIvana Sersic • FOM Institute AMOLF

P57 Polarization-dependent ponderomotive gradient force in a standing waveP.W. Smorenburg • Eindhoven University of Technology

P58 Ionization and fragmentation of free oligonucleotides by kev ions and soft x-ray photonsM. Tiemens • KVI Atomic Physics, University of Groningen

P59 Design of a high quality radially polarized light at 405 nm using thin metal film circular grating.K. Ushakova • Delft University of Technology

P60 The electronic spectra of Bent carbon chains - ‘Particle-in-a-box’ behavior D. Zhao • VU University Amsterdam

P61 Quantum optics with semiconductor spin ensemblesA.R. Onur • KVI Atomic Physics, University of Groningen

9

I1 O1

Bose-Einstein condensation of light

Martin Weitz

Institut für Angewandte Physik,

Universität Bonn, Wegelerstr. 8, D-53115 Bonn

Bose-Einstein condensation, the macro-

scopic ground state accumulation of

particles with integer spin (bosons) at

low temperature and high density, has

been observed in several physical systems,

including cold atomic gases and solid

state physics quasiparticles. However,

the most omnipresent Bose gas, black-

body radiation (radiation in thermal

equilibrium with the cavity walls) does

not show this phase transition. The

photon number is not conserved when

the temperature of the photon gas is

varied (vanishing chemical potential),

and at low temperatures photons

disappear in the cavity walls instead of

occupying the cavity ground state. Here

I will describe an experiment observing a

Bose-Einstein condensation of photons

in a dye-filled optical microcavity. The

cavity mirrors provide both a confining

potential and a non-vanishing effective

photon mass, making the system formal-

ly equivalent to a two-dimensional gas

of trapped, massive bosons. By multiple

scattering of the dye molecules, the

photons thermalize to the temperature of

the dye solution. In my talk, I will begin

with a general introduction and give an

account of current work and future plans

of the Bonn photon gas experiment.

Bose-Einstein condensation in microgravity

W. Lewoczko-Adamczyk • for the

Quantus team

Institut für Physik,

Humboldt-Universität zu Berlin

Van der Waals-Zeeman Instituut,

Universiteit van Amsterdam

We report the preparation and observa-

tion of a Bose-Einstein condensate

during free fall in a 146-meter-tall

evacuated drop tower [1]. During the

expansion over 1 second, the atoms form

a giant coherent matter wave that is

delocalized on a millimeter scale, which

represents a promising source for matter-

wave interferometry to test the universal-

ity of free fall with quantum matter.

We will also present our compact and

portable BEC-apparatus. Special emphasis

will be put on its robustness, which

opens new routes for quantum optics

experiments also in other microgravity

platforms like sounding rockets or space

station.

This work was realized within the

QUANTUS collaboration and is support-

ed by the German Space Agency (DLR)

[1] T. van Zoest et al, Science 328, 1540-1543,

(2010)

Fig. 1 Cuts through the ZARM drop tower facility in

Bremen (A) and the capsule (B) containing the heart

of the BEC experiment (C). Published by AAAS.

10

O2

Spin Drag in a Bose Gas

S.B. Koller, A. Groot, P.C. Bons, R.A. Duine,

H.T.C. Stoof, P. v.d. Straten

Nanophotonics,

Debye institute, Utrecht

Spintronics, a field in solid state physics

where the focus lies on the current of

spin polarized electrons rather than

charge current, is heavily investigated.

An important effect in this field is spin

drag where a spin current of e.g. spin up

electrons drags electrons of spin down

through collisions. Experiments in this

field are limited to fermionic particles

and are often flawed by impurities and

phonons, which lead to ohmic resistance.

Here we present the results of an experi-

ment [1] where we measure spin drag in

an ultra cold atomic Bose gas for the first

time. We perform two different measure-

ments. In the first we exert a force on

one of two spin components and measu-

re the finite drift velocities between

them. In the second we first spatially

separate the two spin components and

then observe the damping of the mutual

oscillation in a trap. The results confirm

the theoretical predictions in the classical

and in quantum regime above the phase

transition to BEC, where this effect is

Bose enhanced [2].

[1] S.B. Koller, A. Groot, P.C. Bons, R.A. Duine,

H.T.C. Stoof, P. v.d Straten Spin drag in a

Bose Gas ArXive

[2] R.A. Duine, H.T.C. Stoof Spin Drag in

Noncondensed Bose Gases, PRL 103 170401

11

O3 O4

Digital quantum simulation with trapped ions

R. Gerritsma, B. Lanyon, C. Hempel, D. Nigg,

M. Müller, F. Zähringer, P. Schindler,

J.T. Barreiro, M. Rambach, G. Kirchmair,

M. Hennrich, P. Zoller, R. Blatt, C.F. Roos

Institut für Quantenoptik und

Quanteninformation, Otto-Hittmair-Platz 1,

A-6020 Innsbruck, Austria.

Simulating quantum physics on a classi-

cal computer becomes impractical for

large systems. A proposed solution [1]

would be to use a quantum simulator:

A well controlled quantum system that

mimics the system to be simulated [2].

Here, we report on the implementation

of digital quantum simulation using

trapped ions [3]. A digital quantum

simulator is a quantum device that can

be programmed to efficiently simulate

any other local system. We use up to

6 ions and up to 100 quantum gates to

reproduce the dynamics of a range of

spin models. We demonstrate the attrac-

tivity of the digital approach by simula-

ting interactions which are beyond those

naturally present in our simulator.

Quantitative bounds for the simulation

quality are obtained.

[1] S. Lloyd, Science 273, 1073 (1996)

[2] I. Buluta and F. Nori, Science 326,

108 (2009)

[3] B. Lanyon et al., Science Express,

1 September 2011

Test of QED in the ground electronicstate rotational sequence of the hydrogen molecule

E.J. Salumbides, G.D. Dickenson, T.I. Ivanov,

W. Ubachs

LaserLaB VU Amsterdam

We have pursued a systematic study of

quantum electrodynamic (QED) effects

in a progression of 16 rotational quan-

tum states in the X 1Σg+, v=0 ground

state of H2 [1]. Accurate calibrations of

the Q(J=6-16) transition energies were

carried out for the EF 1Σg+ - X 1Σg

+ (0,0)

band using two-photon Doppler-free

spectroscopy on rotationally-hot H2 to

obtain 0.005 cm-1 absolute accuracy. In

combination with the accurate values

for EF level energies, the rotational level

energies in the H2 X, v=0 ground state

were derived. Relativistic and QED

corrections are finally obtained from

comparison of the experimentally-

obtained ground state level energies with

the most accurate ab initio nonrelativistic

calculations. The extracted QED and

relativistic contributions to rotational

level energies, which can be as high as

0.13 cm-1, are found to be in perfect

agreement with most recent calculations

of QED and high-order relativistic effects

for the H2 ground state.

[1] E. J. Salumbides et al., Phys. Rev. Lett. 107,

043005 (2011).

12

I2

Scattering lens resolves nanostructure

A.P. Mosk1, E.G. van Putten1, D. Akbulut1,

J. Bertolotti1,2, G. Ctistis1, W.L. Vos1,

and A. Lagendijk1,3

1 Complex Photonic Systems, Faculty of Science

and Technology and MESA+ Institute for

Nanotechnology, University of Twente.

2 University of Florence, Dipartimento di

Fisica.

3 FOM Institute for Atomic and Molecular

Physics (AMOLF)

Scattering of light is usually seen as a

nuisance in microscopy, as it strongly

deteriorates the achievable resolution.

However, by gaining active spatial control

over the optical wave front we have

shown that it is possible to manipulate

the propagation of scattered light far in

the multiple scattering regime. These

wave front shaping techniques have given

rise to new high-resolution microscopy

methods [1,2]. This is based on the

realization that scattering by stationary

particles performs a linear transform-

ation on the incident light modes. By

inverting this linear transformation,

one can focus light through an opaque

material and even inside it, as shown in

Fig. 1. An extremely high resolution

focus can be obtained using scatterers

embedded in a high-index medium. We

have constructed a scattering lens made

of the high-index material Gallium

Phosphide (GaP) which has the highest

index of all nonabsorbing materials in

the visible range. This yields a focal spot

resolution of less than 100 nm, and it

seems theoretically possible to create a

focus of order 70 nm [1]. We will discuss

how the system resolution of a micro-

scope using this lens could be pushed

even higher.

[1] E.G. van Putten, D. Akbulut, J. Bertolotti,

W.L. Vos, A. Lagendijk, and A.P. Mosk,

Scattering Lens Resolves sub-100 nm

Structures with Visible Light, Phys. Rev.

Lett. 106, 193905 (2011).

[2] E.G. van Putten, A. Lagendijk, and A.P. Mosk,

Optimal concentration of light in turbid

materialsJ. Opt. Soc. Am. B 28, 1200 (2011).

Fig. 1: (a) A normal lens has a restricted numerical

aperture (NA), which limits the resolution with which

it can focus light. (b) Scattered light can reach the tar-

get point from any angle, effectively covering full NA.

The incident wave can be structured to force construc-

tive interference at the target.

13

O5 O6

Near-field investigation of localizedmodes in slow-light photonic crystalwaveguides

S.R. Huisman1, G. Ctistis1, J.L. Herek1,

S. Stobbe2, P. Lodahl2, W.L. Vos1,

P.W.H. Pinkse1

1 MESA+ Institute for Nanotechnology,

University of Twente, 2 DTU Fotonik , Denmark

Disorder in photonic-crystal slab wave-

guides can cause localization of light.

To study this phenomenon, a near-field

scanning optical microscope (NSOM)

is the ideal tool, because one can probe

light from any desired point along the

waveguide surface with sub-wavelength

resolution. We observe, decompose, and

analyze intricate mode structures in

GaAs photonic waveguides using a phase-

sensitive NSOM in the near IR. At the

band-edge for TE-like guided modes,

i.e. in the slow-light regime, narrowband

localized modes are observed for certain

frequencies, where the light is strongly

confined at random locations along

the waveguides. At these localized modes

light also extends out from the waveguide

axis.

Figure caption: NSOM image of the light in a

photonic-crystal waveguide

Signature of electromagnetically induced transparency in a plasmonicmolecule’s local density of optical states

Martin Frimmer, Toon Coenen, Femius

Koenderink

FOM Institute AMOLF

In quantum optics, electromagnetically

induced transparency (EIT) and Fano-

interference are two well known phenom-

ena relying on quantum interference.

Recently, similar interference was found

in the extinction of plasmonic oligomers

due to coupling of bright and dark states.

We present measurements of the local

density of states (LDOS) in plasmonic

heptamers, using luminescence induced

by local excitation in an electron micro-

scope. We find a spatial redistribution of

LDOS occurring exactly at the frequency

of EIT in extinction. On basis of this

data we present two views of plasmonic

EIT, which mirror the bare-state and

dressed-state interpretations of atomic

EIT. Firstly, we explain the interference

through near-field coupling of bare

states, defined in analogy to symmetry-

adapted vibrational modes of benzene.

Secondly, we identify true normal modes,

and show that plasmon EIT can be

viewed purely as interference on the

detector. Our findings facilitate the

design of plasmon antennas for molecu-

lar emission, absorption and sensing.

14

O7 O8

Mapping electromagnetic fields insidephotonic crystals

T. Denis, B. Reijnders, J.H.H. Lee,

P.J.M. van der Slot, K.J. Boller

Laser Physics and Nonlinear Optics, Mesa+,

University of Twente

Photonic crystals (PhC) offer an unpre-

cedented level of control over the proper-

ties of light. This control is at the heart

of numerous fundamental studies and

has far-reaching technological implica-

tions. Most of these applications rely

on the highly accurate periodicity of the

structure while others rely on disorder

in the PhC. To characterize a PhC, we

will present a method, applicable in the

microwave domain, which allows measur-

ing the electromagnetic fields inside

a PhC using a perturbation technique.

To demonstrate this method, we use a

sub-wavelength sized metal bead to

disturb the field in a PhC placed inside

a resonator. The bead induces a shift in

the resonant frequencies depending on

the local field at the position of the bead,

and this shift is measured. By varying the

bead’s position we can map the shape of

the electromagnetic field inside the PhC.

Although this method works at micro-

wave frequencies, the scale invariance

of Maxwell’s equations allows other

photonic structures to be scaled to the

microwave domain to measure the inter-

nal field.

Speckle correlation functions in plasmonics

Frerik van Beijnum, Jeroen Sirre,

Martin van Exter (Leiden University),

Chris Rétif (AMOLF)

The optical intensity transmitted through

a random pattern of subwavelength holes

in a metal film exhibits an intriguing

speckle-type pattern. We study the varia-

tion of this speckle pattern as a function

of wavelength. The resulting speckle

correlation function (SCF) is ideal to

study transmission processes of these

random patterns. We show that the

SCF has a wavelength independent back-

ground correlation, and a wavelength

dependent contribution, see figure. The

wavelength dependence is caused by

surface plasmons excited at one hole and

coupled out at another hole, while the

background correlation corresponds to

light transmitted directly through the

holes. These measurements yield, among

others, the propagation length of the

surface plasmons, and the scattering

losses induced by the holes.

15

O9 O10

Using atom lithography to create magnetic nanostructures

Thijs Meijer, Cornee Ravensbergen,

Edgar Vredenbregt, Ton van Leeuwen

Eindhoven University of Technology

In direct-write atom lithography, also

known as laser-focused deposition, atoms

are focused into a periodic pattern by a

standing light wave and deposited on a

substrate. The basis of this technology is

the dipolar interaction of near resonant

light with neutral atoms.

