Swinburne University of Technology Melbourne, Australia Centre for Atom Optics and Ultrafast Spectroscopy Research Report 2001 CONTENTS

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 1 – 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 PREFACE

The Swinburne Centre for Ultrafast Laser Spectroscopy molecule, carbonmonoxy myoglobin. We have also applied (SCULS) was opened on 26 February 1999 by Professor femtosecond Ramsey interference techniques to ‘observe’ Ahmed Zewail, 1999 Chemistry Nobel Laureate, as part of the full cycle of an optical transition in rubidium as it evolves the new Swinburne Optics and Laser Laboratory (SOLL) in time with a period of about 2 femtoseconds. In Quantum complex. The Centre, which is funded by a Swinburne Information, Tien Kieu has proposed a quantum computation Strategic Initiative Grant, initially comprised a state-of-the-art ‘algorithm’ for one of the insoluble problems of mathematics, Femtosecond Laser Facility housed in a new purpose-built the Hilbert’s tenth problem, which is ultimately linked to the laboratory and two personnel, Martin Lowe and myself, both halting problem for Turing machines. A number of papers seconded on a part-time basis from CSIRO. Later that year resulting from this work are currently attracting world-wide we were joined by PhD student Craig Lincoln, Dr Jeremy attention. Bolger from Redstone Australia Mining and Dr Wayne Rowlands from Yale University. Details of the research activities of CAOUS are presented in subsequent sections. It is rewarding to see a steady stream In February 2001 the Atom Optics Group at CSIRO, of publications already flowing from our research and the comprising Dr Russell McLean, Dr Andrei Sidorov, David work being reported at the major international conferences. Gough and myself, moved to Swinburne University to join the At the recent Australasian Conference on Optics, Lasers and SCULS group, to form the Centre for Atom Optics and Spectroscopy in Brisbane, the group contributed six oral and Ultrafast Spectroscopy (CAOUS). We are most grateful to five poster presentations. In 2003 we will be co-hosting the Swinburne University for start-up funding to establish the 16th International Conference on Laser Spectroscopy, which new Atom Optics laboratory and to CSIRO for allowing us to is the premier forum for the announcement of new world- bring the laser and optics equipment with us. In 2001 we wide developments in laser spectroscopy and related fields. were also joined by Dr Tien Kieu from CSIRO to initiate research in quantum information, Dr Lap Van Dao from the In the 2002 round of ARC grants, CAOUS was successful in University of NSW to work on ultrafast spectroscopy, and two securing two Discovery Grants, a Linkage Infrastructure new PhD students, Heath Kitson and Falk Scharnberg. We Grant (with the University of WA and Macquarie University), 3 were fortunate to also gain the part-time services of two and a Research Development Grant. We were also awarded a adjunct professors, Professor Alan Head from CSIRO and $1.98M Systemic Infrastructure Initiative grant (with the Professor Geoffrey Opat from the University of Melbourne. Swinburne CIAO, CMP and IRIS groups and RMIT University) In 2002 we welcomed two new researchers, Associate from the Federal Government to establish an Integrated Professor Bryan Dalton from the University of Queensland Microfabrication Facility. These grants are in addition to a and Dr Barbara McKinnon from Monash University. Research Infrastructure Equipment and Facilities (RIEF) grant (with the University of Melbourne and the Swinburne CMP) in This Report covers the first three years’ activities of 2001. CAOUS/SCULS, from 1999 to 2001. The primary objective of the Centre is to carry out fundamental and strategic research I wish to take this opportunity to thank the various members in the areas of Atom Optics, Ultrafast Spectroscopy, and of CAOUS for their efforts in getting the new laboratories up Quantum Information. These three areas are among the and running so quickly, and especially Dr Jeremy Bolger for topics listed in the Federal Government’s recently designated spending a year with us helping to establish the priority research area of Photon Science and Technology. In femtosecond laser laboratory. We particularly wish to thank Atom Optics, we are developing high-quality atomic optical the Vice-Chancellor, Professor Iain Wallace, the Pro Vice- elements, including mirrors, beamsplitters, surface Chancellor (Research), Professor Kerry Pratt, and the Head of waveguides and surface microtraps, for manipulating beams the School of Biophysical Sciences and Electrical of ultracold laser-cooled atoms, and we are using laser- Engineering, Professor David Booth, for their continued cooled atoms to generate samples of ultracold molecules. support and encouragement. We have recently observed near-specular reflection of a Shortly before this Report went to press, we were shocked cloud of ultracold rubidium atoms dropped onto magnetic and deeply saddened to learn of the sudden and premature microstructures with periodicities of around a micron. In death of our friend and colleague, Professor Geoffrey Opat Ultrafast Laser Spectroscopy, we are developing AO FAA, collaborator of the Atom Optics group since 1991 femtosecond coherent nonlinear techniques, including and Adjunct Professor of this university since 2001. Geoff stimulated photon echoes, transient grating and Ramsey had a profound influence on the lives, scientific careers and interference techniques, to investigate ultrafast processes in research work of many of us and will be greatly missed. complex molecular systems, including biological molecules, dye molecules and semiconductor quantum dots, on time Peter Hannaford, Director of CAOUS scales down to less than 10-13 s. We have successfully used March, 2002 femtosecond three-pulse photon echo techniques to investigate the photodissociation of the biologically important CONTACT INFORMATION

