Swinburne University of TechnologyMelbourne, Australia

Centre for Atom Optics and Ultrafast Spectroscopy

Research Report 2001

PREFACE 3

CONTACT INFORMATION 4

ATOM OPTICS 5

Magnetic Optical Elements for Ultracold Atoms 5

Integrated Atom Optics 6

Ultracold Molecules 7

Light Propagation in Steeply Dispersive Atomic Media 7

ULTRAFAST LASER SPECTROSCOPY 8

Femtosecond Photon Echoes 8

– Biological Molecules 8

– Spectrally Resolved Photon Echoes 9

– Semiconductor Quantum Dots 9

Femtosecond Ramsey Interferometry 10

Femtosecond Laser Ablation 10

– Micromachining of Polymers 11

– Micromachining of Semiconductor Gallium Nitride Films 11

– Femtodentistry 11

QUANTUM INFORMATION 12

Decoherence in Quantum Computation 12

Quantum Adiabatic Computation 12

Quantum Measurement 12

PUBLICATIONS 13

CONFERENCES 15

SEMINARS 17

MEDIA PRESENTATIONS 17

COMPETITIVE GRANTS 18

COLLABORATIONS 18

VISITING POSITIONS, HONOURS AND AWARDS 19

CONTENTS

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The Swinburne Centre for Ultrafast Laser Spectroscopy(SCULS) was opened on 26 February 1999 by ProfessorAhmed Zewail, 1999 Chemistry Nobel Laureate, as part ofthe new Swinburne Optics and Laser Laboratory (SOLL)complex. The Centre, which is funded by a SwinburneStrategic Initiative Grant, initially comprised a state-of-the-artFemtosecond Laser Facility housed in a new purpose-builtlaboratory and two personnel, Martin Lowe and myself, bothseconded on a part-time basis from CSIRO. Later that yearwe were joined by PhD student Craig Lincoln, Dr JeremyBolger from Redstone Australia Mining and Dr WayneRowlands from Yale University.

In February 2001 the Atom Optics Group at CSIRO,comprising Dr Russell McLean, Dr Andrei Sidorov, DavidGough and myself, moved to Swinburne University to join theSCULS group, to form the Centre for Atom Optics andUltrafast Spectroscopy (CAOUS). We are most grateful toSwinburne University for start-up funding to establish thenew Atom Optics laboratory and to CSIRO for allowing us tobring the laser and optics equipment with us. In 2001 wewere also joined by Dr Tien Kieu from CSIRO to initiateresearch in quantum information, Dr Lap Van Dao from theUniversity of NSW to work on ultrafast spectroscopy, and twonew PhD students, Heath Kitson and Falk Scharnberg. Wewere fortunate to also gain the part-time services of twoadjunct professors, Professor Alan Head from CSIRO andProfessor Geoffrey Opat from the University of Melbourne.In 2002 we welcomed two new researchers, AssociateProfessor Bryan Dalton from the University of Queenslandand Dr Barbara McKinnon from Monash University.

This Report covers the first three years’ activities ofCAOUS/SCULS, from 1999 to 2001. The primary objective ofthe Centre is to carry out fundamental and strategic researchin the areas of Atom Optics, Ultrafast Spectroscopy, andQuantum Information. These three areas are among thetopics listed in the Federal Government’s recently designatedpriority research area of Photon Science and Technology. InAtom Optics, we are developing high-quality atomic opticalelements, including mirrors, beamsplitters, surfacewaveguides and surface microtraps, for manipulating beamsof ultracold laser-cooled atoms, and we are using laser-cooled atoms to generate samples of ultracold molecules.We have recently observed near-specular reflection of acloud of ultracold rubidium atoms dropped onto magneticmicrostructures with periodicities of around a micron. InUltrafast Laser Spectroscopy, we are developingfemtosecond coherent nonlinear techniques, includingstimulated photon echoes, transient grating and Ramseyinterference techniques, to investigate ultrafast processes incomplex molecular systems, including biological molecules,dye molecules and semiconductor quantum dots, on timescales down to less than 10-13 s. We have successfully usedfemtosecond three-pulse photon echo techniques toinvestigate the photodissociation of the biologically important

molecule, carbonmonoxy myoglobin. We have also appliedfemtosecond Ramsey interference techniques to ‘observe’the full cycle of an optical transition in rubidium as it evolvesin time with a period of about 2 femtoseconds. In QuantumInformation, Tien Kieu has proposed a quantum computation‘algorithm’ for one of the insoluble problems of mathematics,the Hilbert’s tenth problem, which is ultimately linked to thehalting problem for Turing machines. A number of papersresulting from this work are currently attracting world-wideattention.

Details of the research activities of CAOUS are presented insubsequent sections. It is rewarding to see a steady streamof publications already flowing from our research and thework being reported at the major international conferences.At the recent Australasian Conference on Optics, Lasers andSpectroscopy in Brisbane, the group contributed six oral andfive poster presentations. In 2003 we will be co-hosting the16th International Conference on Laser Spectroscopy, whichis the premier forum for the announcement of new world-wide developments in laser spectroscopy and related fields.

In the 2002 round of ARC grants, CAOUS was successful insecuring two Discovery Grants, a Linkage InfrastructureGrant (with the University of WA and Macquarie University),and a Research Development Grant. We were also awarded a$1.98M Systemic Infrastructure Initiative grant (with theSwinburne CIAO, CMP and IRIS groups and RMIT University)from the Federal Government to establish an IntegratedMicrofabrication Facility. These grants are in addition to aResearch Infrastructure Equipment and Facilities (RIEF) grant(with the University of Melbourne and the Swinburne CMP) in2001.

I wish to take this opportunity to thank the various membersof CAOUS for their efforts in getting the new laboratories upand running so quickly, and especially Dr Jeremy Bolger forspending a year with us helping to establish thefemtosecond laser laboratory. We particularly wish to thankthe Vice-Chancellor, Professor Iain Wallace, the Pro Vice-Chancellor (Research), Professor Kerry Pratt, and the Head ofthe School of Biophysical Sciences and ElectricalEngineering, Professor David Booth, for their continuedsupport and encouragement.

Shortly before this Report went to press, we were shockedand deeply saddened to learn of the sudden and prematuredeath of our friend and colleague, Professor Geoffrey OpatAO FAA, collaborator of the Atom Optics group since 1991and Adjunct Professor of this university since 2001. Geoffhad a profound influence on the lives, scientific careers andresearch work of many of us and will be greatly missed.

Peter Hannaford, Director of CAOUS March, 2002

PREFACE

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CONTACT INFORMATION

Centre for Atom Optics and Ultrafast Spectroscopy (CAOUS)

School of Biophysical Sciences and Electrical EngineeringSwinburne University of TechnologyPO Box 218 Hawthorn Victoria Australia 3122

Phone +61 (0)3 9214 5164 (Peter Hannaford)Fax +61 (0)3 9214 5840Website http://www.swin.edu.au/lasers/caous

StaffProf Peter Hannaford (Director)phannaford@swin.edu.au Ext 5164

A/Prof Bryan Daltonbdalton@swin.edu.au Ext 8187

Dr Lap Van Daodvlap@swin.edu.au Ext 4317

Mr David Gough dgough@swin.edu.au Ext 4308

Prof Tien Kieu kieu@swin.edu.au Ext 8026

Mr Martin Lowemlowe@swin.edu.au Ext 4309

Dr Barbara McKinnonbmckinnon@swin.edu.au Ext 8187

Prof Russell McLeanrmclean@swin.edu.au Ext 8555

Dr Wayne Rowlandswrowlands@swin.edu.au Ext 8142

Prof Andrei Sidorovasidorov@swin.edu.au Ext 5848

Dr Jeremy Bolger (finished 2000)

Mr Peter Larkins (finished 2000)

PhD studentsHeath Kitson hkitson@swin.edu.au Ext 5680

Craig Lincolnclincoln@swin.edu.au Ext 5680

Falk Scharnberg fscharnberg@swin.edu.au Ext 5680

Xiaoming Wen (to start 2002)