As the dipolar force is weak compared

to the electric or magnetic force used

to focus charged particles, atom litho-

graphy was assumed to work only for

laser cooled atom beams. We have shown

that it is possible to do atom lithography

with thermal beams of Fe atoms without

laser cooling if the geometry of the setup

is chosen well, creating geometric cooling

effects [1]. We will discuss the effects

of geometric cooling on the focusing

process. [2]

We will also present the magnetic

properties of Fe layers that are structured

using atom lithography in nanoline

arrays on a Fe background. We find un-

usual biaxial anisotropic magnetic

properties in these line arrays.

[1] Smeets et al. Appl. Phys. B., 98, 697-705,

(2010)

[2] Meijer et al. accepted for publication in

Appl. Phys. B.

Full characterization of NbN Nanodetectors

J.J. Renema1, G. Frucci2, Z. Zhou2,

F. Mattioli3, A. Gaggero3, R. Leoni3,

M.P. van Exter1, M.J.A de Dood1, A. Fiore2

1 UL,2 TU/E3 IFN, Rome

NbN Nanoscale Single/multiphoton

detectors consist of an NbN nanowire

with a subwavelength constriction.

Depending on bias current, this detector

has regimes with single and multiphoton

sensitivity.

The POVM formalism provides an

assumption-free method to characterize

an unknown detector system using a set

of coherent state inputs.

We obtain a full experimental characteri-

zation of the NbN NSMD by introducing

the Effective Photon POVM formalism,

an extension of the POVM formalism.

We show that this method recovers and

characterizes the multiphoton regimes.

Our aim is to use this formalism to

provide insight into the multiphoton

detection event.

The Effective Photon POVM formalism

takes into account the linear loss due

to finite absorption and subwavelength

size of the detector and separates it from

the nonlinear action of the detector. The

EP-POVM formalism naturally extends

the usual characterization of mulit-

photon detectors by their n-photon

slopes.

16

Evening lecture

The human factor in Climate Change

dr. Rob van Dorland

Royal Netherlands Meteorological Institute,

P.O.box 201, 3730 AE De Bilt, The Netherlands

The science of climate change tries to

find answers on three main issues. The

first issue is the detection of climate

change from instrumental records as well

as from proxy data, such as tree rings,

sediments and ice cores. Since 1979 the

climate system has been monitored using

satellite information, which are in princi-

ple radiation measurements in various

frequency bands from which relevant

climate parameters can be retrieved. The

attribution of observed climate change to

potential causes is the second key issue in

climate research. Over the past century

it concerns the ability to separate the

climate effects due to human activities

from the natural variability. This requires

knowledge of climate processes and their

mutual interactions. The third issue is

projection. The present uncertainties

result in a broad range of climate projec-

tions at the end of the 21st century.

About half of the projected range, 1.1 to

6.4 degrees in 2100 relative to 1990,

is caused by uncertainties in future

anthropogenic emissions, depending on

population growth, social economic

factors and technological developments.

The other half is due to uncertainties in

climate sensitivity. The state-of-the-art

information on detection, attribution

and projection will be presented.

17

I3

Spectroscopy of biological molecules incold ion traps: examples, challenges andperspectives

Thomas R. Rizzo

Ecole Polytechnique Fédérale de Lausanne

(EPFL), Switzerland

The combination of electrospray ion-

ization for putting large, biological

molecules in the gas phase together with

buffer-gas cooling in radio-frequency ion

traps opens the possibility to spectros-

copically probe cold, isolated molecules

of virtually any size. Given the ability to

do so raises the question of whether one

can extract useful information from the

spectra of such large systems. Despite the

simplification afforded by the restricted

number of thermally populated vibratio-

nal states at low temperature, the size

and conformational flexibility of large

biomolecules poses serious challenges

both to experiment and to the theoretical

analysis needed to extract information.

After describing the details of our experi-

mental approach [1], we give a few

examples of the kind of spectroscopic

information that we have obtained for a

series of peptides of increasing size and

complexity [2]. We then consider the

limiting factors for pushing these techni-

ques to significantly larger molecules

(e.g., small proteins) and how these

obstacles might be overcome. Finally we

show some of most recent results in

which we further simplify spectra by

adding a new “dimension” of ion mobili-

ty in which to sort large molecules before

spectroscopic interrogation.

[1] A. Svendsen, U. J. Lorenz, O. V. Boyarkin,

and T. R. Rizzo, Rev. Sci. Instrum. 81, 073107

(2010).

[2] T. R. Rizzo, J. A. Stearns, and O. V. Boyarkin,

Int. Rev. Phys. Chem. 28, 481 (2009).

[3] G. Papadopoulos, A. Svendsen,

O. V. Boyarkin and T. R. Rizzo, Faraday

Discussions 150, 243 (2011).

18

O11 O12

The Far-Infrared region as probe for the secondary structure of peptides

S. Jaeqx1, M. Schmitt2, W.J. van der Zande3,

and Anouk M. Rijs1

1 FOM Institute Rijnhuizen, Edisonbaan 14,

3439 MN, Nieuwegein, The Netherlands2 Institute for Physical Chemistry, Heinrich

Heine University, Düsseldorf, Germany3 Institute for Molecules and Materials,

Radboud University Nijmegen,

The Netherlands

Vibrational spectroscopy in combination

with DFT-calculations can predict struc-

tural properties of peptides. Usually the

focus is on the Amide A and B (NH

stretch), Amide I (C=O stretch) and

Amide II (NH ip bend) bands. The

promising region is the far-infrared

region, down to 100 cm-1, where back-

bone vibrations, e.g. skeletal torsion

and Amide IV and V bands, will reveal

more directly the secondary structure of

peptides. The detailed interpretation of

these spectra needs many experiments

and theory.

We study the conformation of gas phase

Z-Ala3-NHMe, a helix type, and

Z-Pro-OH, part of a γ-turn; structures

determined with the conventional

Amide I and II bands. The far-infrared

region measured with FELIX shows that

the Amide V band is sensitive to the

hydrogen bond environment and that

backbone vibrations are found.

Background-free nonlinear micro-spectroscopy with vibrational molecularinterferometry

Erik Garbacik1, Jeroen Korterik1, Cees Otto2,

Shaul Mukamel3, Jennifer Herek1,

Herman Offerhaus1

1 Optical Sciences group, MESA+ Institute,

University of Twente2 Medical Cell BioPhysics group, MIRA

Institute, University of Twente3 University of California, Irvine

Nonlinear vibrational microspectroscopy

techniques such as coherent anti-Stokes

Raman scattering (CARS) and stimulated

Raman scattering (SRS) are becoming

widely used for applications. However,

CARS and SRS each suffer from a variety

of background effects—non-resonant

contributions and fluorescence for the

former, photothermal lensing and

two-photon absorption for the latter—

that can make accurate interpretation

of the data difficult. To overcome these

problems we have developed a new

technique that features a pair of Stokes

Raman pathways interfering in the same

molecular level. This interference pro-

duces amplitude modulations on each of

the driving optical fields, which are then

detected with lock-in amplifiers. This

technique, in addition to being free of

non-resonant background, also allows us

for the first time to distinguish between

vibrational and electronic resonances in a

single measurement by monitoring the

relative gain and loss in each field.

19

O13 O14

Absorption by molecular oxygen in theatmospheric bands

Frans R. Spiering1, Maria B. Kiseleva2,

Nikolay N. Filippov2 and Wim J. van der

Zande1

1 IMM, RU Nijmegen

2 St. Petersburg State University, Russia

Oxygen plays an important role in satel-

lite retrieval studies and accurate oxygen

absorption predictions are needed.

Quantitative laboratory measurements

have to be made and ideally combined

with effective semi-empirical models of

line strengths and line forms. Several fac-

tors must be taken into account: Pressure

broadening, line mixing, rayleigh scatte-

ring, doppler broadening and a process

called collision induced absorption. For

this absorption, that takes place during a

collision, no theoretical predictions exist.

Using cavity ring-down spectroscopy, ini-

tially using a pulsed dye laser, but now a

CW diode laser, we retrieved the collision

induced absorption in both the A- (760

nm) [1] and B-band (680 nm) [2] for

pure oxygen and confirm aspects of line-

mixing. For the A-band we also retrieved

the collision induced for mixtures of oxy-

gen and nitrogen [3].

[1] The Journal of Chemical Physics, 133,

114305 2010

[2] Molecular Physics, 109, 2011, 535–542

[3] Phys. Chem. Chem. Phys., 13, 2011,

9616–9621

Probing the adsorption of carbon monoxide on transition metal clustersusing IR photodissociation spectroscopy

V.J.F. Lapoutre, J. Oomens and J.M. Bakker

FOM Institute for Plasma Physics Rijnhuizen

Carbon monoxide is involved in many

catalytic reactions, either as starting

material or side-product. It is therefore

of fundamental interest to understand

the binding of CO to catalytic materials,

for instance to transition metals. For

niobium, CO molecules bind dissocia-

tively to bulk material. However, despite

the recent interest in enhanced catalytic

activity of nanosized metal clusters, little

is known on the adsorption of CO on

niobium in the cluster regime.

We study the adsorption of CO on

gas-phase niobium clusters. Using far-IR

photodissociation spectroscopy in combi-

nation with mass-spectrometric detection,

a size-selective IR fingerprint is

obtained for cationic, neutral and

anionic clusters. The combination of

these spectra with DFT calculations

allows for the structural determination

of the adsorption product.

20

I4

Lattices of atom microtraps on magnetic-film atom chips

Robert J.C. Spreeuw


Institute of Physics, Universiteit van

Amsterdam

Lattices of microscopic atom traps offer

a wide range of opportunities for funda-

mental science as well as applications.

In our experiments we create arrays of

microtraps using a novel approach based

on patterned magnetic film on an atom

chip [1]. A major motivation for this

work is the development of a novel

Quantum Information science platform.

Atom chip technology allows a combina-

tion of the best of two worlds, on the

one hand neutral atoms with their

weak coupling to the environment and

concom-itant long coherence times,

and on the other hand the compactness

and large-scale integration possibilities

of solid-state like systems.

We review recent experiments demon-

strating several hundred atomic micro-

clouds on a magnetic-film atom chip,

each containing tens to hundreds of

atoms. The traps are optically resolved by

absorption imaging and can be addressed

individually. We demonstrate a shift

register by varying an external control

magnetic field. We cool a few hundred

microscopic clouds simultaneously to

the Bose-Einstein condensation phase

transition. Close to quantum degeneracy

density-dependent atom losses lead to

squeezing of the atom number variance

to a subpoissonian level [2].

We investigate the implementation of

theoretical ideas to create quantum

entanglement using controlled dipole-

dipole interaction between highly excited

Rydberg atoms in neighboring micro-

traps. Exciting Rydberg atoms close to the

chip surface has also enabled us to per-

form electrometry, i.e. to measure electric

fields emanating from (adsorbates on)

the chip surface [3]. Finally we investi-

gate the possibilities to scale down the

lattice parameter of our microtrap arrays

to well below optical wavelengths. This

would go beyond the limitation posed

by optical lattices, opening up new

parameter regimes for quantum simula-

tors [4].

[1] S. Whitlock, et al., New J. Phys. 11, 023021

(2009)

[2] S. Whitlock, et al., Phys. Rev. Lett. 104,

120402 (2010)

[3] A. Tauschinsky, et al., Phys. Rev. A 81, 063411

(2010)

[4] V.Y.F. Leung, et al., arXiv:1104.3067

21

O15 O16

Differential cross section measurementfor Inelastic scattering of CO with Ar/He

C.K. Bishwakarma, G. Sarma, J. Onvlee,

A.K. Saha, A.T.J.B. Eppink and D.H. Parker

Department of Molecular and Laser Physics,


6525 ED Nijmegen, The Netherlands

We measured state-to-state inelastic

differential cross sections of the CO

molecule colliding with Argon/He at 900

collision angle in a crossed molecular

beam experiment, using the velocity

map imaging (VMI) technique.

Rotational excitation of CO molecules

due to collisions with Argon/He is

probed by (2+1) resonance enhanced

multi-photon ionization spectroscopy.

Experimental differential cross sections

of the CO molecule provide an excellent

test case for high precision CO-Ar/He

potential energy surfaces and our

experiment broadens the understanding

of CO which is one of the most impor-

tant interstellar molecules.

FELIX user facility Nijmegen: advanced MIR/FIR sources

R.T. Jongma, A.F.G vand er Meer,1

B. Redlich,1 W.J. van der Zande

Institute for Molecules and Materials,


Heyendaalseweg 135, NL-6500 GL Nijmegen,

The Netherlands1 FOM Institute for Plasma Physics

“Rijnhuizen, Edisonbaan 14,

3439MN Nieuwegein, The Netherlands

FELIX, Free Electron lasers for Infrared

eXperiments, will become a new user

facility at the Radboud University.

Operation starts from 2013. We now

commission the first novel FEL instru-

ment, FLARE, operating in the THz

gap from 100 µm (3THz) to 1500 µm

(0.2 THz). We hope to show in Lunteren

first lasing of FLARE, which will not only

provide pulsed but also (many µsec) long

pulses of high spectral resolution. In

2012, the instruments FELIX I, FELIX II

and FELICE will move from Rijnhuizen to

the FELIX facility Nijmegen, such that we

can offer a wavelength range from 3 µm

to 1500 µm and can offer a large volume

with extreme IR intensities within the

FELICE cavity. With many thanks to all

coworkers, but also to NWO, FOM and

the RU for making the facility possible.

22

O17 O18

Intergalactic alcohol for detecting drifting constants

Paul Jansen1, Isabelle Kleiner2, Li-Hong Xu3,

Wim Ubachs1, and Hendrick L. Bethlem1

1 LaserLaB, VU University Amsterdam

2 LISA, CNRS UMR, Universités Paris 7 et

Paris Est

3 Department of Physics and Centre for Laser,

Atomic, and Molecular Sciences,

University of New Brunswick

Physical theories extending the

Standard Model have presented scenarios

that allow for, or even predict, spatio-

temporal variations of the constants of

nature, such as the proton-to-electron

mass ratio µ = mp/me. We found that

microwave transitions in methanol

molecules could act as sensitive probes

to determine whether the proton-to-

electron mass ratio does indeed vary[1].