Centre for Atom Optics and Research Associates Ultrafast Spectroscopy (CAOUS) Dr Alexander Akulshin School of Biophysical Sciences and Electrical Engineering (The University of Melbourne) Swinburne University of Technology PO Box 218 Dr Tim Davis Hawthorn Victoria Australia 3122 (CSIRO Manufacturing Science and Technology)

Phone +61 (0)3 9214 5164 (Peter Hannaford) Dr Khai Vu Fax +61 (0)3 9214 5840 Dr Margaret Wong Website http://www.swin.edu.au/lasers/caous (School of Engineering and Science, Swinburne University)

Staff Undergraduate students Prof Peter Hannaford (Director) Shannon Whitlock [email protected] Ext 5164 Honours student in Optronics and Lasers (2002)

A/Prof Bryan Dalton Jack Manning [email protected] Ext 8187 Engineering and Science R&D student (2002)

Dr Lap Van Dao Pascal Rouviere [email protected] Ext 4317 Internship student from Paris (to start 2002)

Mr David Gough Adam Deller [email protected] Ext 4308 Engineering and Science R&D student (finished 2001)

Prof Tien Kieu Christoph Rill [email protected] Ext 8026 Exchange student from Vienna (finished 2001) Mr Martin Lowe 4 Lee Manuele [email protected] Ext 4309 Work experience student (finished 2001)

Dr Barbara McKinnon Ivan Blajer [email protected] Ext 8187 Summer vacation student (finished 2001)

Prof Russell McLean Christine Aussibal [email protected] Ext 8555 Internship student from Paris (finished 2000)

Dr Wayne Rowlands Mara Giovannetti [email protected] Ext 8142 Final Year Chemistry student (finished 2000)

Prof Andrei Sidorov Joshua Pearce [email protected] Ext 5848 Engineering and Science R&D student (finished 2000)

Dr Jeremy Bolger (finished 2000) Trent Boyce Mr Peter Larkins (finished 2000) Engineering and Science R&D student (finished 1999)

PhD students How to find us Heath Kitson The Centre for Atom Optics and Ultrafast Spectroscopy is [email protected] Ext 5680 housed in a modern, purpose-built laboratory complex, the Craig Lincoln Swinburne Optics and Laser Laboratories, on the ground [email protected] Ext 5680 floor of the Applied Sciences building, at Swinburne University’s Hawthorn Campus, 7 kms from the heart of Falk Scharnberg Melbourne (Melways Directory, map 45, grid reference [email protected] Ext 5680 E-10). The entrance to CAOUS is in Serpells Lane, off Burwood Road, and next to Glenferrie Station, which is well Xiaoming Wen (to start 2002) served by trains on the Lilydale, Belgrave and Alamein lines. For parking we advise a nearby multi-storey car park in Adjunct professors Wakefield Street, off Glenferrie Road. Prof Alan Head AO FAA FRS (CSIRO Manufacturing Science and Technology)