Adjunct professorsProf Alan Head AO FAA FRS (CSIRO Manufacturing Scienceand Technology)

Prof Geoffrey Opat AO FAA (The University of Melbourne)

Research AssociatesDr Alexander Akulshin(The University of Melbourne)

Dr Tim Davis (CSIRO Manufacturing Science and Technology)

Dr Khai Vu

Dr Margaret Wong (School of Engineering and Science, Swinburne University)

Undergraduate studentsShannon Whitlock Honours student in Optronics and Lasers (2002)

Jack ManningEngineering and Science R&D student (2002)

Pascal Rouviere Internship student from Paris (to start 2002)

Adam DellerEngineering and Science R&D student (finished 2001)

Christoph Rill Exchange student from Vienna (finished 2001)

Lee Manuele Work experience student (finished 2001)

Ivan Blajer Summer vacation student (finished 2001)

Christine Aussibal Internship student from Paris (finished 2000)

Mara GiovannettiFinal Year Chemistry student (finished 2000)

Joshua Pearce Engineering and Science R&D student (finished 2000)

Trent Boyce Engineering and Science R&D student (finished 1999)

How to find usThe Centre for Atom Optics and Ultrafast Spectroscopy ishoused in a modern, purpose-built laboratory complex, theSwinburne Optics and Laser Laboratories, on the groundfloor of the Applied Sciences building, at SwinburneUniversity’s Hawthorn Campus, 7 kms from the heart ofMelbourne (Melways Directory, map 45, grid reference E-10). The entrance to CAOUS is in Serpells Lane, offBurwood Road, and next to Glenferrie Station, which is wellserved by trains on the Lilydale, Belgrave and Alamein lines.For parking we advise a nearby multi-storey car park inWakefield Street, off Glenferrie Road.

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Atom Optics Laser light may now be used to cool a cloud of atoms towithin a few microkelvin of absolute zero, where the atomsbehave like waves, with de Broglie wavelengths comparableto the wavelength of light. This has opened up a new field ofoptics, ‘Atom Optics’, in which beams of slowly movingatoms can be reflected, diffracted and made to interfere inmuch the same way as beams of light. Interferometersbased on beams of slowly moving atoms can be extremelysensitive to quantities such as gravity fields and theirgradients, accelerations and rotations of the reference frame.

CAOUS has two large Atom Optics laboratories which housethree laser-cooling and trapping set-ups, a single-modetitanium sapphire laser (Coherent 899) pumped by a 10 W Millennia Nd:YVO4 laser, a single-mode ring dye laser(Spectra-Physics 380D), a 50 W CO2 laser (Deos GEM-50),three Tui Optics single-mode diode lasers, and two PrincetonInstruments CCD cameras. We are currently establishing amicrofabrication laboratory comprising a semi-clean roomwith a thin-film deposition system, a photolithography maskaligner, an optical confocal scanning microscope profilometer,and an atomic force/magnetic force microscope.

Magnetic Optical Elements for Ultracold Atoms Russell McLean, Andrei Sidorov, David Gough,Peter Hannaford (CAOUS), Alexander Akulshin, Geoffrey Opat (University of Melbourne), Brett Sexton, Tim Davis (CSIRO)

To exploit the potential of Atom Optics, high-quality atomicoptical elements including mirrors and beamsplitters areneeded. A novel approach, which we developed while atCSIRO, is based on the interaction between the magneticmoment of the atom and the exponentially decayingmagnetic field above a periodic array of magnetic elements,where the decay length is determined by the periodicity ofthe array (Fig. 1a) [1, 2]. A magnetic mirror consisting of aperiodic array of magnets may be converted into a magneticdiffraction grating, or diffractive beamsplitter, for slowlymoving atoms by applying a small bias magnetic fieldperpendicular to the surface [1].

Figure 1b Magnetic field distribution above a periodic groovedmagnetic structure.

To produce a ‘hard’ magnetic mirror with small decay lengthand to be able to use the magnetic structures as diffractivebeamsplitters, the periodicity of the structure needs to besmall, preferably about a micron. Generating sufficientlystrong and uniform magnetic fields above such finestructures has proven to be a challenge, but we haverecently succeeded in producing very promising, micron-period magnetic mirrors based on grooved, perpendicularlymagnetised CoCr structures [3] (Fig. 1b). These structuresare fabricated using electron-beam lithography to write agrooved pattern in photoresist, from which a nickel master isreplicated. This in turn is used to replicate a grooved non-magnetic substrate coated with a film of magnetic Co0.8Cr0.2.Grooved CoCr magnetic structures with periodicities rangingfrom 0.7 to 4 µm have been successfully fabricated andcharacterised using atomic and magnetic force microscopy.

The magnetic mirrors have been tested by dropping a cloudof laser-cooled rubidium or caesium atoms onto the surfaceand recording laser-induced fluorescence signals from theatom cloud in a CCD camera (Fig. 2, overleaf). Measurementsof the atom cloud at various times before and after reflectionreveal that the reflection is predominantly specular, with anangular spread of less than about 10 mradians introduced byimperfections in the mirror [3]. The accuracy of thespecularity measurements is presently limited by residualcurvature in the magnetic mirror introduced duringfabrication and by the method of analysis.

This grooved type of magnetic structure appears to be themost promising to date for producing high-quality magneticmirrors for ultracold atoms. It should be possible to improvethe quality further by using TbGdFeCo films, which can haveexcellent magnetic homogeneity and higher remanentmagnetic fields than CoCr.

1. G.I. Opat, S.J. Wark and A. Cimmino, Appl. Phys. B 54, 396 (1992)

2. A.I. Sidorov, R.J. McLean, W.J. Rowlands, D.C. Lau, J.E. Murphy, M.Walkiewicz, G.I. Opat and P. Hannaford, Quantum Semiclass. Opt. 8,713 (1996)

3. A.I. Sidorov, R.J. McLean, B.A. Sexton, D.S. Gough, T.J. Davis, A.Akulshin, G.I. Opat and P. Hannaford, Comptes Rendus 2, Series IV,565 (2001)

ATOM OPTICS

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N N NS S S

NS

NS

5

Figure 1a Magnetic field distribution above a periodic array ofmagnets of alternating polarity. Atoms in positivemagnetic states (mgF>0) are repelled by the increasingmagnetic field strength above the array.

atom (mgF>0)

a

ATOM OPTICS

Figure 2 Side view of the laser-induced fluorescence from a cloudof about one million ultracold rubidium atoms falling ontoand bouncing from a grooved magnetic microstructure ofperiodicity 2 µm. Times after release of the atoms fromthe laser-cooling optical molasses are shown.

Integrated Atom Optics Falk Scharnberg, Andrei Sidorov, Russell McLean,David Gough, Peter Hannaford (CAOUS), Geoffrey Opat (University of Melbourne), Tim Davis (CSIRO)

Advances in lithography and microfabrication techniqueshave recently led to the development of miniature surface-based current-carrying optical elements for manipulatingultracold atoms, allowing the construction of networks ofmicrotraps, waveguides, beamsplitters and couplers on thesurface of a substrate [1] – ‘integrated atom optics’. Scalingdown the dimensions of the optical elements has theadvantage of allowing large magnetic field gradients andvery tight confinement of the atoms at moderate electriccurrents. The tight confinement in a magnetic microtrapincreases the vibrational quantum level splitting, allowing thesplitting to exceed the photon recoil energy (Lamb-Dickeregime). This also increases the elastic collision rate betweenthe ultracold atoms, thereby reducing the time to reachquantum degeneracy (Bose-Einstein condensation).