Methanol is one of the most abundant

molecules in the interstellar medium

and is responsible for prominent radio

emission lines generated by astrophysical

masers. Here we explain the origin of the

high sensitivity of certain methanol lines.

Moreover we construct a simple model to

estimate the sensitivities of transitions in

methanol and other molecules. This

model not only simplifies the calculation

of sensitivities, but also explains why

methanol is probably the most suitable

target to probe variation of µ.

[1] Jansen et al. PRL, 106, 100801 (2011).

Ultrashort electron bunches from anultracold electron source

W.J. Engelen, N. Debernardi,

E.J.D. Vredenbregt, O.J. Luiten


We report on the development of an

electron source that produces ultrashort,

ultracold electron bunches. These bun-

ches are made by accelerating electrons

which are created by near-threshold

photoionization of a cloud of laser-cooled

atoms.

The bunches that are created from this

source will be used to perform single-

shot, ultrafast electron diffraction

(UED) experiments on crystals of macro-

molecules, such as proteins. This opens

the possibility to study the dynamics of

non-equilibrium structures with both

spatial and temporal resolution at the

atomic level (i.e. 1 nm and 100 fs).

To ensure high quality diffraction data,

the bunches should be sufficiently coher-

ent, with a transverse coherence length

of at least a few lattice spacings of the

crystal under investigation.

Here we present our experimental results

in making ultrashort, ultracold electron

bunches, with temperatures as low as

10 K and an expected pulse length in the

order of picoseconds. Such low tempera-

tures lead to an electron bunch with a

coherence length of tens of nanometers,

amply fulfilling the coherence length

requirement for diffraction experiments.

23

O19 O20

High-fidelity projective readout of a solid-state quantum register

Hannes Bernien1, Lucio Robledo1, Lilian

Childress2, Bas Hensen1, Paul F. A.

Alkemade1 & Ronald Hanson1

1 Kavli Institute of Nanoscience Delft

2 Bates College, Maine, USA

Spins in solids are very attractive candi-

dates for scalable quantum information

processing and quantum repeaters. Here,

we demonstrate preparation and single-

shot measurement of a multi-spin quan-

tum register[1]. We achieve high-fidelity

readout of the electronic spin of a

single nitrogen-vacancy (NV) centre in

diamond by harnessing resonant optical

excitation techniques. We exploit the

readout to project up to three nearby

nuclear spin qubits onto a well-defined

state. Conversely, we can distinguish the

state of the nuclear spins in a single shot

by mapping it onto and subsequently

measuring the electronic spin. Finally,

we show compatibility with qubit control

by demonstrating initialization, coherent

manipulation, and single-shot readout

in a single experiment on a two-qubit

register, using techniques suitable for

extension to larger registers.

In addition, we will discuss our latest

results towards entangling two distant

NV center by combining spin-photon

entanglement with two-photon quantum

interference.

[1] Nature (in press, 2011).

The effect of peptide length onVUV photofragmentation

O. Gonzalez-Magaña1, G. Reitsma1,

M. Door1, R. Hoekstra1, T. Schlathölter1

1 KVI University of Groningen

In a recent VUV photofragmentation

study [Bari S., et al. J. Chem. Phys. 134,

024314 (2011)], we observed fast loss

of the aromatic sidechain from the free

protonated peptide leucine enkephalin

(YGGFL) rather than statistical fragmen-

tation. Here we present a systematic

investigation of this sidechain loss chan-

nel in a series of synthetic peptides with

sequences YGnF (n=0,1,3,5,10), with

aromatic sidechains Yside and Fside only

and variable distance between the respec-

tive amino acids Y- and F. The yields of

Y and F related fragments dominate and

been determined as a function of peptide

length for a wide range of photon ener-

gies (see figure for Y). We observe that

even absorption on the G units along

the peptide backbone induce sidechain

loss. However, for large peptides (n=10),

internal vibrational redistribution (IVR)

quenches the fast loss channel.

24

I5

Quantum networks of trapped ions

C. Monroe

Joint Quantum Institute and

University of Maryland

Trapped atomic ions are among the

most promising candidates for quantum

informa-tion processing, with each atom

typically storing a single quantum bit

(qubit) of information in appropriate

internal electronic levels. All of the funda-

mental quantum operations have been

demonstrated between small numbers of

atoms [1], and the central challenge now

is how to scale the system to larger num-

bers of interacting qubits. The Coulomb

interaction between trapped ions allows

entangling operations through the collect-

ive motion of the ion crystal, which is

excited through the state-dependent opti-

cal dipole forces. Such a quantum network

may be limited in size by the stability and

coherence of the motion of larger ion

crystals, and current efforts are devoted

to the physical movement of individual

atomic ions through complex ion trap

structures [2] or alternatively by mapping

qubits onto photons that can allow the

probabilistic entanglement between

remotely-located atomic crystals [3]. On

the other hand, when such a laser force

is applied globally, an effective spin-spin

interaction emerges whose sign and range

can be precisely controlled with the laser

[4], and any possible spin correlation

function can be measured with standard

state-dependent fluorescence techniques.

This allows the quantum simulation of

interesting spin models that possess non-

trivial ground states for the investigation

of quantum phase transitions, quantum

frustration, and the emergence of spin

liquid behavior. Work on all of these

fronts will be reported, including quantum

simulations of magnetism with N = 16

atomic qubits as well as progress on opera-

ting deterministic gates between atoms

separated by macroscopic distances.

[1] R.Blatt and D.J. Wineland, Nature 453, 1008

(2008).

[2] D. Kielpinski et al., Nature 417, 709 (2002).

[3] L.M. Duan and C. Monroe, Rev. Mod. Phys. 82,

1209 (2010).

[4] R. Islam et al., Nature Comm. 2, 377 (2011).

25

P1 P2

Real-time breath analysis by OpticalParametric Oscillator based Off-Axisintegrated cavity output spectroscopy

Denis D. Arslanov, Simona M. Cristescu,

and Frans J.M. Harren

Life Science Trace Gas Research Group,

Molecular and Laser Physics, Institute for

Molecules and Materials, Radboud University,

P.O. Box 9010, NL-6500 GL Nijmegen,

the Netherlands

Breath analysis is an attractive and

promising field in medicine, because it

is a non-invasive and safe diagnostic

method. Diseases and metabolic disor-

ders will change the gas composition of

exhaled breath. Here we demonstrate that

the combination of a continuous wave

singly-resonant Optical Parametric

Oscillator pumped by a fiber-amplified,

fast-scanning diode laser and Off Axis

Integrated Cavity Output Spectroscopy is

a powerful tool for rapid and sensitive

trace gas detection. Real-time detection

of ethane in exhaled human breath

during free exhalations was carried

out and is combined real-time multi-

component gas detection of ethane,

methane and water breath. The system

was able to record a 17 cm-1 wide

spectrum at 3 micrometer in 1 s. As a

result of this the real-time detection of

acetone, a large molecule with a wide

absorption spectrum, became possible

in exhaled breath at sub-second time

resolution (0.4 s).

Julija Bagdonaite1, Wim Ubachs1,

Michael Murphy2, Lex Kaper1,3

1 Vrije Universiteit Amsterdam2 Swinburne University of Technology,

Melbourne3 Universiteit van Amsterdam

Observations of H2 spectra in the line-

of-sight of distant quasars may reveal a

variation of the proton-to-electron mass

ratio at high redshift, typically for z > 2.

The wavelength of each individual spec-

tral line in the Lyman and Werner band

systems of H2 depends in a different way

on this mass ratio. It means that if any

variation of the proton-to-electron mass

ratio has occurred in the distant past of

the Universe, it would have been imprin-

ted as systematic achromatic shifts of the

H2 lines. Thus, to experimentally search

for the variation a comparison is made

between highly accurate laboratory spec-

tra and quasar spectra.

In this poster we review the status of

investigations into variation of the pro-

ton-to-electron mass ratio from analyses

of highly redshifted H2 absorption

systems.

Novel searches for cosmological variation of the proton-to-electron mass ratio from high-redshift H2 absorbers in quasar spectra

26

P3 P4

IR Structural Characterization ofTransition Metal Carbene Cations: Ta, W, Ir, Pt

Joost M. Bakker1, Vivike Lapoutre1,

Andrew Sweeney2, Abhigya Mookerjee2,

Peter B. Armentrout2

1 FOM Institute for Plasma Physics Rijnhuizen,

Nieuwegein, The Netherlands2 University of Utah, Salt Lake City, UT

Methane is a key fossil fuel that is pre-

sently underutilized because it is difficult

to transport. This problem could be sol-

ved by conversion of methane to other

chemicals. Several third-row transition

metal (TM) cations readily activate

methane to form TM+CH2, a transition

metal carbene. A fundamental under-

standing of these carbene complexes is

of crucial importance to understand the

chemistry behind the activation process

and their role in industrial processes

such as the Shell higher olefin reaction.

The geometric and electronic structures

of such simple species have yet to be

experimentally examined, although theo-

ry suggests several competing candidates.

Here, we investigate the structure of

four TM carbene ions formed upon

the interaction between gas-phase TM

cations and methane using infrared (IR)

multiple photon dissociation (IRMPD)

spectroscopy.

Background-free and Doppler-reduced direct frequency comb spectroscopy of Rubidium atoms using coherent control

I.Barmes, S. Witte, J. Morgenweg, T.J. Pinkert

and K.S.E. Eikema

LaserLaB Amsterdam, VU University,

Amsterdam, the Netherlands

A new method of direct frequency comb

excitation of a two-photon transition is

presented. Background-free signal of the

5s-7s two-photon transition in 85Rb has

been produced by applying a V-shaped

spectral phase to the spectrum of a

Ti:sapphire frequency comb. The applied

spectral phase temporally separates the

'red' and 'blue' parts of the comb

spectrum. When the shaped pulses are

focused through the Rb-cell and reflected

back, only combinations of counter-

propagating blue and red pulses excite

the transition in the cell, while excitation

from two co-propagating photons

(producing a Doppler-broadened back-

ground) is eliminated. Due to the band-

width of the pulses a residual Doppler

width remains comparable to the natural

linewidth (a few MHz). With this

method we reached a relative accuracy

of about 10-11, which is 4 times better

than previous experiments. One of the

applications we envision is direct

vacuum-ultraviolet comb excitation of

a two-photon transition in helium.

27

P5 P6

Large-Area Pulsed Laser Deposition ofthin films with atomic precision

H.M.J. Bastiaens1, K. Orsel1, R. Groenen2,

G. Koster2, J. van Dijk3, A.J.H.M. Rijnders2,

K.J. Boller1

1 Laser Physics and Nonlinear Optics

2 Inorganic Materials Science Mesa+,

University of Twente,Enschede

3 Elementary Processes in Gas

Discharges,Eindhoven University

Pulsed Laser Deposition (PLD) is a

versatile technique to deposit complex

materials. However, most knowledge on

the PLD process is based only on empiri-

cal research examining what parameters

appear to provide the best result with a

specific material and setup. The goal of

our research is to progress towards an

improved understanding and control

of PLD for scaling up to large area depo-

sition while maintaining full control on

film growth, i.e. to the level of atomic

precision. We plan to combine in-situ

growth studies with in-situ plasma

diagnostics to understand the complete

PLD process. To map the spatial and

temporal development of the plasma we

will use a combination of Laser Induced

Fluorescence and Absorption

Spectroscopy.

For ablation of the target material we

will use a unique XeCl excimer laser

which has an adjustable pulse length and

a nearly diffraction limited beam quality.

It allows to investigate novel ranges of

PLD parameters that could not be

explored so far.

Up-scaling high-harmonic generation in a capillary

H.J.M. Bastiaens, F.F. Sterl, A. Strooisma,

S.J. Goh, Y. Tao, P.J.M. van der Slot,

K.J. Boller

Laser Physics and Nonlinear Optics, Mesa+,


The optical properties of EUV free-

electron lasers can be improved by see-

ding the laser. Capillary based high-

order harmonic generation (HHG)

sources have shown to provide the requi-

red beam quality for seeding such lasers.

To show that such a system can also

produce the high pulse energy required

for seeding, we have performed a numeri-

cal scaling study, where we calculate how

the relative high-order harmonic energy

increases with the capillary diameter and

gas pressure. However, as the capillary

diameter is increased, more gas will flow

into the surrounding vacuum where it

would lead to detrimental absorption of

the generated EUV radiation. It is there-

fore extremely important to keep the

amount of neutral gas encountered by

the EUV radiation to a minimum. As a

preparation for a large-diameter, HHG

source, we experimentally studied the

flow dynamics of such a system. Here we

present results from the scaling study and

from the experimental study on the flow

dynamics of large diameter capillaries.

28

P7 P8

Reflectance Tuning at ExtremeUltraviolet (EUV) Wavelengths withActive Multilayer Mirrors

Muharrem Bayraktar1, Chris J. Lee2,

Fred A. van Goor1, Gertjan Koster1,

Guus Rijnders1, Fred Bijkerk1,2

1 MESA+ Institute for Nanotechnology,

University of Twente (NL)

2 FOM Institute for Plasma Physics Rijnhuizen

(NL)

At extreme ultraviolet (EUV) wavelengths

the refractive power of transmission type

optical components is limited, therefore

reflective components are used. Reflective

optics (multilayer mirrors) usually con-

sist of many bilayers and each bilayer is

composed of a high and a low refractive

index material to maximize the partial

reflection from the interface. For each

bilayer composition, the reflectance is

dependent on the wavelength and the

incidence angle. Here we propose an acti-

ve multilayer mirror structure which can

tune its reflectance with external voltage.