Prof Geoffrey Opat AO FAA (The University of Melbourne) ATOM OPTICS

Atom Optics Laser light may now be used to cool a cloud of atoms to within a few microkelvin of absolute zero, where the atoms behave like waves, with de Broglie wavelengths comparable NNNN N to the wavelength of light. This has opened up a new field of SSSS S optics, ‘Atom Optics’, in which beams of slowly moving atoms can be reflected, diffracted and made to interfere in much the same way as beams of light. Interferometers based on beams of slowly moving atoms can be extremely Figure 1b Magnetic field distribution above a periodic grooved sensitive to quantities such as gravity fields and their magnetic structure. gradients, accelerations and rotations of the reference frame. To produce a ‘hard’ magnetic mirror with small decay length CAOUS has two large Atom Optics laboratories which house and to be able to use the magnetic structures as diffractive three laser-cooling and trapping set-ups, a single-mode beamsplitters, the periodicity of the structure needs to be titanium sapphire laser (Coherent 899) pumped by a small, preferably about a micron. Generating sufficiently 10 W Millennia Nd:YVO4 laser, a single-mode ring dye laser strong and uniform magnetic fields above such fine (Spectra-Physics 380D), a 50 W CO2 laser (Deos GEM-50), structures has proven to be a challenge, but we have three Tui Optics single-mode diode lasers, and two Princeton recently succeeded in producing very promising, micron- Instruments CCD cameras. We are currently establishing a period magnetic mirrors based on grooved,perpendicularly microfabrication laboratory comprising a semi-clean room magnetised CoCr structures [3] (Fig. 1b). These structures with a thin-film deposition system, a photolithography mask are fabricated using electron-beam lithography to write a aligner, an optical confocal scanning microscope profilometer, grooved pattern in photoresist, from which a nickel master is and an atomic force/magnetic force microscope. replicated. 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 ranging ■ Magnetic Optical Elements for Ultracold Atoms from 0.7 to 4 µm have been successfully fabricated and Russell McLean, Andrei Sidorov, David Gough, characterised using atomic and magnetic force microscopy. Peter Hannaford (CAOUS), Alexander Akulshin, Geoffrey Opat 5 The magnetic mirrors have been tested by dropping a cloud (University of Melbourne), Brett Sexton, Tim Davis (CSIRO) of laser-cooled rubidium or caesium atoms onto the surface To exploit the potential of Atom Optics, high-quality atomic and recording laser-induced fluorescence signals from the optical elements including mirrors and beamsplitters are atom cloud in a CCD camera (Fig. 2, overleaf). Measurements needed. A novel approach, which we developed while at of the atom cloud at various times before and after reflection CSIRO, is based on the interaction between the magnetic reveal that the reflection is predominantly specular, with an moment of the atom and the exponentially decaying angular spread of less than about 10 mradians introduced by magnetic field above a periodic array of magnetic elements, imperfections in the mirror [3]. The accuracy of the where the decay length is determined by the periodicity of specularity measurements is presently limited by residual the array (Fig. 1a) [1, 2]. A magnetic mirror consisting of a curvature in the magnetic mirror introduced during periodic array of magnets may be converted into a magnetic fabrication and by the method of analysis. diffraction grating, or diffractive beamsplitter, for slowly This grooved type of magnetic structure appears to be the moving atoms by applying a small bias magnetic field most promising to date for producing high-quality magnetic perpendicular to the surface [1]. mirrors for ultracold atoms. It should be possible to improve the quality further by using TbGdFeCo films, which can have atom (mgF >0) excellent magnetic homogeneity and higher remanent magnetic 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)

a Figure 1a Magnetic field distribution above a periodic array of magnets of alternating polarity. Atoms in positive

magnetic states (mgF >0) are repelled by the increasing magnetic field strength above the array. ATOM OPTICS