We are investigating the use of permanent magnetic films(CoCr or TbGdFeCo) with perpendicular magnetisation toconstruct surface-based microscopic magnetic traps,waveguides and beamsplitters for ultracold atoms [2],including Bose-Einstein condensates, with the objective ofdeveloping a integrated surface-based atom interferometer.A single magnetic strip or two separated magnetic strips, forexample, can produce a two-dimensional quadrupolepotential to form a microscopic waveguide for thepropagation of atomic de Broglie waves (Fig. 3). Acombination of magnetic strips and current-carrying wireloops can produce a surface microtrap that can be coupledto a standard magneto-optical trap.

Permanent magnets have potential advantages over current-carrying conductors for generating microscopic magneticfield structures. In particular thin-film magnetic structurescan produce large magnetic field gradients (~107 G/cm)without the risk of excessive heating and potentialbreakdown of the current-carrying circuits. Use of permanentmagnets also overcomes problems due to current variations,imperfect insulation between conductors, and open and shortcircuits.

1. J. Reichel, W. Hänsel and T.W. Hänsch, Phys. Rev. Lett. 83, 3398(1999)

2. T.J. Davis, J. Opt. B: Quantum Semiclass. Opt. 1, 408 (1999)

Figure 3 Atom waveguides produced by a 2D quadrupole potentialabove (a) a single permanent magnetic strip with biasmagnetic field, and (b) two separated permanentmagnetic strips.

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(a)

(b)

Ultracold Molecules Heath Kitson, Wayne Rowlands

Two major advances in precision molecular spectroscopy inrecent years have been the application of laser cooling andtrapping techniques to molecules [1] and the application ofultrafast laser spectroscopic techniques to studies ofmolecular dynamics in real time (‘femtochemistry’) [2]. Thisproject aims to combine these two technologies to extendfemtochemistry into the domain of ultracold atoms andmolecules.

Several techniques exist for the generation of ultracold (T < 1 mK) molecules. The approach we are taking is toproduce molecules by the photoassociation (‘light-assisted’collisions) of laser-cooled atoms. The initial work involves theformation of ultracold diatomic rubidium molecules, Rb2.There is much interest in optimising the production ofultracold molecules, and particularly in having control overthe population of the vibrational and rotational molecularstates.

The laser-cooling set-up that will be used to generatesamples of ultracold molecules is shown in Fig. 4. Thephotoassociated molecules will be captured in a far-offresonant optical dipole trap, based on a tightly focussedinfrared beam from a 50 W CO2 laser. Such an optical traphas a large detuning from all relevant atomic and moleculartransitions, and thus long storage times are possible. Theinitial program is to use the trapped ensemble of ultracoldmolecules for spectroscopic studies. However, there are alsoother possible applications, such as further cooling of theensemble to the transition point for molecular Bose-Einsteincondensation.

Femtochemistry has previously permitted studies offundamental chemical processes in real-time [2], such as thedependence of reaction rates upon temperature (Arrhenius’sscaling law). We will be able to test the validity of these lawsat temperatures very close to absolute zero, where quantummechanical effects dominate.

1. See, e.g., J.T. Barnes, P.L. Gould and W.C. Swalley, Adv. At. Mol. Opt.Phys. 42, 171 (2000).

2. See, e.g., A.H. Zewail, J. Phys. Chem. A 104, 5660 (2000),and references therein.

Light Propagation in Steeply Dispersive Atomic Media

Alexander Akulshin, Alberto Cimmino, Geoffrey Opat(University of Melbourne), Andrei Sidorov, Russell McLean,Jack Manning, Peter Hannaford (CAOUS).

Light-induced coherence between ground-state magneticsublevels may cause extremely large enhancements of thedispersion and nonlinear susceptibility of alkali atomicvapours. Depending upon the parameters of the opticaltransition, the coherent superposition of sublevels may beeither ‘dark’, producing electromagnetically inducedtransparency, or ‘bright’, producing electromagneticallyinduced absorption [1]. An atomic gas prepared in a darkcoherent state exhibits a very steep positive dispersion,allowing light propagation with ultra-slow group velocity.In a bright state the dispersion is also steep but negative [2],leading to the counterintuitive situation of a negative groupvelocity in which the peak of a light pulse exits the atomicmedium before it goes in [3].

We are extending these investigations on bright and darkatomic states to samples of ultracold laser-cooled rubidiumatoms to reduce the interaction times of the atoms andhence to increase the steepness of the dispersion of theatomic medium. The ability to slow and store light haspotential applications in quantum information processing.

1. A. Lezama, S. Barreiro and A.M. Akulshin, Phys. Rev. 59, 4996 (1999)

2. A.M. Akulshin, S. Barreiro and A. Lezama, Phys. Rev. Lett. 83, 4277(1999)

3. A.M. Akulshin and G.I. Opat, Aust. Opt. Soc. News 15, 30 (2001)

ATOM OPTICS

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Figure 4 Heath Kitson tweaking the laser-cooling set-up to beused for generating samples of ultracold molecules.

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Ultrafast Laser SpectroscopyThe Swinburne Femtosecond Laser Facility is used in a widerange of applications involving ultrafast phenomena inphysics, chemistry, biology and engineering. The Facility(shown in Fig. 5) is a Spectra-Physics system comprising aTsunami mode-locked titanium sapphire laser pumped by a5 W Millennia Nd:YVO4 laser; a Spitfire regenerativeamplifier; and two independently tunable optical parametricamplifiers, with capabilities of second and fourth harmonicgeneration and sum frequency mixing of the signal and idlerbeams. The system produces pulses of duration down to 50fs, pulse energies up to about 1 mJ (allowing peakintensities up to about 1015 W cm-2), and wavelengthscovering the range 250-2500 nm. Other major equipmentincludes a 20 cm optical delay line with step size down to 25 nm (0.2 fs), a molecular beam system, a femtosecondstreak camera (Hamamatsu C5680), and an ultrafast gatedintensified CCD imaging system (LaVision PicoStar HR).

Figure 5 Craig Lincoln during a late-night run on the SwinburneFemtosecond Laser.

Femtosecond Photon Echoes The use of femtosecond coherent nonlinear techniques suchas stimulated photon echoes provides a powerful method forinvestigating ultrafast transient processes, including energytransfer, charge transfer and laser-induced vibrationalcoherences, in complex molecular systems such asbiological molecules, dye molecules and semiconductors ontime scales down to the order of the vibrational period of amolecule (~10-13 s).

We are using a three-pulse photon echo technique, in whichtwo excitation pulses and a third (probe) pulse withwavevectors k1, k2 and k3 (where k=2π/λ in the direction ofpropagation) and temporal separations t12=τ and t23=Tpropagate through the sample (Fig. 6a). The sum of theelectric fields emitted by different molecules having a spreadof frequencies (inhomogeneous broadening) vanishes in alldirections except the ‘phase-matching’ directions,e.g., k4,5 = k3 ± (k1 – k2), along which the fields rephase attimes near τ after the third pulse, giving rise to an ‘echo’signal. The echo signal is recorded by scanning either the‘coherence’ time τ or the ‘population’ time T. The additionaldegree of freedom allowed by having a third pulse in athree-pulse experiment enables one to extract the opticaldephasing time T2 (homogeneous broadening) of the

transition, the population relaxation time T1 of the upperlevel, and the inhomogeneous broadening, which may arise,for example, from the fluctuating environment of surroundingmolecules. Furthermore, when the probe has a wavelengthdifferent from that of the pump pulses, it can systematicallyprobe the population and coherences of excited levels ortransient species at different internuclear separation as theexcited molecule evolves on a femtosecond time scale. In thespecial case of coincident pump pulses (τ=0) themeasurement becomes a transient grating (or transient four-wave mixing) experiment. Figure 6b shows three-pulse two-colour photon echo signals k4,5 = k3 ± (k1 – k2) for the dyemolecule, Rhodamine B (RhB) in methanol solution. Alsoevident are some weak high (fifth) order photon echoes k6,7 = k3 ± 2 (k1 – k2), corresponding to two-photonprocesses, as well as the two-pulse photon echo signals 2k1 – k2, 2k2 – k1, etc.

In order to interpret and analyse the multiple-pulse photonecho data, theoretical models involving the determination ofhigh-order polarisations with multiple-time correlationfunctions are being developed.