The active multilayer mirror is designed

to work at EUV lithography wavelengths

(around 13.5 nm) in normal incidence

configuration by combining Mo/Si multi-

layer mirrors, a piezoelectric active layer,

a buffer layer and electrodes as shown in

the figure. Optimization of the structure

for maximum reflectance tuning will be

explained for different types of light

sources by considering the fabrication

process.

Deceleration and trapping of heavy diatomic molecules for precision measurements

J.E. van den Berg, , J.R. Meinema and

S. Hoekstra

KVI - TRIµP, Rijksuniversiteit Groningen

We are building a novel type of Stark

decelerator to decelerate and trap heavy

diatomic molecules, such as SrF, in

order to prepare a dense sample of cold

molecules that can be used for precision

measurements on fundamental symme-

tries. The ring-shaped electrodes of the

decelerator create a moving trapping

potential which initially moves with the

speed of a supersonic beam of SrF and

is then brought to a standstill. Particle

trajectory simulations have been used to

analyze the deceleration and trapping

efficiency, showing that the ring deceler-

ator, for SrF in the (J,M) = (2,0) state,

outperforms traditional and alternate-

gradient Stark decelerators by at least

an order of magnitude. We plan to

combine Stark deceleration with laser

cooling to arrive at a final temperature

of ~200 microKelvin.

29

P9 P10

Rydberg Crystals

R.M.W. van Bijnen, S. Smit,

K.A.H. van Leeuwen, E.J.D. Vredenbregt,

S.J.J.M.F. Kokkelmans


Recently there has been a surge of inte-

rest on the topic of Rydberg atoms in

cold atomic gases, due to their extra-

ordinary high dipole moments, leading

to a high sensitivity to electric fields, and

strong Van der Waals interactions.

In practice however, it is difficult to

reliably excite more than a handful of

Rydberg atoms in an atomic cloud. Once

one atom is excited to the Rydberg state,

it can shift the energy levels of thousands

of its neighbours such that they are no

longer resonant with the excitation laser.

Moreover, it is hard to control the precise

location of the excitations.

However, we show that such problems

can be circumvented by adiabatically

varying the frequency and intensity of

the laser used to excite the atoms.

Employing a tailored laser chirp, it is

possible to create high numbers of

regularly spaced Rydberg excitations,

forming a crystalline structure inside a

cold atomic gas.

Velocity map Imaging study of the photodissociation of X–O2 (X = Xe, C2H4

and C6H6): O(1D) detection

Bin Yan,Zahid Farooq, Andre Eppink,

Wim van der Zande and David H. Parker

Radboud University Nijmegen

In order to investigate the effect of a

local environment on the light absorp-

tion of molecular oxygen, we prepared

X-O2 Van der Waals clusters in a super-

sonic expansion and studied the photo-

dissociation of these clusters. Previous

studies in the 220-270 nm region showed

several cluster-induced dissociation

channels, but only one going to the 2nd

dissociation limit (O(3P) + O(1D)). In

this work the product O(1D) fragment

was directly probed around 205nm using

REMPI in combination with Velocity Map

Imaging (VMI). We confirm that the 2nd

dissociation limit is clearly active only for

C6H6-O2 clusters, and find that cluste-

ring affects the Rydberg structure of O2

for Xe-O2, shifting states into resonance

at the dissociation wavelength.

Figure 1. Typical images

30

P11 P12

Electron transfer in collisions of highlycharged ions with Na(3s) and Na*(3p)

Blank1, S. Otranto2, C. Meinema1,

R. E. Olson3, R. Hoekstra1

1 KVI, Atomic Physics, University of Groningen,

The Netherlands

2 Universidad Nacional del Sur, Argentina

3 Missouri University of Science and

Technology, USA

Single electron transfer in collisions of

highly charged N5+ and Ne8+ keV ions

with ground state Na(3s) and laser

excited Na*(3p) has been investigated

both experimentally and theoretically.

The projectile energies are varied from

1 to 10 keV/amu which includes the

matching velocity of the valence electron.

State selective cross sections and scatter-

ing angle distributions are obtained using

recoil-ion momentum spectroscopy. The

target is provided by magneto-optically

cooled Na atoms.

A strong dependence of the differential

cross sections on the collision energy is

observed. Scattering angle spectra reveal

different transfer mechanisms for highly

excited final states at low collision ener-

gies. The results are compared with

Classical-Trajectory Monte Carlo

(CTMC) calculations and show an

overall very good agreement.

Spin drag in a Bose Gas

P.C. Bons, S.B. Koller, A. Groot, R.A. Duine,

H.T.C. Stoof, P. v.d. Straten

Nanophotonics Utrecht

Spintronics is the field focussing on

transport of spin rather than charge.

Spin drag is an effect where a relative

velocity between different spin compo-

nents induces a force. In an ultra-cold

atomic transport experiment we observe

spin drag in a Bose gas [2].

We prepare a non condensed cloud with

two equally populated spin states.

In a first experiment an external force is

applied on only one spin species and the

relative displacement is monitored as a

function of time. In a second experiment

a damped mutual oscillation of the two

spin species is observed.

Approaching the phase transition to BEC,

spin drag is observed to be Bose enhan-

ced as predicted by a recent theory [1],

while in fermionic systems spin drag is

Pauli blocked at low temperatures.

Our results pave the way for transport

studies of degenerate bosons that are very

different from fermionic systems.

[1] R.A. Duine, H.T.C. Stoof Spin Drag in

Noncondensed Bose Gases, PRL 103 170401

[2] S.B. Koller, A. Groot, P.C. Bons, R.A. Duine,

H.T.C. Stoof, P. v.d Straten Spin drag in a

Bose Gas ArXive

31

P13 P14

Two- and three-body loss of spin-polarized metastable helium atomsin an optical dipole trap

J. S. Borbely, R. van Rooij, S. Knoop and

W. Vassen

LaserLaB Vrije Universiteit, Amsterdam

We have studied the stability of ultracold

spin-polarized metastable helium-4

(4He*) in an optical dipole trap as a

function of magnetic field up to 400 G.

We cool 4He* towards quantum degene-

racy in a cloverleaf type magnetic trap,

transfer the atomic cloud into a crossed

optical dipole trap at 1557 nm and pre-

pare a pure sample of atoms in either the

m=+1 or m=-1 spin state by an RF sweep.

Our data provides the first experimental

confirmation of the theoretical predic-

tion of a strong increase of two-body

losses above 100 G for m=+1 [1], which

limits the lifetime of the trapped sample

at high magnetic fields. In a cloud of

m=-1 atoms two-body losses are energetic-

ally not allowed and the lifetime is only

limited by three-body loss, which is

magnetic field independent for both

m=+1 and m=-1.

[1] G. V. Shlyapnikov, J. T. M. Walraven,

U. M. Rahmanov, and M. W. Reynolds

Phys. Rev. Lett. 73, 3247 (1994).

Ethylene detection quantum cascadelaser based OFF-AXIS integrated cavityoutput spectroscopy

R. Centeno, J. Mandon, S.M.Cristescu,

F.J.M. Harren

Life Science Trace Gas Facility, IMM,


Ethylene plays an important role in many

aspects of plant growth and development.

Among its effects are promoting fruit

ripening and revealing stress responses

in plants. In horticulture, the ethylene

production needs to be controlled during

shipments, which requires fast, simple

and sensitive gas detectors. Here, we

propose the combination of a Quantum

Cascade Laser (QCL) with off-axis

alignment integrated cavity output

spectroscopy (OA-ICOS) for the detec-

tion of ethylene. To access the strongest

absorption properties of ethylene, a

pulsed QCL is used. This laser allows

system integration, thus ensuring fast

and sensitive measurements. OA-ICOS

takes advantage of long path absorption

spectroscopy, thereby eliminating the

common problems of resonance with

other cavity-based absorption techniques

and reducing the complexity of the setup.

Application of this technique aims for

the development of a detector platform

for the detection of trace gasses at the

sub part-per-billion volume (1:109) level.

This will provide advanced and compact

spectroscopic gas sensors for the future

research of different volatiles.

32

P15 P16

Coherent control in single-crystallinegold nanoantennas

Ting Lee Chen, Dirk-Jan Dikken,

Jorick van’t Oever, Jeroen Korterik,

Frans Segerink, Herman Offerhaus,

Jennifer Herek

Mesa+ Institute for Nanotechnology,


The interaction of broadband coherent

radiation with metallic nanostructures

gives rise to “hot spots” of field intensity.

Our aim is to visualize and manipulate

these hot spots. The two-photon photo-

luminescence (TPPL) of noble metals is

used to visualize plasmonic modes on

nanoantennas, such as the dipole

antenna or bowtie antenna. We employ

a scanning confocal microscope with

~300 nm resolution to detect the peak

positions of TPPL from hot spots in the

nanostructures, which are fabricated

by focused ion beam milling on single

crystalline gold flakes. Further, we have

constructed a state-of-the-art polariza-

tion shaping setup to fully control the

spectral amplitudes and phases of TM

and TE polarization ultrafast optical

pulse. Combining the confocal TPPL

microscope with polarization shaped

pulses, we show the influence of the

spectral phase (TE & TM polarizations)

on the plasmonic spatial modes of the

gold nanostructures.

Optimization of the current extracted from an ultracold ion source (UCIS)

N. Debernardi, R.W.L. van Vliembergen,

W.J. Engelen, M.P. Reijnders,

K.H.M. Hermans, P.H.A. Mutsaers,

E.J.D. Vredenbregt and O.J. Luiten

Department of Applied Physics,


The UCIS is based on creating very cold

ion beams (T < 1 mK) by near-threshold

photo-ionization of a laser-cooled and

trapped 85Rb gas. The UCIS has the

potential of producing ion beams with a

brightness and current comparable to the

liquid-metal ion source (LMIS), which is

the current state-of-art for focused ion

beam (FIB) technology. The reduced

brightness characterizes the source

performance. A dynamic model of the

source describing its properties under

pulsed operation has been developed

and experiments have validated it. A

maximum average current of 13 pA have

been measured (limited by the ionization

laser power). A current of 100 pA, ideal

for FIBs, is possible to be achieved.

33

P17 P18

EF1Σg+ - X1Σg

+ two-photon precisionstudies in hot H2

G. D. Dickenson1, E.J. Salumbides1,2,

M.L. Niu1 and W. Ubachs1

1 LaserLaB, Vrije Universiteit, Amsterdam2 University of San Carlos, Cebu City,

The Philippines

We are currently re-investigating the

EF-X system in hydrogen (and its iso-

topes HD and D2) by means of Doppler-

free spectroscopy in a REMPI scheme.

In view of testing novel ab initio calcula-

tions, including non-adiabatic, relativistic

and QED effects, we are exploring a

wealth of v and J quantum states. Such

exotic quantum states are populated by

means of a photo-chemical reaction with

HBr and HI. In a first exploration round

of measurements we use a frequency-

converted pulsed dye-laser yielding accu-

racies of 0.05 cm-1. Several rovibronic

progressions are analysed and strong

perturbations are highlighted. These

results form a stepping stone toward

performing ultra-precise measurements

using more narrowband sources and

frequency combs for calibration, with the

goal to test QED effects in molecules.

Femtosecond pump-probe coincidenceimaging in molecular photodynamicsstudies

Mohammad Fanood, Niels Ligterink,

Maurice H.M. Janssen

LaserLaB Amsteram and Chemistry

Department, Vrije Universiteit Amsterdam,

De Boelelaan 1083, 1081 HV Amsterdam,

The Netherlands

Pump-probe technique is one of the most

commonly used methods to investigate of

photodynamics of atoms and molecules

where the probe pulses detect the dynam-

ics induced in the system by the pump

pulses and ionization signal is recorded

as a function of delay time between two

pulses. On the other hand, to obtain

the complete information of photo-

dissociation and ionization experiments,

the photo-electron/photo-ion velocity

map coincidence imaging technique is

used. With this technique it is possible

to obtain the complete energetic cor-

relations and angular/energy resolved

distributions.

In this work, ultrafast photodynamics

in CH3I was studied by combining a

two-colour (UV/Visible) pump-probe

technique together with the coincidence

imaging. The UV pulses are created by

Sum Frequency Mixing of the output of

a NOPA with the 800 nm output of a

Ti:Sapphire laser. The range of UV pulses

we can create is between 510 – 535 nm.

The visible pulses are generated with

another NOPA and tuned between

530-550 nm.

34

P19 P20

Unraveling the electronic structure of monodehydrogenated PAH ions with FELIX

Héctor Alvaro Galué1 and Jos Oomens1,2

1 FOM Institute for Plasma Physics

“Rijnhuizen”, Edisonbaan 14,

3439MN Nieuwegein, The Netherlands2 University of Amsterdam, Science Park 904,

1098XH Amsterdam, The Netherlands

An important fraction of cosmic carbon

is believed to be locked up in the form of

gas-phase polyaromatic hydrocarbon

(PAH) molecules. In interstellar space,

a PAH is subject to the strong UV star-

light which can photo-evaporate one or

more of its peripheral hydrogens. Using a

Paul ion trap, we produce three different

mono-dehydrogenated PAH ions and

probe their electronic structures

employing the free electron laser for

infrared experiments (FELIX).

Stability study of high-harmonic generation in a capillary for seeding offree-electron lasers

S.J. Goh1, Y. Tao1, P.J.M. van der Slot1,

H.J.M. Bastiaens1, S.G. Biedron4,

M.B. Danailov3, S.V. Milton4, J. Herek2,

K.J. Boller1

1 Laser Physics and Nonlinear Optics2 Optical Sciences, Mesa+,

University of Twente3 FERMI@Elettra,Sincrotrone Trieste

S.C.p.A.,Italy4 Colorado State University,USA

We study the beam characteristics of a

high-harmonic source for seeding of the

free-electron laser FERMI@Elettra. The

stability requirements for seeding include

pointing stability, divergence and energy

jitter. These parameters are important

due to the large distance between the

source and the undulator where the seed

needs to overlap with the electrons.