Figure 2 Side view of the laser-induced fluorescence from a cloud Permanent magnets have potential advantages over current- of about one million ultracold rubidium atoms falling onto carrying conductors for generating microscopic magnetic and bouncing from a grooved magnetic microstructure of field structures. In particular thin-film magnetic structures periodicity 2 µm. Times after release of the atoms from can produce large magnetic field gradients (~107 G/cm) the laser-cooling optical molasses are shown. without the risk of excessive heating and potential breakdown of the current-carrying circuits. Use of permanent magnets also overcomes problems due to current variations, ■ Integrated Atom Optics imperfect insulation between conductors, and open and short 6 Falk Scharnberg, Andrei Sidorov, Russell McLean, circuits. David Gough, Peter Hannaford (CAOUS), Geoffrey Opat (University of Melbourne), Tim Davis (CSIRO) 1. J. Reichel, W. Hänsel and T.W. Hänsch, Phys. Rev. Lett. 83, 3398 (1999) Advances in lithography and microfabrication techniques 2. T.J. Davis, J. Opt. B: Quantum Semiclass. Opt. 1, 408 (1999) have recently led to the development of miniature surface- based current-carrying optical elements for manipulating ultracold atoms, allowing the construction of networks of (a) microtraps, waveguides, beamsplitters and couplers on the surface of a substrate [1] – ‘integrated atom optics’. Scaling down the dimensions of the optical elements has the advantage of allowing large magnetic field gradients and very tight confinement of the atoms at moderate electric currents. The tight confinement in a magnetic microtrap increases the vibrational quantum level splitting, allowing the splitting to exceed the photon recoil energy (Lamb-Dicke regime). This also increases the elastic collision rate between the ultracold atoms, thereby reducing the time to reach quantum degeneracy (Bose-Einstein condensation). (b) We are investigating the use of permanent magnetic films (CoCr or TbGdFeCo) with perpendicular magnetisation to construct surface-based microscopic magnetic traps, waveguides and beamsplitters for ultracold atoms [2], including Bose-Einstein condensates, with the objective of developing a integrated surface-based atom interferometer. A single magnetic strip or two separated magnetic strips, for example, can produce a two-dimensional quadrupole potential to form a microscopic waveguide for the propagation of atomic de Broglie waves (Fig. 3). A combination of magnetic strips and current-carrying wire loops can produce a surface microtrap that can be coupled Figure 3 Atom waveguides produced by a 2D quadrupole potential to a standard magneto-optical trap. above (a) a single permanent magnetic strip with bias magnetic field, and (b) two separated permanent magnetic strips. ATOM OPTICS

■ Ultracold Molecules Femtochemistry has previously permitted studies of Heath Kitson, Wayne Rowlands fundamental chemical processes in real-time [2], such as the dependence of reaction rates upon temperature (Arrhenius’s Two major advances in precision molecular spectroscopy in scaling law). We will be able to test the validity of these laws recent years have been the application of laser cooling and at temperatures very close to absolute zero, where quantum trapping techniques to molecules [1] and the application of mechanical effects dominate. ultrafast laser spectroscopic techniques to studies of molecular dynamics in real time (‘femtochemistry’) [2]. This 1. See, e.g., J.T. Barnes, P.L. Gould and W.C. Swalley, Adv. At. Mol. Opt. Phys. 42, 171 (2000). project aims to combine these two technologies to extend femtochemistry into the domain of ultracold atoms and 2. See, e.g., A.H. Zewail, J. Phys. Chem.A 104, 5660 (2000), and references therein. molecules.

Several techniques exist for the generation of ultracold ■ Light Propagation in Steeply Dispersive Atomic Media (T < 1 mK) molecules. The approach we are taking is to produce molecules by the photoassociation (‘light-assisted’ Alexander Akulshin, Alberto Cimmino, Geoffrey Opat collisions) of laser-cooled atoms. The initial work involves the (University of Melbourne), Andrei Sidorov, Russell McLean, Jack Manning, Peter Hannaford (CAOUS). formation of ultracold diatomic rubidium molecules, Rb2. There is much interest in optimising the production of Light-induced coherence between ground-state magnetic ultracold molecules, and particularly in having control over sublevels may cause extremely large enhancements of the the population of the vibrational and rotational molecular dispersion and nonlinear susceptibility of alkali atomic states. vapours. Depending upon the parameters of the optical The laser-cooling set-up that will be used to generate transition, the coherent superposition of sublevels may be samples of ultracold molecules is shown in Fig. 4. The either ‘dark’, producing electromagnetically induced photoassociated molecules will be captured in a far-off transparency, or ‘bright’, producing electromagnetically resonant optical dipole trap, based on a tightly focussed induced absorption [1]. An atomic gas prepared in a dark coherent state exhibits a very steep positive dispersion, infrared beam from a 50 W CO2 laser. Such an optical trap has a large detuning from all relevant atomic and molecular allowing light propagation with ultra-slow group velocity. 7 transitions, and thus long storage times are possible. The In a bright state the dispersion is also steep but negative [2], initial program is to use the trapped ensemble of ultracold leading to the counterintuitive situation of a negative group molecules for spectroscopic studies. However, there are also velocity in which the peak of a light pulse exits the atomic other possible applications, such as further cooling of the medium before it goes in [3]. ensemble to the transition point for molecular Bose-Einstein We are extending these investigations on bright and dark condensation. atomic states to samples of ultracold laser-cooled rubidium atoms to reduce the interaction times of the atoms and hence to increase the steepness of the dispersion of the atomic medium. The ability to slow and store light has potential 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)