Figure 6a Three-pulse photon echo experiment.

Figure 6b Three-pulse, two-colour (580, 610 nm) photon echoes (k4, k5) for Rhodamine B in methanol (see text).

Biological Molecules Craig Lincoln, Lap Van Dao, Martin Lowe, Wayne Rowlands,Shannon Whitlock, Barbara McKinnon, Peter Hannaford

We are investigating ultrafast transient processes inbiologically important molecules, including thephotodissociation of carbonmonoxy myoglobin (MbCO) intoMb and CO. Myoglobin is the single heme analogue of themore complex haemoglobin and is responsible for thestorage of oxygen in animals and plants.

We use the transient grating technique in combination with athree-pulse photon-echo peak shift (3PEPS) technique, inwhich the shift (∆τ) in peak temporal position of the twoecho signals k4 and k5 is recorded as a function ofpopulation time T. The transient grating signals provide

ULTRAFAST LASER SPECTROSCOPY

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ULTRAFAST LASER SPECTROSCOPY

information on the population dynamics, while the 3PEPSsignals provide information on the inhomogeneousbroadening and laser-induced coherences essentially in theabsence of population effects. The transient grating signal forMbCO (Fig. 7a) can be analysed into three components,having decay times of about 270 fs, 3 ps and >200 ps,which are similar to the decay times associated with therecently proposed three stages of photodissociation of therelated molecule, carbonmonoxy haemoglobin [1]. There isalso evidence of oscillations, which are associated with laser-induced vibrational coherences in the electronic ground levels.

The three-pulse photon echo signals for MbCO showsignificant peak shifts, indicating strong inhomogeneousbroadening. The 3PEPS curve (Fig. 7b) consists of an initialrapidly decaying component (<100 fs) resulting fromdestructive interference of coupled vibrational wavepackets,followed by a slowly decaying oscillatory component whichis associated with vibrational coherences in electronicexcited states [2].

Figure 7 (a) One-colour (515 nm) transient grating and (b) one-colour three-pulse photon echo peak shift signals for carbonmonoxy myoglobin.

1. S. Franzen, L. Kiger, C. Poyart and J-L. Martin, Biophys. J. 80, 2372(2001)

2. C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and P. Hannaford,Femtochemistry V (World Scientific, in press)

Spectrally Resolved Photon Echoes Lap Van Dao, Craig Lincoln, Martin Lowe, Barbara McKinnon,Peter Hannaford

We are exploring the use of spectrally-resolved three-pulse,two-colour stimulated photon echo techniques, in which thewavelengths of the echo signals are analysed in aspectrometer, allowing the population and dephasingcomponents of the echo signal to be separated. Figure 8shows spectra of the photon echo signal recorded for arange of population times T (with τ=0) for RhB in methanol,where the wavelengths of the pump and probe beams are520 nm and 640 nm, respectively [1]. A strong dependenceof the photon-echo signal on the population time T and alsoon the wavelength of the pump pulse is observed. At shortpopulation times T new bands appear at wavelengths around610 and 625 nm. The inset to Fig. 8 shows the evolution ofthe (normalised) echo intensity as a function of populationtime T for the detection wavelengths 610, 625 and 640 nm.

The strong component at the central probe wavelength (640 nm), which represents a population grating signalcreated by the two interacting pump pulses, has a very slowdecay (> 10 ps) corresponding to relaxation of the gratingcaused, for example, by intramolecular energy and chargetransfer, while the weak component at 610 nm, whichrepresents a ‘pure’ echo signal, has a rapid decay (400 fs)due to dephasing of the optical transition. The rise times ofthe echo signals at different detection wavelengths allow adetermination of the relaxation times (80-200 fs) for theinitially excited vibrational level to lower vibrational levels inthe excited state.

Figure 8 Spectrally resolved three-pulse, two-colour (520, 640 nm)photon echo signals for RhB in methanol for differentpopulation times A: 110 fs, B: 300 fs, C: 350 fs, D: 400 fs,E: 450 fs. Inset: time evolution of echo intensity for threedetection wavelengths 1: 610 nm, 2: 625 nm, 3: 640 nm.

1. L.V. Dao, C.N. Lincoln, R.M. Lowe and P. Hannaford, submitted toPhysica B

Semiconductor Quantum DotsLap Van Dao, Martin Lowe, Peter Hannaford (CAOUS)Hisao Makino, Takafumi Yao (Tohoku University, Japan)

Semiconductor quantum dots in which the dot size iscomparable to the exciton radii have unique electronicproperties due to the effect of the three-dimensionalconfinement. We are using femtosecond three-pulse two-colour photon echo and population grating techniques tocharacterise cadmium telluride quantum dots grown on zincselenide by molecular beam epitaxy [1]. The time evolutionof the population grating signal shows a fast decay (2-3 ps),corresponding to migration and tunnelling of the exciton toneighbouring quantum dots, followed by a slower decay (20 ps to >100 ps) which is related to the lifetime of theexciton.

The peak intensity of the three-pulse photon echo signalsversus population time T recorded at detection wavelengthslonger than the excitation wavelength (Fig. 9, overleaf)exhibits a slowly decaying oscillatory quantum beatcomponent. The measured optical dephasing timescorrespond to homogeneous linewidths of 0.8-1.2 meV whilethe period of the oscillation corresponds to an excitonbinding energy of about 13 meV. The dependence of thesequantities on the detection wavelength is associated with thedifference in sizes of the quantum dots.

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Figure 9 Three-pulse, two-colour (515, 530 nm) photon echosignal for CdTe quantum dots grown on ZnSe, recordedat detection wavelengths of 515 nm ( ), 525 nm ( ),and 535 nm ().

1. L.V. Dao, R.M. Lowe, P. Hannaford, H. Makino and T. Yao, submitted toAppl. Phys. Lett.

Femtosecond Ramsey Interferometry Martin Lowe, Lap Van Dao,Wayne Rowlands, Peter Hannaford

We are applying Ramsey’s separated oscillatory fieldstechnique [1], commonly used in the microwave frequencyregime, to the optical frequency regime, using pairs oftemporally-separated, phase-coherent femtosecond laserpulses [2]. The first pulse generates optical coherencebetween the excited and ground states of the atom (ormolecule), inducing an oscillating optical dipole thatcontinues to evolve freely in time decaying with acharacteristic dephasing time. The second (delayed) pulseinterrogates the oscillating optical dipole, leading tointerference fringes in the detected fluorescence with aperiod corresponding to that of the optical transition. In thisway it is possible to observe the full cycle of an opticaltransition in real time as it actually evolves at opticalfrequencies of about 1015 Hz.

Femtosecond Ramsey interference techniques provide apowerful high-resolution method that is yet to be exploited.The resolution is determined essentially by the time-delaybetween the two phase-coherent pulses, and is not limitedby the broad spectral bandwidth (~15 nm) of thefemtosecond pulses. The Ramsey inference fringes containessentially all the spectroscopic information about thetransition, including the fine and hyperfine structure of theupper and lower levels, the rotational and vibrationalstructure of the levels (in the case of molecules), thedephasing time of the optical dipole, and the absolutefrequency of the transition, which can be determined bydirectly counting the optical cycles.

Figure 10b shows Ramsey interference fringes recorded forthe rubidium D1,2 lines using an excitation wavelength of 787 nm. The phase-coherent pulses are generated in aMichelson interferometer, which has a 20 cm variable delayline (1.3 ns) and step size down to 25 nm (0.2 fs) (Fig. 10a).Strong beat signals are observed at a period of 2.6 fs (insetto Fig. 10b), corresponding to the frequency of the opticaltransition (4x1014 Hz), and at 140 fs (Fig. 10b), correspondingto the fine-structure splitting 52P3/2 – 52P1/2 (7x1012 Hz).

Figure 10 (a) Femtosecond Ramsey interference arrangement.