High-harmonic generation (HHG) in a

capillary has several advantages over gas

jet and gas cell. It is the only source that

has demonstrated wavelength selective

enhancement of a single harmonic by

adaptive shaping of the drive pulse.

Furthermore, the highest conversion

efficiency in HHG has been shown using

a capillary. Here, we present the beam

properties of high-order harmonics

generated in a Argon and Xenon-filled

capillary, driven by a Ti:Sapphire laser

with 35 fs pulses. We will compare

our experimental results with the require-

ments of the FERMI@Elettra laser.

35

P21 P22

Pump-probe photofragmentation of atrapped isolated peptide

O. Gonzalez-Magaña1, G. Reitsma1,

M. Door1, O. Versolato1, R. Hoekstra1,

B. Fischer2, N. Camus2, R. Moshammer2,

J. Ullrich2, T. Schlathölter1

1 KVI University of Groningen 2 MPIK , Germany

Dissociation dynamics in large biomole-

cules are dominated by slow charge

migration triggered processes and much

faster breakup involving e.g. repulsive

molecular states. It was recently predicted

[P. Nat. Acad. Sci. 103 (2006) 6793]

that in very small peptides, upon

photoionization charge migration due

to electron correlation can occur on

fs-timescales. To observe such processes

experimentally, we employed two succes-

sive intense 10 fs IR-pulses from the

MPIK Ti:sapphire laser system to photo-

ionize and dissociate the isolated peptide

leucine-enkephalin with a variable pulse

delay. It can be seen in the figure that

the tyrosine sidechain fragment Yside

dominates the spectrum, and that this

process peaks at a delay of 700 fs whereas

corresponding larger fragments peak at

800 fs.

First and second sound in a weakly interacting Bose gas

A. Groot, P.C. Bons, S.B. Koller and P. van der

Straten

Nanophotonics, Debye Institute for

Nanomaterials, Princetonplein 1, Utrecht

First and second sound are the hallmarks

of two fluid hydrodynamics. First and

second sound are mainly density modula-

tions in the non-condensed and conden-

sate fractions of an ultra-cold bosonic

gas, respectively. These two sound modes

are weakly coupled, leading to an avoided

crossing at very low temperatures. To

investigate the dispersion relation of

these sound modes, two approaches are

followed. In one, a dimple is induced in

the potential creating a travelling sound

wave. In a second experiment, a standing

sound wave is induced by periodically

modulating the trapping potential. From

these experiments the sound speed and

therefore the dispersion relation is

extracted via phase contrast imaging and

singular value decomposition.

Figure. Standing sound wave pattern for two different

modulation frequencies.

36

P23 P24

Spectroscopic evidence for oxazolonestructures in anionic b-type peptidefragments

Josipa Grzetic, , Jos Oomens

FOM Rijnhuizen

Collision induced dissociation tandem

mass spectrometry has become an essen-

tial tool in proteomics as it is used to

determine peptide sequences. The combi-

nation of tunable infrared lasers with

tandem mass spectrometers made possi-

ble recording IR spectra of CID peptide

fragments, revealing their molecular

structure and giving insight into the

dissociation chemistry.

Here we present the IR spectra of the b2

fragments of deprotonated AlaAlaAla and

AlaTyrAla and they suggest an oxazolone

structure for both peptides.

Deprotonation is shown to occur on

the oxazolone α-carbon, which leads to

a conjugated structure in which the

negative charge is practically delocalized

over the entire oxazolone ring, providing

enhanced gas-phase stability.

Laboratory study of Rayleigh-Brillouinscattering for measuring the winds ofthe Earth

Z. Gu, M.O. Vieitez, W. Ubachs

Institute for Lasers, Life and Biophotonics,

VU University Amsterdam

An experimental study is carried out to

determine the Rayleigh-Brillouin line

shape in air and in different gases for a

range of pressures between 0.3 and

3 bar and at various temperatures.

Measuruments are performed in the

ultraviolet (365 nm) at a 90 degrees

scattering angle. The obtained line

shapes are compared with the so-called

TENTI-6 model, the current paradigm

for the RB-lineshape. This model had

only been tested for a very small subspace

of gases, pressures and temperatures.

This project is intimately connected to

future missions of the ESA, in particular

the ADM-Aeolus mission, aiming at

establishing the global wind profile over

the Earth.

37

P25 P26

Sensitive fluorescence detection using a camera from the gaming industry

B. L. Van Hoozen1, J. P. Korterik1,

K. G. de Bruin, W.B. Nagengast, J. L. Herek1,

H. L. Offerhaus1

1 Optical Sciences group, MESA+ Institute for

Nanotechnology, University of Twente,

PO box 217, 7500AE Enschede,

The Netherlands

2 Netherlands Forensic Institute, Mobile

Forensic Team, Laan van Ypenburg 6,

2497 GB The Haag, The Netherlands

3 University Medical Center Groningen,

Dept. of Gastroenterology and Hepatology,

Hanzeplein 1, 9713 GZ Groningen,

The Netherlands

The detection limit for linear (fluor-

escence) and nonlinear (stimulated

fluorescence or Raman) imaging can be

improved by reducing noise. One way to

reduce the noise in these types of ima-

ging is to modulate the signal at a certain

frequency and only detect signals at that

frequency. Since most noise sources have

a 1/f dependence, higher modulation

frequencies result in less noise. Typically

cameras used for imaging have frame

rates of 50 or 100 Hz; however, a new

time-of-flight camera developed for

the gaming industry has a modulation

frequency of 20 MHz, allowing for a

substantial reduction in noise.

Structure and magnetism of terbium clusters

Jeroen Jalink,1 Chris van Dijk,1 John Bowlan,2

Saurabh Ghosh,3 Theo Rasing,1

Walt de Heer,2 Mikhail Katsnelson,1

Olle Eriksson,4 Joost Bakker,5 Biplab Sanyal,4

and Andrei Kirilyuk1

1 Radboud University Nijmegen

2 Georgia Institute of Physics

3 Cornell University

4 Uppsala University

5 FOM Institute Rijnhuize

Structural and magnetic properties of

clusters differ considerably from their

bulk aggregate. Their magnetic properties

are sensitive to atomic and electronic

structure and quantum size effects.

Generally, as cluster behavior is changed

on a single-atom level and combined

with the non-linear evolution of proper-

ties, clusters are both fundamentally

intriguing and technologically important.

Presented is experimental and theoretical

work on terbium clusters. The magnetic

moments, measured in the gas phase

using a Stern-Gerlach deflection experi-

ment, correspond well with the values

from LDA+U calculations. Furthermore,

the vibrational spectra are measured

using FELICE for further confirmation of

the calculated conformations.

38

P27 P28

Towards an ultracold mixture of metastable helium and rubidium

Steven Knoop, Hari Prasad Mishra,

Wim Vassen

Organisatie

LaserLaB Vrije Universiteit, Amsterdam

We present our plans to set up an experi-

ment to produce an ultracold atomic

mixture of metastable He (3He* or4He*) and 87Rb. Our cooling strategy is

based on a two-species MOT loaded from

a Zeeman slower for He* and a 2D-MOT

for Rb, forced evaporative cooling of Rb

and sympathetic cooling of He* in a

magnetic trap, and forced evaporative

cooling in a 1557-nm crossed optical

dipole trap. We will search for interspe-

cies Feshbach resonances, which will be

used to control the interaction between

the He* and the Rb atoms or associate

ultracold He*Rb molecules. The main

motivation is the detection of He*Rb2

Efimov trimers. The large mass ratio

between the two atomic species results in

a dramatic reduction of the spacing

between successive Efimov states, allo-

wing a first experimental test of the peri-

odicity of the Efimov spectrum [1].

[1] F. Ferlaino and R. Grimm, Physics 3, 9 (2010)

SuperGPS through optical networks’ forfundamental science and innovation

J.C.J. Koelemeij1, T.J. Pinkert1, L. Willmann2,

K.S.E. Eikema1,2, K. Jungmann2,

and W. Ubachs1

1 LaserLaB, VU University Amsterdam

2 KVI, University of Groningen

1950s inventions such as atomic clocks

and transistors have revolutionized socie-

ty, and enabled technologies such as the

Internet and GPS. However, over the past

decade new optical technologies (e.g.high-capacity fiber-optic data communi-

cation, optical clocks) have replaced their

electronic predecessors (copper wire,

microwave atomic clocks) as the state of

the art. Today, advances in high-accuracy

frequency dissemination through existing

optical fiber networks may trigger the

next step of this electronic-to-optical

paradigm shift. Time and frequency

dissemination through optical fiber net-

works may provide an important backup

for GPS, and even surpass GPS as a more

reliable and accurate means for time

transfer and positioning. In addition,

optical frequency transfer facilitates

searches for ‘new physics’ (e.g. time-

varying fundamental constants). As

part of a FOM program aimed at such

fundamental physics tests, an optical

fiber link Amsterdam-Groningen has

recently been provided by SURFnet to

VU and KVI, enabeling to take the first

steps towards ‘SuperGPS through optical

networks’.

39

P29 P30

Molecular hydrogen ions, the proton-electron mass ratio and the proton size

J.C.J. Koelemeij, J. Biesheuvel, F.M.J. Cozijn,

J.B. Wolf, and W. Ubachs

LaserLaB, VU University Amsterdam

The molecular hydrogen ions

(H2+, HD+, etc.) consist of three elemen-

tary particles, which interact according

to the laws of QED. Recently, theorists in

the field have advanced the QED descrip-

tion of the molecular hydrogen ions to

an accuracy level at which fundamental

particle properties, such as the proton-

electron mass ratio and the proton size,

contribute substantially to the inaccuracy

of calculated level energies. Comparisons

of theoretical level calculations with

accurate spectroscopic data can therefore

lead to improved values of fundamental

particle properties, as well as stringent

tests of QED. As molecular hydrogen ions

possess long-lived rovibrational states,

they are amenable to the most accurate

spectroscopic technique to date, namely

optical spectroscopy of laser-cooled ions

stored in a trap. Here we report progress

towards a new determination of the

proton-electron mass ratio, based on

high-resolution rovibrational laser

spectroscopy of laser-cooled HD+, and

towards measurement of the proton size

through radiofrequency spectroscopy of

HD+ hyperfine intervals.

Discovery of electron-hole Cooper pairs ina semiconductor

A.J. van Lange1, M.A.M. Versteegh1,

D. van Oosten1, H.T.C. Stoof2 and

J.I. Dijkhuis1

1 Debye Institute for NanoMaterials Science2 Institute for Theoretical Physics,

Utrecht University

Using a femtosecond laser we excite bulk

zinc oxide cooled to liquid helium temper-

atures. In the excited semiconductor an

electron-hole plasma is created. We

monitor the luminescence spectra of

the plasma. In these spectra we find the

signature for so-called electron-hole

Cooper pairs, analogous to the electron-

electron Cooper pairs in superconductors.

Using quantum many-body theory we

calculate the optical gain spectra of an

electron-hole plasma and the critical

temperatures for Cooper pair formation

in bulk zinc oxide. We find excellent

agreement with the experiment. Never

before have electron-hole Cooper pairs

been observed in a semiconductor.

40

P31 P32

Compact/Low Power RF Technology forTime Resolved Electron Microscopy

A. Lassise, P.H.A. Mutsaers, O.J. Luiten


Here we report on the theory, design,

and testing of a compact power efficient

alternative for femtosecond electron

bunch creation without the use of lasers.

A high repetition train of femtosecond

electron bunches are created by streaking

an incoming DC electron beam with a

transverse magnetic field in a cavity

across a slit or aperture. If streaking

is large in comparison to the slit, the

electrons passing through will have a

temporal length in the sub-picosecond

regime.

The cavity is capable of creating a

magnetic field of 2 mT with only 3.5 W,

all in a 3.5 cm diameter cylindrical die-

lectric filled cavity. This is achieved by

the low loss tangent and high relative

permittivity of the dielectric.

The cavity with 3.5 W input power

followed by a slit of 25 µm at 5 cm dis-

tance, creates a regular train of bunches,

each with a time resolution of 350 fs.

The cavity has been mounted, tested, and

characterized in an augmented 30 keV

SEM table top beam line.

Photoelectron-photoion coincidenceimaging of ultrafast control in multichannel molecular dynamics

Carl Stefan Lehmann, N. Bhargava Ram,

Daniel Irimia and Maurice H.M. Janssen

LaserLab and Department of Chemistry,


The control of multichannel ionic

fragmentation dynamics in CF3I is

studied by femtosecond pulse shaping

and velocity map photoelectron-photoion

coincidence imaging. When CF3I is

photoexcited with femtosecond laser pul-

ses around 540 nm there are two major

ions observed in the time-of-flight mass

spectrum, the parent (CF3I) ion and the

fragment (CF3) ion.

In this contribution we focus on the

influence of LCD-shaped laser pulses

on the molecular dynamics. The three-

dimensional recoil distribution of

electrons and ions were imaged in

coincidence using a single time-of-flight

delay-line detector by fast switching of

the voltages on the various velocity map

ion lenses. These results demonstrate that

a simplification of a coincidence imaging

apparatus is possible.

We show that shaped laser fields like

chirped, double and multiple pulses can

enhance the CF3+/CF3I+ ratio by up to

100%. The total energetics are revealed by

analysis of the coincident photoelectron

spectra and the kinetic energy of the

CF3+ and I fragments.

41

P33 P34

Lattices of atom microtraps on magnetic-film atom chips

V.Y.F. Leung, A. Tauschinsky,

and R.J.C. Spreeuw


Institute of Physics,

University of Amsterdam

We discuss the latest progress of our

experiments with atomic microclouds on

a magnetic-film atom chip [1]. So far we

have demonstrated a shift register by

varying an external control magnetic

field, and cooled a few hundred micros-

copic clouds simultaneously to quantum

degeneracy, where density-dependent

atom losses lead to squeezing of the atom

number variance to a sub-Poissonian

level [2]. More recently, we have also

demonstrated spatially resolved, coherent

excitation of Rydberg atoms [3].