Figure 4 Heath Kitson tweaking the laser-cooling set-up to be used for generating samples of ultracold molecules. ULTRAFAST LASER SPECTROSCOPY

Ultrafast Laser Spectroscopy transition, the population relaxation time T1 of the upper The Swinburne Femtosecond Laser Facility is used in a wide level, and the inhomogeneous broadening, which may arise, range of applications involving ultrafast phenomena in for example, from the fluctuating environment of surrounding physics, chemistry, biology and engineering. The Facility molecules. Furthermore, when the probe has a wavelength (shown in Fig. 5) is a Spectra-Physics system comprising a different from that of the pump pulses, it can systematically Tsunami mode-locked titanium sapphire laser pumped by a probe the population and coherences of excited levels or 5 W Millennia Nd:YVO4 laser; a Spitfire regenerative transient species at different internuclear separation as the amplifier; and two independently tunable optical parametric excited molecule evolves on a femtosecond time scale. In the amplifiers, with capabilities of second and fourth harmonic special case of coincident pump pulses (τ=0) the generation and sum frequency mixing of the signal and idler measurement becomes a transient grating (or transient four- beams. The system produces pulses of duration down to 50 wave mixing) experiment. Figure 6b shows three-pulse two- fs, pulse energies up to about 1 mJ (allowing peak colour photon echo signals k4,5 = k3 ±(k1 – k2) for the dye intensities up to about 1015 W cm-2), and wavelengths molecule, Rhodamine B (RhB) in methanol solution. Also covering the range 250-2500 nm. Other major equipment evident are some weak high (fifth) order photon echoes includes a 20 cm optical delay line with step size down to k6,7 = k3 ±2(k1 – k2), corresponding to two-photon 25 nm (0.2 fs), a molecular beam system, a femtosecond processes, as well as the two-pulse photon echo signals streak camera (Hamamatsu C5680), and an ultrafast gated 2k1 – k2,2k2 – k1, etc. intensified CCD imaging system (LaVision PicoStar HR). In order to interpret and analyse the multiple-pulse photon echo data, theoretical models involving the determination of high-order polarisations with multiple-time correlation functions are being developed.

8

Figure 6a Three-pulse photon echo experiment.

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

■ Femtosecond Photon Echoes The use of femtosecond coherent nonlinear techniques such as stimulated photon echoes provides a powerful method for investigating ultrafast transient processes, including energy transfer, charge transfer and laser-induced vibrational coherences, in complex molecular systems such as Figure 6b Three-pulse, two-colour (580, 610 nm) photon echoes biological molecules, dye molecules and semiconductors on (k4, k5) for Rhodamine B in methanol (see text). time scales down to the order of the vibrational period of a molecule (~10-13 s). Biological Molecules We are using a three-pulse photon echo technique, in which Craig Lincoln, Lap Van Dao, Martin Lowe, Wayne Rowlands, two excitation pulses and a third (probe) pulse with Shannon Whitlock, Barbara McKinnon, Peter Hannaford wavevectors k1, k2 and k3 (where k=2π/λ in the direction of τ propagation) and temporal separations t12= and t23=T We are investigating ultrafast transient processes in propagate through the sample (Fig. 6a). The sum of the biologically important molecules, including the electric fields emitted by different molecules having a spread photodissociation of carbonmonoxy myoglobin (MbCO) into of frequencies (inhomogeneous broadening) vanishes in all Mb and CO. Myoglobin is the single heme analogue of the directions except the ‘phase-matching’ directions, more complex haemoglobin and is responsible for the e.g., k4,5 = k3 ±(k1 – k2), along which the fields rephase at storage of oxygen in animals and plants. times near τ after the third pulse, giving rise to an ‘echo’ signal. The echo signal is recorded by scanning either the We use the transient grating technique in combination with a ‘coherence’ time τ or the ‘population’ time T. The additional three-pulse photon-echo peak shift (3PEPS) technique, in degree of freedom allowed by having a third pulse in a which the shift (∆τ) in peak temporal position of the two