Figure 10 (b) Femtosecond Ramsey fringes for the Rb D1,2 lines.The 2.6 fs beat (in inset) corresponds to the opticalfrequency (4x1014 Hz) and the 140 fs beat to the fine-structure splitting.

1. N.F. Ramsey, Molecular Beams, Oxford Univ. Press (1956)

2. M. Bellini, A. Bartoli and T.W. Hänsch, Opt. Lett. 22, 540 (1997)

Femtosecond Laser Ablation In conventional pulsed laser ablation, for example, usingnanosecond pulses from an excimer or Nd:YAG laser, theablation mechanism is thermally driven, which can limit theprecision of the micromachining, and the walls of amachined hole often taper with increasing depth, limitingachievable aspect ratios to about unity.

In the case of femtosecond laser ablation the duration of thepulse is short compared with the thermal conduction timeand the characteristic relaxation times in the solid, andconventional thermal ablation is prohibited. In this case laserablation is believed to proceed via a non-thermalelectrostatic mechanism [1]. At the typical peak laserintensities available from a femtosecond regenerativeamplifier (1013-1015 W cm-2) the laser energy absorbed by anelectron through multi-photon processes exceeds theionisation potential and the energy required for the electronto escape the target, and the charge separation of theenergetic electron and the parent ion creates a huge electricfield which removes the ions one by one, thereby allowinghigh precision ‘non thermal’ micromachining.

1. E.G. Gamaly, A.V. Rode, B. Luther-Davies and V.T. Tikhonchuk,Physics of Plasmas 9, 949 (2002)

ULTRAFAST LASER SPECTROSCOPY

1111

ULTRAFAST LASER SPECTROSCOPY

Micromachining of Polymers Martin Lowe, Peter Hannaford (CAOUS)Erol Harvey (Industrial Research Institute Swinburne)Yanping Zhang, Akira Endo (Sumitomo Heavy Industries, Japan)

We are investigating femtosecond laser ablation of variouspolymers, including PMMA, PTFE and Polycarbonate, using100 fs laser pulses at 800 nm and pulse energies up toabout 1 mJ. For beams focussed by a plano-convex lens,high-quality, high aspect-ratio (>10) micromachining of holeswith diameters of 20-40 µm and depths of 300-400 µm hasbeen achieved (Fig. 11a) [1]. It appears that the hole formedby the initial laser pulses acts as a fibre to couple the beamof subsequent pulses into the bottom of the hole andpropagate the machining, thereby leading to holes with highaspect ratio.

Figure 11 (a) Micromachined hole with high-aspect ratio in PMMAusing femtosecond laser ablation.

Figure 11 (b) Array of microstrings formed in PMMA when usingprojection patterning with a rectangular pinhole.

When using projection patterning with a rectangular pinhole,regular arrays of micro-strings with diameters as small as 2 µm and lengths greater than 10 mm are observed deepwithin the bulk of the sample (Fig. 11b). This phenomenon isattributed to effects of diffraction of the spatially coherentfemtosecond laser beam by the rectangular hole andphotopolymerisation by the diffracted self-focussing beamswithin the polymer sample.

1. Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo, Appl.Surface Sci. 186, 345 (2002)

Micromachining of Semiconductor Gallium Nitride Films Lap Van Dao, Martin Lowe

Semiconductor films based on III-V nitrides, particularly GaN,are becoming increasingly important for the production ofnew-generation blue diode lasers and blue light emittingdiodes. Gallium nitride resists wet chemical etchants, andother methods need to be developed for machining thedesired structures. Laser ablation, in principle, offers a directand versatile means of surface modification without the needfor chemical processes. However, attempts to ablate GaNwith nanosecond pulses from Nd:YAG or excimer lasers haveresulted in a layer of gallium being formed on the surface,due to thermal decomposition during the laser pulse. We areinvestigating the ablation of thin GaN films using 100 fspulses at 800 nm. For fluences around 0.3 J cm-2 and pulserepetition rates of 1 kHz, regular channels of depth ≤1 µmhave been successfully machined into GaN films on sapphiresubstrates.

FemtodentistryAndrei Rode, Eugene Gamaly, Barry Luther-Davies (Australian National University) Bronwyn Taylor, Judith Dawes (Macquarie University, Sydney)Ambrose Chan (Private Dental Practice, Caringbah, NSW )Martin Lowe, Peter Hannaford (CAOUS)

Lasers offer the potential for painless, non-contact treatmentof teeth in dentistry. The problems in applying conventionallasers for removal of hard dental tissues include poor surfacepreparation (cracking or fissures in the prepared surface),collateral (thermal) damage to the surrounding part of thetooth and especially the pulp, and slow removal rates(limited by the thermal load on the tooth) compared withthose offered by the mechanical drill. The recent availabilityof femtosecond lasers with millijoule pulse energies andkilohertz repetition rates offers excellent precision via non-thermal ablation.

Laser pulses of 80-150 fs duration and repetition rates of 1 kHz from the Swinburne Femtosecond Laser Facility andthe ANU Femtosecond Laser Source have been used toablate dental enamel from extracted human teeth with verypromising results [1]. The surface preparation of the teeth isexcellent, as observed by optical and scanning electronmicroscopy: there is no visible cracking or fissures and theablated surface is roughened which facilitates adhesion offilling material. The pulpal temperature, as measured by anembedded thermocouple, shows rises of up to 100C over a200 s treatment period. Flowing air over the tooth duringlaser treatment reduces this rise to less than 50C, which isbelow the pain limit.

1. A.V. Rode, E.G. Gamaly, B. Luther-Davies, B.T. Taylor, J. Dawes,A. Chan, R.M. Lowe and P. Hannaford, J. Appl. Phys. (in press)

QUANTUM INFORMATION

12

Decoherence in Quantum Computation Bryan Dalton, Tien Kieu

In the standard approach to quantum computation, thefundamental building block is the quantum bit, or qubit. Thisis a generalisation of the binary bit of classical computing,but unlike the binary bit a qubit can be in a quantumsuperposition of its two states. Upon measurement thesuperposition is destroyed, revealing one of the two classicalvalues of the qubit. One of the key advantages that quantumcomputers are expected to have over classical computers isin the area of computational complexity, (where complexityhere refers to the way computation time increases with thesize of the number being processed), an advantage based onfeatures of quantum parallelism (superposition) and quantumentanglement. In the quantum case the number ofcomputational steps required to complete a calculation forcertain algorithms is expected to increase much more slowlywith the size of the input numbers being processed than forclassical computers, such as the exponential improvement inthe factorisation of integers (Shor’s algorithm).

However, the physical system whose quantum states definethe N qubit system embodying the registers of the quantumcomputer is never completely isolated from the environment.Similarly, the quantum devices involved in the gatingprocesses that define the computational algorithm alsocouple to the outside world. In general, the density operatordescribing the state of the quantum computer does notremain pure and is changed by the system-environmentinteractions into a mixed state, with the coherences betweenthe different evolved input states being partially orcompletely destroyed. This process of decoherence is theenemy of quantum computation.

We are investigating the limits decoherence places on theimplementation of practical quantum computers and howdecoherence rates scale with the number of qubits. A betterunderstanding of scaling effects may lead to models forquantum computers that are less affected by decoherence.

Quantum Adiabatic Computation Tien Kieu (CAOUS), Alan Head (CSIRO)

The general notion of computability has been defined interms of the Church-Turing thesis with the introduction of theidealised “universal Turing machine”. Turing was able tocapture the essence of computation processes andalgorithms: What can be effectively computed is alsocomputable by Turing machines, and vice versa. If a functioncannot be computed at some given argument then thecorresponding Turing machine cannot stop upon acceptingthe equivalent input. The famous Turing halting problem isthat it can be shown there exists no general way to determinein advance whether a Turing machine, upon accepting someinput, would eventually halt or continue on forever. For 70years the Turing halting problem has occupied a centralposition in Mathematics and Theoretical Computer Scienceand has set the limits of what is classically computable.