A recently completed next-generation

chip facilitates the continuation of our

experiments at trap separations of 10

micron. Scaling down even further,

we propose two different strategies for

developing a quantum information

science platform. One aims for meso-

scopic ensemble qubits in a lattice of ~5

micron period, and the other for direct

quantum simulators using sub-optical

lattices of ~100 nm period [4].

[1] S. Whitlock, et al., New J. Phys. 11, 023021

(2009)

[2] S. Whitlock, et al., PRL 104, 120402 (2010)

[3] A. Tauschinsky, et al., PRL 81, 063411 (2010)

[4]V.Y.F. Leung, et al., arXiv:1104.3067

Towards Bose-Einstein condensation in a 1D box on an atom chip

W. Lewoczko-Adamczyk, P. Wicke, and

N.J. van Druten


University of Amsterdam

Box-like potentials on an atom chip are

promising for studying one-dimensional

(1D) quantum gases [1]. The magnetic

trapping potential of our chip features

strong confinement in the radial direc-

tion combined with steep walls enclosing

the trap in the axial direction. Unlike in

a harmonic trap, the axial density distri-

bution in a box is homogeneous which

allows for exact theoretical treatment

without a need for approximations like

the local-density approximation.

Moreover, with each experimental run,

individual atomic samples are observed

rather than averages over thousands,

typical for an optical lattice.

We characterize the potential roughness

due to imperfection of the chip wires and

discuss strategies to flatten the bottom of

the trap. Care is also taken to eliminate

any optical effects that could distort the

1D density distribution during imaging.

Currently we are able to load the box

with ultracold (below 1 µK) atoms

prepared for further evaporative cooling

towards Bose-Einstein condensation.

[1] J.J.P. van Es et al, J. Phys. B 43, 155002 (2010)

42

P35 P36

CO ice photodesorption; a wavelength-dependent study

Harold Linnartz1, Edith Fayolle1,

Mathieu Bergin2, Claire Romanzin2,

Xavier Michaut2, Karin Öberg3,

and Jean-Hugues Fillion2

1 Sackler Laboratory for Astrophysics,

Leiden Observatory2 Laboratoire de Physique Moléculaire,

Université Pierre et Marie Curie, Paris3 Harvard-Smtithsonian Center for

Astrophysics, Cambridge

UV-induced photodesorption of ice is a

non-thermal evaporation process that

explains the presence of cold molecular

gas in space. Information on the average

UV photodesorption yield of astrophysi-

cally important ices exists for UV broad-

band experiments. UV fields around, e.g.,

low-mass pre-main sequence stars are

dominated by specific atomic and mole-

cular emission lines that may affect the

photodesorption process in different

ways. Here the wavelength-dependent

photodesorption of pure CO ice is presen-

ted between 90 and 170 nm. The experi-

ments are performed using tunable syn-

chrotron radiation (SOLEIL-DESIRS). Ice

photodesorption is simultaneously probed

by infrared absorption spectroscopy and

by quadrupole mass spectrometry. The

experimental results reveal a strong wave-

length dependence directly linked to the

vibronic transition strengths of CO ice,

implying that photodesorption is induced

by electronic excitations. The observed

dependence on the ice absorption spectra

implies relatively low photodesorption

yields at 121.6 nm (Lyα), compared to

the high yields found for transitions into

the first electronic state of CO (A1Π).

A QCL-based sensor for exhaled NO analysis

J. Mandon1, M. Högman2, P. J.F.M. Merkus3,

J. van Amsterdam4, F.J.M. Harren1,

S.M. Cristescu1

1 Life Science Trace Gas Facility,

Radboud University, Nijmegen, NL2 Respiratory Medicine and Allergology,

Uppsala University, Gävle, SW3 Dept. of Pediatrics, Radboud University

Medical Centre, Nijmegen, NL4 Laboratory for Health Protection Research,

Bilthoven, NL

Fractional exhaled Nitric Oxide (FENO)

is an indicator in the diagnostic and

management of asthma. Up to now,

despite the availability of standardized

procedures, numerous ways to collect

breath samples and several NO sensors

have been reported. The aim of this study

is to compare currently used commercial

analyzers with Quantum Cascade Laser

based wavelength modulation spectro-

scopy.

The QCL-based detector, offering sub-

ppbv (sub-part-per-billion by volume)

detection limit, is facing a commercial

chemiluminescent analyzer and a porta-

ble hand-held electrochemical sensor.

A study was performed on 20 children,

aged 6-16 years, who received diagnosis

of asthma. The data analysis validated the

advantages and efficiency of laser-based

sensors for FENO measurements (single

or multiple flows analysis), e.g. the

accuracy, precision, sensitivity and

reproducibility of our optical sensor.

43

P37 P38

Nitric oxide detection based on Off-Axisintegrated cavity output spectroscopy

D. Marchenk, J. Mandon, S. M. Cristescu,

F. J. M. Harren


Nitric Oxide (NO) is known as an

atmospheric pollutant, as well as an indi-

cator of airway inflammation and next-

generation devices are needed to monitor

NO in a more robust and simpler way.

Here we propose a simple setup (Fig. 1)

based on continuous wave quantum

cascade lasers (QCL) using off-axis

Integrated Cavity Output Spectroscopy

(OA-ICOS). In this work, we used a high

finesse cavity (F~3100) to yield an effec-

tive optical path length of 181 m. At the

moment, with the QCL output power

of 3 mW and a relatively compact setup

a detection limit of ~2 ppbv (part per

billion by volume =1:109) of NO in N2

for a response time of 1s is achieved.

Further improvements, including wave-

length modulation technique, are

discussed.

Fig. 1 Schematic diagram of the QCL based OA-ICOS

experimental setup

Absolute density-profile measurementof molecular beam by using multiphotonionization of Xe

Congsen Meng, Daniel Irimia and

Maurice H.M. Janssen

LaserLaB Amsteram and Chemistry

Department, VU University Amsterdam,

De Boelelaan 1083, 1081 HV Amsterdam,

The Netherlands

We present a simple method to calibrate

the density-profile of supersonic molecu-

lar beam, which is obtained by compa-

ring the ion signal intensity between the

molecular beam and bulk gas under the

identical experimental conditions using

MPI of Xe and velocity map imaging

setup for Xe+ ions. This method relies on

the fact that ions of interest are produced

from the same interaction volume in

both cases.

In determining the absolute density

profile, issues like thermal broadening in

the bulk gas are dealt with using selective

discrimination of ion counts near the

image center along the laser propagation

direction. Details of the experiment are

presented in this contribution.

44

P39 P40

Programmable pulse sequences for XUV frequency comb spectroscopy atkHz-level accuracy

J. Morgenweg, I. Barmes, T. J. Pinkert,

K.S.E. Eikema


Parametric amplification and subsequent

high-harmonic upconversion of frequen-

cy comb laser pulses has been demonstra-

ted to transfer the accuracy of comb

lasers to the extreme ultraviolet (XUV)

[Kandula et al., PRL 2010]. We designed

a new system to generate phase-coherent

XUV pulse sequences with a programma-

ble delay well into the microsecond

range, and with a few attosecond timing

accuracy. This programmable pulse delay

will allow 'synthetic multi-pulse' comb

spectroscopy in the XUV (thereby exten-

ding the method beyond single-transition

recording), and will lead to an improve-

ment of the frequency accuracy to the

kHz level. To realize these goals a new

front-end for the pump laser of the

parametric amplifier has been developed,

employing 'bounce' amplifier technology

in combination with fast modulators.

Atom-light interactions in photonic nanostructures

B.O. Mussmann, A.J. van Lange, R. Pos,

and D. van Oosten

Debye Institute for NanoMaterials Science,

Utrecht University

Subwavelength sized metal and dielectric

structures can be used to locally enhance

light-matter interactions[1,2]. We describe

ways in which such structures can be used

to manipulate ultracold atoms[3]. We will

discuss the fabrication of suitable struc-

tures using e-beam lithography/lift-off

and focused ion beam milling. Furthermore,

we will report on the progress on the con-

struction of our experimental apparatus.

[1] M. Burresi, T. Kampfrath, D. van Oosten,

J. C. Prangsma, B. S. Song, S. Noda, and

L. Kuipers, Phys. Rev. Lett. 105, 123901 (2010)

[2] J. C. Prangsma, D. van Oosten, R. J. Moerland,

and L. Kuipers, New J. Phys. 12, 013005 (2010)

[3] D. van Oosten and L. Kuipers, Phys. Rev. A 84,

011802 (2011)

Photograph of the apparatus under construction

45

P41 P42

High precision UV measurements in CO, towards a laboratory test of the time-invariance of µ

Adrian J. de Nijs, Wim Ubachs

and Hendrick L. Bethlem


The metastable a3Π state of CO has been

found to have favourable properties for

testing the time-invariance of physical

constants. Due to an incidental degene-

racy between the J=8, Ω=0 and the J=6,

Ω=1 states the 2-photon microwave

transition connecting these two states

is highly sensitive to a possible time-

variation of physical constants. We are

planning a molecular beam experiment

to measure this transition.

As a first step, spectroscopic measure-

ments have been performed on the

a3Π → X1Σ+ transition. We have recorded

several transitions in 12C16O, 13C16O

and 12C18O at a MHz precision,

corresponding to a relative accuracy

of 10-10. The measured isotope shift

confirms the calculated sensitivity to a

possible variation of µ.

Coherent soft-X-ray microscopy usingfew-cycle laser pulses

Daniel Noom, Stefan Witte, Kjeld Eikema


X-ray imaging is an attractive tool for

many areas of science, ranging from

physics to biology. The use of short-wave-

length radiation in the soft-X-ray regime

enables a much higher resolution than

conventional microscopes. By exploiting

inner-shell absorption edges, one can

achieve element-specific contrast.

Soft-X-ray microscopy would be very

interesting for the study of e.g. ultrafast

dynamics in condensed matter samples,

while the ‘water-window’ wavelength

range (2-4 nm) would enable imaging of

water-immersed biological samples at

unprecedented resolution.

We present our efforts towards the

development of a table-top X-ray micro-

scope which is based on high-harmonic

generation of intense ultrashort laser

pulses, combined with lens-less imaging

techniques such as Fourier-transform

holography.

Long-wavelength radiation produced by

a parametric amplifier will be used to

achieve phase-matched generation of

high-harmonics down to 2 nm. This

unique laser system may also be useful

for e.g. seeding of X-ray free-electron

lasers. A major advantage of our laser-

based microscope is the availability of

laser pulses that are perfectly synchro-

nized to the X-ray pulse, enabling pump-

probe experiments with unprecedented

time resolution.

46

P43 P44

Atomic parity violation: Ra+

M.Nuñez Portela, H. Bekker,

J.E. van den Berg, O. Böll, U. Dammalapati,

G.S. Giri D.J. van der Hoek, K. Jungmann,

W. L. Kruithof, C.J.G. Onderwater, B. Santra,

R.G.E. Timmermans, O.O. Versolato,

L.W. Wansbeek, L. Willmann, H.W. Wilschut

Kernfysisch Versneller Instituut,

University of Groningen

The Ra+ ion is an ideal candidate for

high precision experiments. Atomic Parity

Violation (APV) can be measured in a

single trapped and laser cooled Ra+,

enabling a precise measurement of the

electroweak mixing angle in the Standard

Model of particle physics. As an impor-

tant step towards such experiments,

laser spectroscopy of short-lived radium

isotopes in a linear Paul trap has been

performed. The Hyperfine Structure of

the 6d2 D3/2 states[1] and Isotope Shift

of the 6d2 D3/2-7p2P1/2 transition [2]

have been measured in order to provide

benchmarks for the required atomic

theory, in particular of the atomic wave

funcions.

[1] O. O. Versolato et al. Phys. Lett. A 375 (2011)

3130-3133

[2] G. S. Giri et al. Phys. Rev. A 84 (2011)

020503(R)

Single-shot femtosecond electron diffraction

P.L.E.M. Pasmans, S.F.P. Dal Conte,

T. van Oudheusden, O.J. Luiten


Ultrafast electron diffraction (UED)

enables the study of the dynamics of

non-equilibrium structures, like phase

transitions and conformation changes,

with both spatial and temporal resolution

at the atomic level (~0.1 nm and ~100

fs). To acquire a diffraction pattern of

sufficient quality, typically 106 electrons

are required. So far in UED experiments,

multiple shots are used to build up a

high-quality diffraction pattern, limiting

the applicability of UED to reversible

processes. Single-shot operation requires

packing ~106 electrons in a single bunch.

Unfortunately, the strong repelling

Coulomb forces inevitably broaden the

bunch.

In our setup, we accelerate electron

bunches to 100 keV and reverse the

bunch expansion by injection onto the

oscillatory field sustained in a radio-

frequency (RF) cavity. In this way, we

have realized sub-100 fs, 100 fC, 100 keV

electron bunches, which thus fulfill all

requirements for single-shot femtosecond

electron diffraction. Using only a single

electron bunch, we have demonstrated

single-shot diffraction on a variety of

thin films.

Currently, we are optimizing our setup

and we are performing our first pump-

probe time-resolved UED experiments.

47

P45 P46

Towards ultra-stable frequency combsfrom NIR to XUV wavelengths

T. J. Pinkert, I. Barmes, J. Morgenweg,

A. Ruehl, and K. S. E. Eikema


At LaserLaB, we recently demonstrated

high-precision frequency comb metrolo-

gy, ranging from kHz-level measurements

in the near-infrared (NIR) [1] to record

high accuracy at the MHz-level in the

extreme ultraviolet (XUV) [2].