three-pulse experiment enables one to extract the optical echo signals k4 and k5 is recorded as a function of dephasing time T2 (homogeneous broadening) of the population time T. The transient grating signals provide ULTRAFAST LASER SPECTROSCOPY

information on the population dynamics, while the 3PEPS The strong component at the central probe wavelength signals provide information on the inhomogeneous (640 nm), which represents a population grating signal broadening and laser-induced coherences essentially in the created by the two interacting pump pulses, has a very slow absence of population effects. The transient grating signal for decay (> 10 ps) corresponding to relaxation of the grating MbCO (Fig. 7a) can be analysed into three components, caused, for example, by intramolecular energy and charge having decay times of about 270 fs, 3 ps and >200 ps, transfer, while the weak component at 610 nm, which which are similar to the decay times associated with the represents a ‘pure’ echo signal, has a rapid decay (400 fs) recently proposed three stages of photodissociation of the due to dephasing of the optical transition. The rise times of related molecule, carbonmonoxy haemoglobin [1]. There is the echo signals at different detection wavelengths allow a also evidence of oscillations, which are associated with laser- determination of the relaxation times (80-200 fs) for the induced vibrational coherences in the electronic ground levels. initially excited vibrational level to lower vibrational levels in the excited state. The three-pulse photon echo signals for MbCO show significant peak shifts, indicating strong inhomogeneous broadening. The 3PEPS curve (Fig. 7b) consists of an initial rapidly decaying component (<100 fs) resulting from destructive interference of coupled vibrational wavepackets, followed by a slowly decaying oscillatory component which is associated with vibrational coherences in electronic excited states [2].

Figure 8 Spectrally resolved three-pulse, two-colour (520, 640 nm) 9 photon echo signals for RhB in methanol for different population times A: 110 fs, B: 300 fs, C: 350 fs, D: 400 fs, E: 450 fs. Inset: time evolution of echo intensity for three detection wavelengths 1: 610 nm, 2: 625 nm, 3: 640 nm.

1. L.V. Dao, C.N. Lincoln, R.M. Lowe and P. Hannaford, submitted to Figure 7 (a) One-colour (515 nm) transient grating and Physica B (b) one-colour three-pulse photon echo peak shift signals for carbonmonoxy myoglobin. Semiconductor Quantum Dots Lap Van Dao, Martin Lowe, Peter Hannaford (CAOUS) 1. S. Franzen, L. Kiger, C. Poyart and J-L. Martin, Biophys. J. 80, 2372 Hisao Makino, Takafumi Yao (Tohoku University, Japan) (2001) 2. C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and P. Hannaford, Semiconductor quantum dots in which the dot size is Femtochemistry V (World Scientific, in press) comparable to the exciton radii have unique electronic properties due to the effect of the three-dimensional confinement. We are using femtosecond three-pulse two- Spectrally Resolved Photon Echoes colour photon echo and population grating techniques to Lap Van Dao, Craig Lincoln, Martin Lowe, Barbara McKinnon, characterise cadmium telluride quantum dots grown on zinc Peter Hannaford selenide by molecular beam epitaxy [1]. The time evolution of the population grating signal shows a fast decay (2-3 ps), We are exploring the use of spectrally-resolved three-pulse, corresponding to migration and tunnelling of the exciton to two-colour stimulated photon echo techniques, in which the neighbouring quantum dots, followed by a slower decay wavelengths of the echo signals are analysed in a (20 ps to >100 ps) which is related to the lifetime of the spectrometer, allowing the population and dephasing exciton. components of the echo signal to be separated. Figure 8 shows spectra of the photon echo signal recorded for a The peak intensity of the three-pulse photon echo signals range of population times T (with τ=0) for RhB in methanol, versus population time T recorded at detection wavelengths where the wavelengths of the pump and probe beams are longer than the excitation wavelength (Fig. 9, overleaf) 520 nm and 640 nm, respectively [1]. A strong dependence exhibits a slowly decaying oscillatory quantum beat of the photon-echo signal on the population time T and also component. The measured optical dephasing times on the wavelength of the pump pulse is observed. At short correspond to homogeneous linewidths of 0.8-1.2 meV while population times T new bands appear at wavelengths around the period of the oscillation corresponds to an exciton 610 and 625 nm. The inset to Fig. 8 shows the evolution of binding energy of about 13 meV. The dependence of these the (normalised) echo intensity as a function of population quantities on the detection wavelength is associated with the time T for the detection wavelengths 610, 625 and 640 nm. difference in sizes of the quantum dots. ULTRAFAST LASER SPECTROSCOPY