Quantum computation based on qubits has recently beenshown to offer better performance over classical

computation in terms of reducing the complexity ofcomputation processes. However, quantum algorithms andall others discovered so far are only applicable to classicallycomputable functions. There remains the class of classicallynoncomputable functions, such as in the halting problem forTuring machines [1]. It is widely believed that quantumcomputation does not result in any advances regardingcomputability. Contrary to this belief, we propose ageneralised quantum computation that may be able tocompute the noncomputables. The idea is to encode thesolution of some problem to be solved into the ground state,|g>, of some Hamiltonian, HP. As it is easier to implementthe Hamiltonian than to obtain the ground state, thecomputation is started in a different and readily obtainableinitial ground state, |gI>, of some initial Hamiltonian, HI, andthen this Hamiltonian is deformed into the Hamiltonianwhose ground state is the desired one. If the deformationtime is sufficiently long, the initial state will evolveadiabatically into the desired state with a high probability.

We have recently proposed a quantum algorithm for theclassically noncomputable Hilbert’s tenth problem [2], whichis ultimately linked to the halting problem for Turingmachines in the computation of partial recursive functions.If such a scheme can be realised, the notion of effectivecomputability is extended well beyond the Church-Turingthesis. To investigate the limitation of the quantum algorithm,we are also studying other problems [3] which belong tofurther classes of noncomputable functions.

1. H. Rogers, Theory of Recursive Functions and Effective Computability(MIT Press, 1987)

2. T.D. Kieu, submitted to Phys. Rev. A, http://xxx.lanl.gov/abs/quant-ph/0110136 (2001); submitted to Proc. Roy. Soc. Lond.,http://xxx.lanl.gov/abs/quant-ph/0111063 (2001); submitted toContemp. Phys., http://xxx.lanl.gov/abs/quant-ph/0203034 (2002)

3. T.D. Kieu, submitted to Quantum Information and Computation,http://xxx.lanl.gov/abs/quant-ph/0111062 (2001)

Quantum Measurement Tien Kieu, Bryan Dalton

The issue of quantum measurement is central to ourunderstanding of quantum mechanics and plays a key role inthe development of quantum algorithms. Quantummechanics only offers a recipe for the outcomes ofmeasurement, but not an explanation of the process [1].We have been one of the first to investigate this problemusing Quantum Field Theory (QFT) [2]. We are exploring theuse of the inequivalent unitary representations of QFT as abasis for describing the possible outcomes of a quantummeasurement. Such inequivalence is admissible herebecause of the infinitely many degrees of freedom in QFT,but not in the standard quantum mechanics of systems withfixed and finite numbers of particles. The description of theinfinitely many degrees of freedom in macroscopicmeasuring devices may be facilitated using this QFTapproach.

1. J. von Neumann, Mathematical Foundations of Quantum Mechanics(Princeton Univ. Press, 1955)

2. M. Danos and T.D. Kieu, Int. J. Mod. Phys. E8, 257 (1999)

1313

PUBLICATIONS

Research Publications1. High-aspect ratio micromachining of polymers with

an ultrafast laser.Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo, Appl. Surface Sci. 186, 345-351 (2002).

2. Ultrafast laser spectroscopy of metalloporphyrins.C.N. Lincoln, J.A. Bolger, R.M. Lowe, W.J. Rowlands andP. Hannaford, Proc. Sixth Int. Conf. on Optics Within LifeSciences (in press).

3. Three-pulse two-colour photon echo and transientgrating studies of myoglobin.C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and P. Hannaford, Femtochemistry V (World Scientific, in press).

4. Isotope shift studies in Zr I by Doppler-freesaturated absorption spectroscopy and pseudo-relativistic Hartree-Fock calculations. I Transitions4d35s-4d25s5p.S. Bouazza, D.S. Gough, P. Hannaford, M. Wilson and C. Lim, J. Phys. B 35, 651-662 (2002).

5 Isotope shift studies in Zr I by Doppler-freesaturated absorption spectroscopy and pseudo-relativistic Hartree-Fock calculations. II Transitions4d25s2-4d25s5p.S. Bouazza, D.S. Gough, P. Hannaford and M. Wilson,J. Phys. B (in press).

6. Subpicosecond laser ablation of dental enamel.A.V. Rode, E.G. Gamaly, B. Luther-Davies, B.T. Taylor,J. Dawes, A. Chan, R.M. Lowe and P. Hannaford,J. Appl. Phys. (in press).

7. Femtosecond three-pulse photon echo andpopulation grating studies of the optical propertiesof CdTe/ZnSe quantum dots. L.V. Dao, R.M. Lowe, P. Hannaford, H. Machino and T. Yao,Appl. Phys. Lett. (submitted).

8. Spectrally resolved two-colour three-pulse photonecho studies of vibrational dynamics in molecules.L.V. Dao, C.N. Lincoln, R.M. Lowe and P. Hannaford,Physica B (submitted).

9. A reformulation of the Hilbert’s tenth problemthrough quantum mechanics. T.D. Kieu, Proc. Roy. Soc. Lond. (submitted),http://xxx.lanl.gov/abs/quant-ph/0111063 (2001).

10. Quantum algorithm for the Hilbert’s tenth problem. T.D. Kieu, Phys. Rev. A (submitted),http://xxx.lanl.gov/abs/quant-ph/0110136 (2001).

11. Hilbert’s incompleteness, Chaitin’s Ω number andquantum physics.T.D. Kieu, Quantum Information and Computation(submitted), http://xxx.lanl.gov/abs/quant-ph/0111062(2001).

12. Computing the noncomputables. T.D. Kieu, Contemp. Phys. (submitted),http://xxx.lanl.gov/abs/quant-ph/0203034 (2002).

13. Unitary and quantum computation.T.D. Kieu, in Experimental Implementation of QuantumComputation (ed. R.G. Clark), Rinton Press Inc., pp 348-351 (2001).

14. Quantum principles and mathematicalcomputability.T.D. Kieu, Philosophica Mathematica (submitted).

15. Doppler-free saturated absorption spectroscopy ofnatural lead in the near-ultraviolet.S. Bouazza, D.S. Gough, P. Hannaford, R.M. Lowe and M. Wilson, Phys. Rev. A 63, 012516-012522 (2001).

16. Micron-scale magnetic structures for atom optics.*A.I. Sidorov, R.J. McLean, B.A. Sexton, D.S. Gough,T.J. Davis, A.M. Akulshin, G.I. Opat and P. Hannaford,Comptes Rendus de l’Academie des Sciences 2,Series IV, 565-572 (2001).

17. Hyperfine structure of odd-parity levels in 91Zr I.S. Bouazza, D.S. Gough, P. Hannaford and M. Wilson,J. Phys. B 33, 2355-2365 (2000).

18. Sir Alan Walsh 1916-1998.*P. Hannaford, Hist. Rec. Aust. Sci. 13 (2), 45-72 (2000).

19. Sir Alan Walsh 1916-1998.*P. Hannaford, Biogr. Mem. Fell. R. Soc. Lond. 46, 533-564(2000).

20. Sub-Doppler laser cooling of fermionic 40K atoms.G. Modugno, C. Benko, P. Hannaford, G. Roati and M. Inguscio, Phys. Rev. A 60, R3373-6 (1999).

21. Reflection of cold atoms from an array of current-carrying conductors.*D.C. Lau, A.I. Sidorov, G.I. Opat, R.J. McLean,W.J. Rowlands and P. Hannaford,Eur. Phys. J. D 5, 193-9 (1999).

22. Magnetic mirrors with micron-scale periodicities forslowly moving neutral atoms.*D.C. Lau, R.J. McLean, A.I. Sidorov, D.S. Gough,J. Koperski, W.J. Rowlands, B.A. Sexton, G.I. Opat and P. Hannaford, J. Optics B: Quantum Semiclass. Opt. 1,371-7 (1999).