Considerable improvements are feasible if

the optical linewidths of the employed

frequency combs can be reduced from the

current values of about 1 MHz. For this

purpose, an ultra-stable CW laser system

at ~1550 nm with an estimated linewidth

of about 1 Hz is currently under develop-

ment. It will serve as a new optical

reference, and will also be used for

dissemination of reference frequencies

through fiber-networks. The system based

on a diode laser locked to a high-finesse

cavity further includes amplification,

frequency conversion and distribution

stages to simultaneously cover the

wavelengths of our fiber (Er,Yb) and

Ti:sapphire frequency combs. We expect

to reduce their optical linewidths by

several orders of magnitude.

[1] R. van Rooij et al., Science 333, 196 (2011)

[2] D.Z.Kandula et al., PRL 105, 063001 (2010

Towards ultra-stable frequency combsfrom NIR to XUV wavelengths

T. J. Pinkert, I. Barmes, J. Morgenweg,

A. Ruehl, and K. S. E. Eikema


At LaserLaB, we recently demonstrated

high-precision frequency comb metrolo-

gy, ranging from kHz-level measurements

in the near-infrared (NIR) [1] to record

high accuracy at the MHz-level in the

extreme ultraviolet (XUV) [2].

Considerable improvements are feasible if

the optical linewidths of the employed

frequency combs can be reduced from the

current values of about 1 MHz. For this

purpose, an ultra-stable CW laser system

at ~1550 nm with an estimated linewidth

of about 1 Hz is currently under develop-

ment. It will serve as a new optical

reference, and will also be used for

dissemination of reference frequencies

through fiber-networks. The system based

on a diode laser locked to a high-finesse

cavity further includes amplification,

frequency conversion and distribution

stages to simultaneously cover the

wavelengths of our fiber (Er,Yb) and

Ti:sapphire frequency combs. We expect

to reduce their optical linewidths by

several orders of magnitude.

[1] R. van Rooij et al., Science 333, 196 (2011)

[2] D.Z.Kandula et al., PRL 105, 063001 (2010

48

P47 P48

Photoelectron spectroscopy of chiralmolecules using pulse shaping and coincidence imaging

N. Bhargava Ram, C.S. Lehmann

and M.H.M. Janssen

LaserLaB and Physical Chemistry,


Chiral molecules are a special class of

molecules that come in two versions –

left and right handed form. Many amino

acids and pharmaceutical drugs are

chiral. Existing techniques to distinguish

and characterize chirality are based on

‘circular dichroism’, where the difference

in the absorption coefficient of the chiral

sample for the left and right circularly

polarized light is measured. This differ-

ence is typically 0.01 %. It was predicted

in the 1970’s that one-photon ionization

of chiral enantiomers using left and right

circularly polarized light would yield a

strong forward-backward asymmetry in

the photoelectron angular distribution.

Photoelectron circular dichroism in many

chiral molecules was measured using

synchrotron sources in the last few years

revealing asymmetries to the tune of

20 %.

To explore whether the chirality effects

from one-photon ionization can be furt-

her enhanced with respect to sensitivity

and selectivity by ultrafast multiphoton

excitation, we have initiated photoioniza-

tion experiments on chiral molecules

using femtosecond lasers with pulse

shaping capability and the powerful

coincidence imaging technique. Details

of recent work on this front will be

presented.

Fragmentation dynamics of polycyclicaromatic hydrocarbons after keV ionirradiation

G. Reitsma1, R. Hoekstra1, T. Schlathölter1,

R. Brédy2, L. Chen2, J. Bernard2, S. Martin2

1 KVI Atomic Physics, University of Groningen2 LASIM

The IR emission features of the interstel-

lar medium are generally attributed to

fluorescence emission of Polycyclic

Aromatic Hydrocarbons (PAHs). The

abundance of these PAHs significantly

influences the evolution of interstellar

gas and hence their origin and evolution

is a key question in astrophysics. After

a pioneering study on ion-PAH inter-

actions, at the KVI we have recently

built a setup in which we can study the

reaction dynamics of PAHs under ener-

getic ion irradiation. A supersonic jet is

seeded with PAHs and crossed with a

beam of highly charged ions in a recoil

ion momentum spectrometer. With this

apparatus, the 3D vector of the different

reaction products can be obtained. We

will present the first promising results

for ion collisions on anthracene.

The system does not allow us to deter-

mine the energy which is deposited into

the molecule before fragmentation. To

obtain this complementary information

we performed the CIDEC method on

anthracene-proton collisions at LASIM

université Lyon. An almost complete

picture of fragmentation channels and

corresponding excitation energy distribu-

tions was obtained and will be presented.

49

P49 P50

Numerical optimization of broadband CARS

A.C.W. van Rhijn, A. Jafarpour, M. Jurna,

J.L. Herek, and H.L. Offerhaus

Optical Sciences group, MESA+ research

institute, University of Twente

We explore the customization of (ultra-

short) light pulses for the detection and

imaging of specific chemical compounds.

Specifically we look at optimal phase

shaping strategies for a Coherent

AntiStokes Raman Scattering (CARS)

microscope that uses (degenerate)

broadband pump and probe pulses and

a narrowband Stokes pulse. By pre-

optimizing the spectral phase ϕ(λ) of the

broadband pulses with an evolutionary

algorithm, we find pulse shapes that can

selectively excite a compound of interest

in a mixture of resonant components,

where the predicted contrast ratios vary

from 100:1 up to 2200:1. Furthermore

we investigate the effects of noise in

the optimization and the effect of mixing

of the CARS signals within the focal

volume.

Figure caption: Selective excitation based on spectral

phase shaping.

Nature’s energy source probed by IR spectroscopy:Can ATP act as a fuel in the gas phase?

Anouk M. Rijs2, Jeffrey D. Steill1,

and Giel Berden2

1 Combustion Research Facility,

Sandia-California

2 FOM Institute for Plasma Physics Rijnhuizen

The main energy source that powers

many processes in mammalian cells is

adenosine 5’-triphosphate (ATP). ATP is

mainly used to fuel biomolecular motors,

which are, for example, involved in

muscle contraction, and active cargo

transport between cells. To perform their

function, these biomolecular motors

convert ATP into directed mechanical

motion. This biomolecular motion is

initiated by conformational changes at

the active site of these motorproteins,

and is induced by the association and

subsequent hydrolysis of ATP into ADP.

To fully understand the biological energy

production (hydrolysis of ATP to ADP),

both the photodissociation pathways as

well as detailed structural information of

ATP and its dephosphorylation products

ADP, AMP and cAMP have been obtained

by performing IR multiple-photodissocia-

tion (IRMPD) spectroscopy. In this

contribution we will elaborate on two

important issues; (i) does gas phase

dissociation follow the by nature selected

biochemical pathway and (ii) does the

favorable ATP structure which associates

to the hydrophobic active site coincides

with the isolated structures.

50

P51 P52

Spectroscopy of the 1s2s 3S1 – 1s2s 1S0

transition in quantum degenerate helium

R. van Rooij1, J.S. Borbely1, J. Simonet1,2,

M.D. Hoogerland1,3, K.S.E. Eikema1,

R.A. Rozendaal1, W. Vassen1

1 LaserLaB, VU University Amsterdam2 ENS, Paris3 University of Auckland

We have measured the extremely weak

IR transition between the two metastable

states in helium [1] to a precision of 8

parts in 1012, three orders of magnitude

more precise than state-of-the-art QED

calculations provide. Trapping the atoms

in an optical dipole potential at ultralow

temperatures allows for the long inter-

action times (up to 6 seconds) required

to excite this transition. A 1.5 micron

fiber laser, referenced to a frequency

comb, provides both the excitation beam

as well as the optical dipole trap.

Transition frequencies for 3He and 4He

were measured at the kHz level. Our

results agree with present-day QED theo-

ry of the absolute ionization energies of

the metastable states, which is accurate

to the MHz level, and poses a significant

challenge for theorists to calculate

higher-order terms. Through the isotope

shift the 3He nuclear charge radius was

deduced to be 1.961(4)fm.

[1] R. van Rooij et al., Science 333, 196 (2011).

Extending the frequency coverage ofmulti-heterodyne spectroscopy

Axel Ruehl1, Marco Marangoni2,

and Kjeld S. E. Eikema1

1 LaserLaB, VU University Amsterdam,

The Netherlands2 Politechnico di Milano, Italy

Multi-heterodyne spectroscopy with a

pair of detuned frequency combs allows

simultaneous measurement of absorption

and phase shift experienced by thousands

of comb lines [1]. So far, measurements

were only done at the laser wavelengths

limiting its versatility. Here, we propose

experiments to overcome this major

obstacle. The basis of our set-up are two

low-noise fiber frequency combs with

subsequent generation of highly coherent

tunable Raman solitons [2]. With these

tunable sources, the accessible spectral

range already spans from 1.1 to 1.8 µm.

In particular, when shifted to 1.5 µm and

further amplified, we observed up to 150

µW per comb mode which is sufficient

to perform saturation spectroscopy at the

P(5) to P(20) rovibrational transitions of13C2H2. Frequency conversion to the

molecular fingerprint region can be car-

ried out by difference frequency genera-

tion in Gallium Selenide crystals.

Numerical simulations predict mW-level

offset-free frequency combs covering

3 – 11 µm.

[1] Coddington et al., PRL 100, 013902 (2008)

[2] Ruehl et al., PRA 84, 011806 (2011)

51

P53 P54

State-to-state differential cross sectionsfor inelastic scattering of ND3 with Ar and He

A.K. Saha, C.K. Bishwakarma,

S.Y.T. van de Meerakker, A.T.J.B. Eppink

and D.H. Parker

Molecular and Laser Physics,

IMM Radboud University Nijmegen

The pumping mechanism of the ammo-

nia molecule in the interstellar medium

can be attributed to radiative and colli-

sional excitation. Astrophysical models

of these environments heavily rely on

theoretical calculations of collision cross

sections that depend themselves on the

accuracy of the potential energy surface.

Experimental measurement of differential

cross sections (DCS) is the best tool to

check the accuracy of the interaction

potential between molecules. In this

experiment the initial single rotational

state has been prepared using a hexapole

state selector. We measured state-to-state

inelastic DCSs of the ND3 molecule

colliding with Argon and He in a crossed

molecular beam experiment, using the

velocity map imaging (VMI) technique.

Rotational excitation of ND3 molecules

due to collisions with Argon and He is

probed by (2+1) resonance enhanced

multi-photon ionization spectroscopy.

Devasena Samudrala1, Elena Crespo1,

Simona M. Cristescu1, Nicole M. Van Dam2,

Frans J.M. Harren1

1 Life Science Trace Gas Facility

IMM Radboud University Nijmegen2 Ecogenomics, Radboud University Nijmegen

Proton Transfer Reaction Mass spectro-

metry (PTR-MS) has emerged as a useful

tool by allowing rapid, on-line detection

of trace gases from various chemical

groups with detection in the order of

seconds and detection sensitivity at the

(sub) parts per billion volume level.

PTR-MS is a soft ionization technique

and ionizes very efficiently larger volatile

organic compounds (VOCs) in air. The

method is used to detect on-line VOCs

emitted from roots of Brassicaecae plants

under attack of cabbage root fly larvae.

Several sulphur containing compounds

and glucosinolate breakdown products,

thiocyanates and isothiocyanates were

emitted by roots in response to infesta-

tion. The most typical marker for rapid

responses were mass 60 and m49, which

were identified as thiocyanicacid and

methanethiol. The identification and

dynamic patterns of the responses may

help to design non-invasive analytical

procedures to asses root infestations.

Real-time analysis of sulphur containing volatiles

emitted from larvae-infested Brassica plants using

Proton Transfer Reaction Mass spectrometry

52

P55 P56

Digital holographic imaging of latentfingerprints

R.J.T. Scheers, M. Bayraktar, C.J. Lee,

P.J.M. van der Slot, K.J. Boller

Laser Physics and Nonlinear Optics,

Mesa+ Institute for Nanotechnology,


Fingerprints patterns are used as impor-

tant evidence in forensic investigations.

Traditional acquisition methods that

unambiguously retrieve the fingerprint

pattern destroy or contaminate other

trace evidence concealed within the

fingerprint residue.

Here, we demonstrate proof-of-principle

digital holographic imaging of latent

fingerprints, which provides a non-

destructive and in-situ image of latent

fingerprints. We digitally recorded holo-

grams of fingerprint patterns in an

off-axis Michelson interferometer in

reflection geometry. The images of the

fingerprints were reconstructed numeri-

cally using the discrete Fresnel transfor-

mation (see reconstructed example

below). Further investigations, such as

the effect of absorption of laser light by

fingerprint residue on the contrast of the

reconstructed images, will be reported.

Fourier Microscopy of single plasmonicand metamaterial nanoscatterers

Ivana Sersic, Christelle Tuambilangana

and Femius Koenderink

FOM Institute AMOLF

Plasmonic and metamaterials nano-

scatterers are excellently suited building

blocks for realizing sub-wavelength

optical components, such as antennas

that convert near-field to far-field light.

The angular distribution of scattered light

is essential for operation of such anten-

nas. While cross-sections of these nano-

scatterers exceed their geometrical area,

small absolute cross-sections make

measuring the angular distribution of

scattering from single objects a challenge.

We report an experimental technique for

quantifying the angular distribution of

light scattered by any single nanoscatterer.

Our dark-field microscope consists of a

supercontinuum white light laser coupled

to an acousto-optical filter for wave-

length selection. The sample is excited by

means of total internal reflection and the

angular distribution of scattered light is

retrieved from microscope back-aperture

imaging. We report on a variety of

plasmonic and metamaterial structures,

including spit ring resonators (SRR), that

are expected to have interesting radiation

patterns due to the existence of mutually

cross-coupled magneto-electric polariz-

abilities.