Figure 10 (a) Femtosecond Ramsey interference arrangement. Figure 9 Three-pulse, two-colour (515, 530 nm) photon echo signal for CdTe quantum dots grown on ZnSe, recorded at 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 to Appl. Phys. Lett.

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

We are applying Ramsey’s separated oscillatory fields technique [1], commonly used in the microwave frequency 10 regime, to the optical frequency regime, using pairs of Figure 10 (b) Femtosecond Ramsey fringes for the Rb D1,2 lines. temporally-separated, phase-coherent femtosecond laser The 2.6 fs beat (in inset) corresponds to the optical pulses [2]. The first pulse generates optical coherence frequency (4x1014 Hz) and the 140 fs beat to the fine- between the excited and ground states of the atom (or structure splitting. molecule), inducing an oscillating optical dipole that continues to evolve freely in time decaying with a 1. N.F. Ramsey, Molecular Beams, Oxford Univ. Press (1956) characteristic dephasing time. The second (delayed) pulse 2. M. Bellini, A. Bartoli and T.W. Hänsch, Opt. Lett. 22, 540 (1997) interrogates the oscillating optical dipole, leading to interference fringes in the detected fluorescence with a period corresponding to that of the optical transition. In this ■ Femtosecond Laser Ablation way it is possible to observe the full cycle of an optical In conventional pulsed laser ablation, for example, using transition in real time as it actually evolves at optical nanosecond pulses from an excimer or Nd:YAG laser, the 15 frequencies of about 10 Hz. ablation mechanism is thermally driven, which can limit the precision of the micromachining, and the walls of a Femtosecond Ramsey interference techniques provide a machined hole often taper with increasing depth, limiting powerful high-resolution method that is yet to be exploited. achievable aspect ratios to about unity. The resolution is determined essentially by the time-delay between the two phase-coherent pulses, and is not limited In the case of femtosecond laser ablation the duration of the by the broad spectral bandwidth (~15 nm) of the pulse is short compared with the thermal conduction time femtosecond pulses. The Ramsey inference fringes contain and the characteristic relaxation times in the solid, and essentially all the spectroscopic information about the conventional thermal ablation is prohibited. In this case laser transition, including the fine and hyperfine structure of the ablation is believed to proceed via a non-thermal upper and lower levels, the rotational and vibrational electrostatic mechanism [1]. At the typical peak laser structure of the levels (in the case of molecules), the intensities available from a femtosecond regenerative dephasing time of the optical dipole, and the absolute amplifier (1013-1015 W cm-2) the laser energy absorbed by an frequency of the transition, which can be determined by electron through multi-photon processes exceeds the directly counting the optical cycles. ionisation potential and the energy required for the electron to escape the target, and the charge separation of the Figure 10b shows Ramsey interference fringes recorded for energetic electron and the parent ion creates a huge electric the rubidium D lines using an excitation wavelength of 1,2 field which removes the ions one by one, thereby allowing 787 nm. The phase-coherent pulses are generated in a high precision ‘non thermal’ micromachining. Michelson interferometer, which has a 20 cm variable delay line (1.3 ns) and step size down to 25 nm (0.2 fs) (Fig. 10a). 1. E.G. Gamaly, A.V. Rode, B. Luther-Davies and V.T. Tikhonchuk, Strong beat signals are observed at a period of 2.6 fs (inset Physics of Plasmas 9, 949 (2002) to Fig. 10b), corresponding to the frequency of the optical transition (4x1014 Hz), and at 140 fs (Fig. 10b), corresponding 2 2 12 to the fine-structure splitting 5 P3/2 – 5 P1/2 (7x10 Hz). ULTRAFAST LASER SPECTROSCOPY