23. Magnetic atom optical elements for laser-cooledatoms.*D.C. Lau, R.J. McLean, A.I. Sidorov, D.S. Gough,J. Koperski, W.J. Rowlands, B.A. Sexton, G.I. Opat and P. Hannaford, J. Kor. Phys. Soc. 35, 127-32 (1999).

24. Atomic absorption with ultracold atoms.*P. Hannaford and R.J. McLean,Spectrochim. Acta, Part B 54, 2183-94 (1999).

25. The oscillator strength in atomic absorptionspectroscopy.*P. Hannaford, Microchem. J. 63, 42-52 (1999).

26. A magneto-optically recorded mirror for cold atoms.*D.S. Gough, R.J. McLean, A.I. Sidorov, D.C. Lau,J. Koperski, W.J. Rowlands, B.A. Sexton and P. HannafordIn Laser Spectroscopy (eds. R. Blatt et al),World Scientific, Singapore, pp 340-1 (1999).

14

Other Publications 1. 2001 Physics Nobel Prize goes to Bose-Einstein

Condensation. P. Hannaford and W.J. Rowlands, The Physicist 38,143-149 (2001).

2. Alan Walsh and the atomic absorptionspectrophotometer.P. Hannaford, The Physicist 38, 41-48 (2001).

3. Report on the Fifteenth International Conference onLaser Spectroscopy.P. Hannaford, Aust. Opt. Soc. News 15, 19-23 (2001).

4. “The storage of light” and very large variations ofthe group velocity of light in coherently preparedatomic media.A.M. Akulshin and G.I. Opat, Aust. Opt. Soc. News 15,30-35 (2001).

5. The Swinburne Optronics and Laser Laboratories(SOLL). W.J. Rowlands, Aust. Opt. Soc. News 14, 13-17 (2000).

* Relevant work performed whilst at CSIRO.

PUBLICATIONS

1515

CONFERENCES

ConferencesInternational Conference on ExperimentalImplementation of Quantum ComputationSydney, Australia, 16-19 January 2001.

1. Unitarity constraints in quantum computing.T.D. Kieu.

15th International Conference on Laser SpectroscopySnowbird, USA, 11-15 June 2001.

2. A high-quality, micron periodicity, grooved magnetic mirrorfor atom optics.A.I. Sidorov, R.J. McLean, B.A. Sexton, T.J. Davis,D.S. Gough, P. Hannaford, A.M. Akulshin and G.I. Opat.

Femtochemistry VToledo, Spain, 2-6 September 2001.

3. Three-pulse two-colour photon echo and transient gratingstudies of myoglobin.C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and P. Hannaford.

Multi-Dimensional Microscopy 2001Melbourne, 25-28 November 2001.

4. Femtosecond coherence spectroscopy (Invited Talk).C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and P. Hannaford.

Australasian Conference on Optics, Lasers andSpectroscopyBrisbane 3-6 Dec, 2001.

5. Light propagation in nonlinear media with very steepdispersion.A.M. Akulshin, A. Cimmino, B. Cantwell, P. Hannaford,R.J. McLean, A.I. Sidorov, and G.I. Opat.

6. High-quality, micron-scale, grooved magnetic mirrors foratom optics.R.J. McLean, A.I. Sidorov, D.S. Gough, F. Scharnberg,B.A. Sexton, T.J. Davis, A.M. Akulshin, G.I. Opat and P. Hannaford.

7. Femtosecond coherence spectroscopy of thephotodissociation of MbCO.C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and P. Hannaford.

8. Spectral analysis of 2-colour 3-pulse photon echoes on afemtosecond time scale.D.V. Dao, C.N. Lincoln, R.M. Lowe, W.J. Rowlands and P. Hannaford.

9. Subpicosecond laser ablation of dental enamel.A.V. Rode, E.G. Gamaly, B. Luther-Davies, B.T. Taylor,J. Dawes, A. Chan, R.M. Lowe and P. Hannaford.

10. Micro-machining of GaN films by ultrafast laser ablation.L.V. Dao, R.M. Lowe and P. Hannaford.

11. Correlations between the field and specific mass isotopeshifts in atomic spectral lines.P. Hannaford, D.S. Gough and S. Bouazza.

12. Permanent magnetic microstructures in integrated atomoptics.A.I. Sidorov, T.J. Davis, R.J. McLean, D.S. Gough,P. Hannaford and G.I. Opat.

13. Femtosecond Ramsey interference spectroscopy.R.M. Lowe, L.V. Dao, C.N. Lincoln, W.J. Rowlands and P. Hannaford.

14. Quantum computation and mathematical decidability.T.D. Kieu.

15. Ultrafast spectroscopy using ultracold molecules.H. Kitson and W.J. Rowlands.

Workshop on Truths and Proofs Auckland, New Zealand 7-8 December 2001.

16. Quantum principles and mathematical computability.(Invited Talk).T.D. Kieu.

Bose-Einstein Condensation WorkshopKioloa, Australia, 30 January-3 February 2000.

17. Sub-Doppler laser cooling of fermionic 40K.G. Modugno, C. Benko, P. Hannaford, G. Roati and M. Inguscio.

Sixth International Conference on Optics Within LifeSciencesSydney, 22-24 February 2000.

18. Ultrafast laser spectroscopy of metalloporphyrins.C.N. Lincoln, J.A. Bolger, R.M. Lowe, W.J. Rowlands andP. Hannaford.

Seventeenth International Conference on AtomicPhysicsFlorence, Italy, 4-9 June 2000.

19. Microfabricated magnetic structures for cold atom optics.D.S. Gough, R.J. McLean, A.I. Sidorov, T.J. Davis,B.A. Sexton, P. Hannaford and G.I. Opat.

First International Symposium on Laser PrecisionMicrofabrication,Omiya, Saitama, Japan, 15-16 June, 2000.

20. Formation of a micro-string array in transparentmaterials exposed to a beam of 100 fs laser pulses.Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo.

Workshop on Recent Progress with Trapped Ions andAtoms,Innsbruck, 16 June 2000.

21. Micron-scale magnetic structures for atom optics (Invited Talk).P. Hannaford, D.S. Gough, R.J. McLean, A.I. Sidorov,T.J. Davis, B.A. Sexton and G.I. Opat.

16

CONFERENCES

Sixth International Workshop on Atom Optics andInterferometryCargese, Corsica 26-29 July, 2000.

22. Micron-scale magnetic structures for atom optics (Invited Talk).A.I. Sidorov, R.J. McLean, B.A. Sexton, D.S. Gough,T.J. Davis, A. Akulshin, G.I. Opat and P. Hannaford.

23. Ultracold collisions of fermionic potassium in an opticaldipole trap.G. Modugno, G. Roati, P. Hannaford and M. Inguscio.

Tenth International Conference on Non-Resonant Laser-Matter InteractionSt. Petersburg, Russia, 21-23 August 2000.

24. Micro-string arrays formed in transparent materialsunder 100-fs laser pulses.Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo.

Fall Meeting of the Japanese Applied Physics SocietySapporo, Hokkaido, Japan, 2-6 September, 2000.

25. Formation of a micro-string array in transparentmaterials with a femtosecond laser beam.Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo.

XI European Conference on Quantum OpticsMallorca, Spain, 14-19 October, 2000.

26. Microfabricated magnetic mirrors for cold atoms.D.S. Gough, R.J. McLean, A.I. Sidorov, T.J. Davis,B.A. Sexton, P. Hannaford and G.I. Opat.

Thirteenth Conference of the Australian Optical SocietyAdelaide, 12-15 December 2000.

27. Specular reflection of ultracold atoms frommicrofabricated magnetic mirrors.A.I. Sidorov, R.J. McLean, A.M. Akulshin, D.S. Gough,B.A. Sexton, T.J. Davis, P. Hannaford and G.I. Opat.

28. Ultrafast laser spectroscopy of haemoproteins.C.N. Lincoln, J.A. Bolger, R.M. Lowe, W.J. Rowlands andP. Hannaford.

29. Interaction of ultrashort laser pulses with transparentpolymers.R.M. Lowe, Y. Zhang, E.C. Harvey and P. Hannaford.

Fifth International Conference on Atom Optics and AtomInterferometry Sylt, Germany 8-11 March, 1999.