53

P57 P58

Polarization-dependent ponderomotivegradient force in a standing wave

P. W. Smorenburg, J. H. M. Kanters,

A. Lassise, G. J. H. Brussaard, L. P. J. Kamp,

and O. J. Luiten

Applied Physics, Coherence and Quantum

Technology, Eindhoven University of

Technology

The ponderomotive force is derived for

a relativistic charged particle entering

an electromagnetic standing wave with a

general three-dimensional field distribu-

tion and a nonrelativistic intensity, using

a perturbation expansion method. It is

shown that the well-known pondero-

motive gradient force expression does

not hold for this situation. The modified

expression is still of simple gradient form,

but contains additional polarization-

dependent terms. These terms arise

because the relativistic translational

velocity induces a quiver motion in the

direction of the magnetic force, which is

the direction of large field gradients.

Oscillation of the Lorentz factor effecti-

vely doubles this magnetic contribution.

The derived ponderomotive force genera-

lizes the polarization-dependent electron

motion in a standing wave obtained

earlier. Comparison with simulations in

the case of a realistic, non-idealized,

three-dimensional field configuration

confirms the general validity of the

analytical results. For details, see

Smorenburg et al., Phys. Rev. A 83, 063810

(2011).

Ionization and fragmentation of free oligonucleotides by kev ions andsoft x-ray photons

M. Tiemens1, O. Gonzalez-Magaña1,

G. Reitsma1, M. Door1, S. Bari2, R. Hoekstra1,

R. Wagner3, M. Huels3, T. Schlathölter1

1 KVI University of Groningen2 Max Planck Advanced Study Group, CFEL,

Germany3 Department of Nuclear Medicine and

Radiobiology, University of Sherbrooke,

Canada

To study the direct effect of biological

radiation damage, the ionization and

fragmentation dynamics of isolated gas

phase DNA building blocks by energetic

photons and keV ions has been exten-

sively investigated. For the first time, we

performed a comparative study on the

fragmentation of more complex free

doubly protonated oligonucleotides

GCAT and GTAT upon ionization by keV

ions and soft X-ray photons. No influ-

ence of the location of the ionization

site on fragmentation is observed. The

molecules almost completely disintegrate,

with PO3H2+ and protonated nucleobases

dominating the fragmentation spectra;

the latter suggests intra-molecular hydro-

gen abstraction during the glycosidic

bond cleavage.

54

P59 P60

Design of a high quality radially polarized light at 405 nm using thinmetal film circular grating

K. Ushakova, S.F. Pereira, H.P. Urbach

Optics Research Group,

Delft University of Technology

On the last decade, radially polarized

light possessing high degree of circular

symmetry and purity has attracted in-

tense attention due to applications in

tight focusing, material processing and

optical tweezers. We show the design of a

high quality radial polarization formation

for wavelength of 405 nm by means of a

thin metal film diaphragm compound

of sub wavelength concentric nanoslit

grooves. A three-stage optimization of

the diaphragm geometry characteristic

parameters (film thickness, pitch of

grooves) and materials is carried out.

For this purpose we utilize the models

of metal-insulator-metal waveguide,

1D grating followed by a 3-D grating

configuration. Analysis of the mentioned

models reveals details of the filtering

capability of the radial polarization, i.e.,

transmission suppressing of TE and

supporting of TM modes correspondingly.

The electronic spectra of Bent carbon chains - ‘Particle-in-a-box’behavior

D. Zhao1, M. A. Haddad1, H. Linnartz,2,1

W. Ubachs1

1 VU University Amsterdam2 University of Leiden

Highly unsaturated hydrocarbon chain

species, both linear and nonlinear, play

an important role as precursors in the

formation of PAHs and fullerenes.

Electronic absorption spectra of three

non-linear carbon-chain radicals,

HC4CHC4H, HC4CHC6H, and

HC4C(C2H)C4H, have been recorded by

cavity ring-down spectroscopy through

an expanding hydrocarbon plasma. Their

molecular structures are unambiguously

determined from the electronic spectra

combined with deuterium labeling in

the gas phase. By comparing the results

to those of previously reported linear

chains, the general applicability of the

‘particle-in-a-box’ model and the poten-

tial of deuterium labeling in optical s

pectroscopic studies of bent carbon-chain

systems is discussed. This insight may

assist the characterization of electronic

transitions of other non-linear carbon

chains in future.

55

P61

Quantum optics with semiconductorspin ensembles

A.R. Onur1, A.U. Chaubal1, M. Sladkov1,

M.P. Bakker1, J. Sloot1, D. Reuter2, A. Wieck2,

C.H. van der Wal1

1 Zernike Institute for Advanced Materials,

University of Groningen,The Netherlands

2 Angewandte Festkörperphysik,

Ruhr-Universität Bochum, Germany

We present quantum optical studies with

ensembles of donor-bound electron

spins in ultra-pure GaAs materials with

Si doping at very low concentrations

(1013-1014 cm-3). These donor-bound

electrons (D0 systems) provide unique

system properties for solid state quantum

information processing, since they

combine a high level of ensemble homo-

geneity (as for atomic vapors) with

strong optical transitions and the ability

to nano-fabricate and integrate very

compact optoelectronic devices with

semiconductor processing tools.

Specifically, we report the observation

of dynamic nuclear polarization in

this material [1], using electromagneti-

cally induced transparency as a driving

mechanism and as a probe for the

effective magnetic, Overhauser, field.

[1] M. Sladkov et al., Phys. Rev. B 82, 121308

(2010).

56

Workgroups

AMSTERDAM (AMOLF)prof.dr. H.J. Bakker Ultrafast Spectroscopyprof.dr. L. Kuipers Nano-opticsprof.dr. A. Lagendijk Photon Scatteringprof.dr. A. Polman Photonic Materialsdr. J. Gómez Rivas* Nanowire Photonicsdr. F. Koenderink Resonant Nanophotonicsdr. G. Koenderink Soft Matter Imaging* High Tech Campus Eindhoven

AMSTERDAM (Universiteit van Amsterdam)prof.dr. T. Gregorkiewicz Opto-electronics Materialsdr. R.Sprik Soft matter physics waves in complex mediadr. N.J. van Druten Quantum Gases, Atom Optics, Quantum Informationdr. T.W. Hijmansprof.dr. H.B. van Linden van den Heuvellprof.dr. G.V. Shlyapnikovdr. R.J.C. Spreeuwprof. dr. J.T.M. Walraven

AMSTERDAM (Vrije Universiteit)prof.dr. W. Ubachs Frequency metrology and variation of fundamental Constants,dr. W. Vassen laser cooling and Bose-Einstein prof.dr. K.S.E. Eikema Condensation, high-intensity ultrafast lasers and dr. H.L. Bethlem x-Ray generation, spectroscopy of small molecules dr. S. Knoop (of atmospheric and astrophysical interest), dr. J.C.J. Koelemeij XUV Laser spectroscopyprof. dr. M.H.M. Janssen Ultrafast molecular photodynamics, photoelectron-Photoion

coincidence imaging, quantum state-to-State imaging of oriented molecules, quantum control and pulse shaping

prof.dr. J.F. de Boer Optical Coherence Tomography, spectroscopy

DELFT (Technische Universiteit)prof. dr.ir. J.J.M. Braat dr. A.J. L. Adamprof. Dr. P.C.M. Plankendr. S.F. Pereiradr. F. Bociortdr. N. Bhattacharyadr.ir. R. Hanson

Terahertz imaging & spectroscopy

Optical recording, near and far field microscopyOptical design, lithography

Optical aperture synthesisQuantum science in the solid state, quantum information, diamond defect centers

57

Workgroups

EINDHOVEN (Technische Universiteit)dr. ir. G.J.H. Brussaarddr. ir. S.J.J.M.F. Kokkelmansprof. dr. K.A.H. van Leeuwenprof. dr. ir. O.J. Luitendr. ir. P.H.A. Mutsaersdr. ir. E.J.D. Vredenbregt

ENSCHEDE (Universiteit Twente)prof. dr. K.J. Bollerdr. F.A. van Goordr. H. M. J. Bastiaensdr. P.J.M. van der Slot

Prof.dr. J.L. HerekDr. H.L. Offerhaus

prof. dr. V. Subramaniamdr. M.L Bennink prof.dr. Carl Figdor dr. H. Kanger dr. R. Kooyman dr. I. Segers-Nolten dr. W. Steenbergenprof. dr. A.J.G.M. (Ton) van Leeuwen dr. S. Manoharprof. dr. L.W.M.M. Terstappendr. C. Otto dr. R. Schasfoortprof. dr. W.L. Vosdr. A.P. MoskPepijn Pinkseprof. dr. M Pollnaudr. S. Garcia Blancodr. M. Hammerdr. H. Hoekstradr. R. De Ridderdr. K. Worhoff

Ultra cold plasma’s, Rydberg atoms, bright ion and electronbeams, atom optics, nanostructures by atom lithography,Compact (laser-driven) electron accelerators; generation of collective radiation (THz to XUV), including FEL physics;femtosecond-pulse physics, cold atomic interactions, quantum gases

Laserphysics and nonlinear optics, solid state. Parametricoscillators, laser wakefield acceleration. Nonlinear pulse propagation in photonic crystals. Frozen light, mid-IR molecular detection, high power diode lasers, laser materialprocessing.Biomolecular control, field shaping, coherent control,nonlinear/vibrational.Spectroscopy/microscopy, nanophotonics,plasmonic structures, near-field probe microscopy.Nano biophysics, genomic, proteomics, spectroscopy.

Biomedical photonic imaging, tissue imaging acoustic imaging and OCT.Medical cell biophysics, nonlinear spectroscopy and microscopy. Raman imaging Microfluidics.

Photonic crystals, scattering and localization

Applied NanophotonicsIntegrated optical microsystems

Workgroups

GRONINGEN (Kernfysisch Versneller Instituut)prof. dr. ir. R. Hoekstradr. T. Schlathölter

prof. dr. K. Jungmannprof. dr. H. Wilschutdr. L. Willmanndr. G. Onderwater

GRONINGEN (Rijksuniversiteit Groningen)prof. dr. ir. P.H.M. van Loosdrechtdr. M.S. Pchenichnikovprof. dr. J.Koesterdr. T. L.C. Jansendr. V.A. Malyshevdr. W.R. Browndr. G. Palasantzasprof. dr. B. Poolmanprof. dr. A. van Oijen prof. dr. ir. C.H. van der Walprof. dr. J.C. Hummelenprof. dr. M. A. Loi

LEIDEN (Universiteit Leiden)prof.dr. D. Bouwmeesterdr. M.J.A. de Dooddr. E.R. Elieldr. M.P. van Exterprof. G.W. 't Hooftprof. dr. J.P. Woerdmanprof. dr. G. Nienhuis (theory)prof. dr. E.J.J. Groenenprof. dr. S.L. Völkerprof. dr. M. Orritdr. P. Gastdr. M.I. Huberprof. dr. C.W.J. Beenakker (theory)prof. dr. G.J. Kroesdr. H.V.J. Linnartz

58

Radiation damage in biomolecular systems. Highly-charged ion physics, reaction microscopy, laser coolingand trapping, atomic processes at surfaces. Development of aX ray free electron laser ZFEL.Production of short-lived ions and atoms, ion/atom. Trapping, alkali/alkali earth trapping, atomic Spectroscopy,fundamental interactions, search for electric dipole moments.

Optical Condensed Matter Physics.Multidimensional femtosecond optical spectroscopy.Theory of Condensed Matter.

Molecular Systems and InterfacesNanoscale surface physics and Casimir forcesMembrane EnzymologySingle-Molecule Biophysics.Physics of Quantum Devices.Organic photovoltaicsPhotophysics and OptoElectronics Organic Semiconductor

Quantum entanglement, macroscopic entanglement, semiconductor quantum physics (spintronics), spatial coherence, photonic crystals, sub-wavelength optics,plasmonics

Optical traps, light forces, quantum information Single-molecule physics, Electron Paramagnetic Resonance,Spectral hole burning.

Mesoscopic physics, graphene, topological quantum effectsQuantum chemistry, Atmospheric physics.Laboratory astrophysics

59

Workgroups

NIEUWEGEIN (FOM Instituut voor Plasmafysica RIJNHUIZEN)dr. A.F.G. van der Meerdr. G. Berdendr. B. Redlichprof.dr. J. Oomensdr. J.M. Bakkerdr. A.M. Rijs

NIJMEGEN (Radboud Universiteit Nijmegen)prof. dr. D.H. Parkerdr. F.J.M. Harren

dr. S.Y.T. van de Meerakkerprof. dr. Th. Rasing

dr.ir. G.C. Groenenboomdr. H.M. Cuppendr. K. Gubbels prof. dr.ir. A. van der Avoird (theory)prof. dr. W.J. van der Zandeprof. dr. W.L. Meertsdr. R.T. Jongma

UTRECHT (Universiteit Utrecht)prof. dr. P. van der Stratendr. ir. J.M. Vogelsdr. D. van Oostenprof.dr.ir. H.T.C. Stoof

dr. R.A. Duine

FEL physics, generation and application of infrared/THz radiation.

Molecular physics. infrared ion spectroscopy and structure,conformation selective spectroscopy, mass spectrometry, biomolecules, metal clusters, astrochemistry.

Laser physics, molecular photodissociation, atmosheric processes, trace gas detection, medical and biological applications.Cold and controlled collisionsNonlinear optics, time-resolved laser spectroscopy, light scattering, magnetic, polymeric and liquid crystallinematerials, atom lithography.Molecular interactions and light-induced processes.Mobility in solid molecular materials

Biomolecular structure, Molecular and atmospheric Physics,THz generation, detection and applications to biomoleculesand bio-mimetics, Free Electron Laser.

Laser manipulation of atoms, Bose-Einstein condensation,Atom optics.Cold atom nanophotonics.Dynamics of Bose-Einstein Condensates, Quantum Effects inDegenerate Fermion and/or Boson gases.Spintronics.

35th meeting of the section atomic molecular and optical ... · this meeting is organized under the...

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