30. Microfabricated magnetic optics for slowly moving optics(Invited Talk).D.S. Gough, D.C. Lau, R.J. McLean, J. Koperski,W.J. Rowlands, B.A. Sexton, A.I. Sidorov, G.I. Opat and P. Hannaford

Fourth International Conference on Laser Spectroscopy,Innsbruck, Austria, 7-11 June, 1999.

31. A magneto-optically recorded mirror for cold atoms.D.S. Gough, R.J. McLean, A.I. Sidorov, D.C. Lau,J. Koperski, W.J. Rowlands, B.A. Sexton, P. Hannafordand G.I. Opat

Twelfth Conference of the Australian Optical Society,Sydney, Australia, 4-9 July, 1999.

32. Matter-wave optics in Melbourne (Invited Talk).P. Hannaford

1717

SEMINARS AND MEDIA PRESENTATIONS

Seminars1. Atom Optics at Swinburne.

R.J. McLean, The University of Melbourne, 27 April 2001.

2. Quantum computing: information processed through theprinciples of quantum mechanics.T.D. Kieu, Swinburne University of Technology,18 May 2001.

3. Magnetic optics for slowly moving atoms.P. Hannaford, Stanford University, USA, 8 June 2001.

4. The laser spectroscopy program at Swinburne Universityof Technology.P. Hannaford, University of Queensland, 10 July 2001.

5. Photoluminescence studies of semiconductornanostructures.L.V. Dao, Swinburne University of Technology,10 August 2001.

6. Optical properties of intermixed quantum structures.L.V. Dao, Tohoku University, Sendai, Japan,10 October 2001.

7. Quantum algorithms and the notion ofdecidability/computability.T.D. Kieu, The University of Melbourne, 10 October 2001.

8. Can quantum computing resolve the Turing haltingproblem?T.D. Kieu, Swinburne University of Technology,19 October 2001.

9. Research at the Swinburne Optronics and LaserLaboratories.P. Hannaford, The University of Melbourne,24 October 2001.

10. The 2001 Nobel Prize in Physics.P. Hannaford and W.J. Rowlands, The Australian Instituteof Physics, The University of Melbourne,25 October 2001.

11. Magnetic optical elements for slowly moving atoms.P. Hannaford, University of Innsbruck, Austria,20 June 2000.

12. Highlights of the Sixth International Workshop on AtomOptics, Cargese, Corsica.P. Hannaford, The University of Melbourne,16 August 2000.

13. The Swinburne University Femtosecond Laser Facility.P. Hannaford, Swinburne University of Technology,26 February 1999.

14. Microfabricated magnetic optics for slowly movingatoms.P. Hannaford, European Laboratory for NonlinearSpectroscopy, Florence, 23 March 1999.

15. Microfabricated magnetic optics for slowly movingatoms.P. Hannaford, University of Pisa, Italy, 17 March 1999.

Media Presentations1. New Scientist:

“Smash and grab”. Computing the noncomputables.Review by Chown Marcus,6 April 2002.

2. The ABC Quantum program:The Swinburne Femtosecond Laser Facility.Presented by Paul Willis,22 May 2000.

3. The ABC Science Show:Professor Ahmed Zewail and the SwinburneFemtosecond Laser Facility.Presented by Robyn Williams,27 February 1999.

18

Competitive Grants1. ARC Discovery Grant (2002 $72,000; 2003 $100,000;

2004 $31,000).A.I. Sidorov, P. Hannaford, R.J. McLean, G.I. Opat,T.J. Davis.Integrated atom optics: guiding matter waves withmagnetic microstructures.

2. ARC Discovery Grant (2002 $70,000).W.J. Rowlands.Generation and application of ultracold molecules.

3. ARC Linkage Infrastructure Grant (2002 $530,000).A.N. Luiten (UWA), D.D. Sampson (UWA), P. Hannaford(CAOUS), D.M. Kane (Macquarie).A transportable optical frequency counter, synthesiserand super-continuum generator.

4. ARC Research Development Grant (2002 $8,000).T.D. Kieu.Quantum computation.

5. Systemic Infrastructure Initiative Grant (2002$1,674,000; 2003 $151,000; 2004 $151,000).P. Hannaford (CAOUS), A. Mazzolini (CIAO), E.C. Harvey(IRIS), M. Gu (CMP), M.W. Austin (RMIT University).Integrated microfabrication facility.

6. ARC Research Infrastructure Equipment and Facilities(RIEF) Grant (2001 $480,000).K. P. Ghiggino (Univ. Melb.), T.A. Smith (Univ. Melb.),P. Hannaford (CAOUS), W.J. Rowlands (CAOUS),M. Gu (CMP), X. Gan (CMP).Ultrafast microspectroscopy facility.

7. ARC Small Grant (2000 $15,000).E.C. Harvey and P. Hannaford.Ultra-short pulsed laser ablation for micromachining.

International CollaborationsEuropean Laboratory for Nonlinear Spectroscopy (LENS),Florence, Italy (Prof Massimo Inguscio, Dr Giovanni Modugno)

Massachusetts Institute of Technology, Cambridge, USA(Dr Edward Farhi)

Nanyang Technological University, Singapore (Prof Shu Yuan)

North Eastern University, Boston, USA (Dr Sam Gutmann)

Sumitomo Heavy Industries, Japan (Dr Yanping Zhang)

The Femtosecond Technology Research Association,Japan (Dr Akira Endo)

Tohoku University, Sendai, Japan (Prof Takafumi Yao,Dr Hisao Makino)

Tulane University, New Orleans, USA (Dr Mike Wilson)

University of Reims, France (Dr Safa Bouazza)

National Collaborations Australian National University, Canberra (Dr Andrei Rode,Dr Eugene Gamaly, Prof Barry Luther-Davies)

CSIRO Manufacturing Science and Technology, Melbourne (Dr Tim Davis, Dr Brett Sexton, Prof Alan Head)

Industrial Research Institute Swinburne (IRIS), Melbourne (Dr Erol Harvey)

Royal Melbourne Hospital (Dr Andrew Rawlinson)

RMIT University (Dr Arnam Mitchell, Prof Mike Austin)

The University of Melbourne, Physics (Prof Geoffrey Opat,Dr Alexander Akulshin)

The University of Melbourne, Chemistry (Prof Ken Ghiggino,Dr Trevor Smith)

The University of Western Australia, Perth (Dr Andre Luiten)

COMPETITIVE GRANTS AND COLLABORATIONS

1919

VISITING POSITIONS, HONOURS AND AWARDS

Visiting Positions, Honours and Awards

Lap Van DaoAustralian Academy of Science Exchange Fellowship,Tohoku University, Sendai, Japan (October 2001)

Peter HannafordElsevier Spectrochimica Acta Atomic Spectroscopy Award(2001)

Guest Professorship, University of Innsbruck, Austria (June 2000)

Visiting Scientist, European Laboratory for NonlinearSpectroscopy (LENS), Florence, Italy, (June-July 2000)

Tien KieuVisiting Scientist, Massachusetts Institute of Technology(MIT), Cambridge, USA (June 2001)

Australian Academy of Science Exchange Fellowship,MIT and Princeton, USA (May-June 2002)

Invited review article for Contemporary Physics (2001)

Craig LincolnIAESTE Exchange Studentship, University of Vienna, Austria(August-September 2001)

Russell McLeanElsevier Spectrochimica Acta Atomic Spectroscopy Award(2001)

Geoffrey OpatOrder of Australia (2002)

Further information

Centre for Atom Optics and Ultrafast Spectroscopy (CAOUS)

School of Biophysical Sciences and Electrical Engineering

Swnburne University of TechnologyJohn StreetHawthorn Victoria Australia 3122

Telephone: +61 3 9214 5164Facsimile: +61 3 9214 5840Web: www.swin.edu.au/lasers/caous