Micromachining of Polymers Micromachining of Semiconductor Gallium Martin Lowe, Peter Hannaford (CAOUS) Nitride Films Erol Harvey (Industrial Research Institute Swinburne) Lap Van Dao, Martin Lowe Yanping Zhang, Akira Endo (Sumitomo Heavy Industries, Japan) Semiconductor films based on III-V nitrides, particularly GaN, are becoming increasingly important for the production of We are investigating femtosecond laser ablation of various new-generation blue diode lasers and blue light emitting polymers, including PMMA, PTFE and Polycarbonate, using diodes. Gallium nitride resists wet chemical etchants, and 100 fs laser pulses at 800 nm and pulse energies up to other methods need to be developed for machining the about 1 mJ. For beams focussed by a plano-convex lens, desired structures. Laser ablation, in principle, offers a direct high-quality, high aspect-ratio (>10) micromachining of holes and versatile means of surface modification without the need with diameters of 20-40 µm and depths of 300-400 µm has for chemical processes. However, attempts to ablate GaN been achieved (Fig. 11a) [1]. It appears that the hole formed with nanosecond pulses from Nd:YAG or excimer lasers have by the initial laser pulses acts as a fibre to couple the beam resulted in a layer of gallium being formed on the surface, of subsequent pulses into the bottom of the hole and due to thermal decomposition during the laser pulse. We are propagate the machining, thereby leading to holes with high investigating the ablation of thin GaN films using 100 fs aspect ratio. pulses at 800 nm. For fluences around 0.3 J cm-2 and pulse repetition rates of 1 kHz, regular channels of depth ≤1 µm have been successfully machined into GaN films on sapphire substrates.

Femtodentistry Andrei Rode, Eugene Gamaly, Barry Luther-Davies (Australian National University) Bronwyn Taylor, Judith Dawes (Macquarie University, Sydney) Ambrose Chan (Private Dental Practice, Caringbah, NSW ) 11 Martin Lowe, Peter Hannaford (CAOUS) Lasers offer the potential for painless, non-contact treatment of teeth in dentistry. The problems in applying conventional lasers for removal of hard dental tissues include poor surface preparation (cracking or fissures in the prepared surface), Figure 11 (a) Micromachined hole with high-aspect ratio in PMMA collateral (thermal) damage to the surrounding part of the using femtosecond laser ablation. tooth and especially the pulp, and slow removal rates (limited by the thermal load on the tooth) compared with those offered by the mechanical drill. The recent availability of femtosecond lasers with millijoule pulse energies and kilohertz 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 and the ANU Femtosecond Laser Source have been used to ablate dental enamel from extracted human teeth with very promising results [1]. The surface preparation of the teeth is excellent, as observed by optical and scanning electron microscopy: there is no visible cracking or fissures and the ablated surface is roughened which facilitates adhesion of filling material. The pulpal temperature, as measured by an Figure 11 (b) Array of microstrings formed in PMMA when using embedded thermocouple, shows rises of up to 100C over a projection patterning with a rectangular pinhole. 200 s treatment period. Flowing air over the tooth during 0 When using projection patterning with a rectangular pinhole, laser treatment reduces this rise to less than 5 C, which is regular arrays of micro-strings with diameters as small as below the pain limit. 2 µm and lengths greater than 10 mm are observed deep 1. A.V. Rode, E.G. Gamaly, B. Luther-Davies, B.T. Taylor, J. Dawes, within the bulk of the sample (Fig. 11b). This phenomenon is A. Chan, R.M. Lowe and P. Hannaford, J. Appl. Phys. (in press) attributed to effects of diffraction of the spatially coherent femtosecond laser beam by the rectangular hole and photopolymerisation by the diffracted self-focussing beams within the polymer sample.

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

■ Decoherence in Quantum Computation computation in terms of reducing the complexity of computation processes. However, quantum algorithms and Bryan Dalton, Tien Kieu all others discovered so far are only applicable to classically In the standard approach to quantum computation, the computable functions. There remains the class of classically fundamental building block is the quantum bit, or qubit. This noncomputable functions, such as in the halting problem for is a generalisation of the binary bit of classical computing, Turing machines [1]. It is widely believed that quantum but unlike the binary bit a qubit can be in a quantum computation does not result in any advances regarding superposition of its two states. Upon measurement the computability. Contrary to this belief, we propose a superposition is destroyed, revealing one of the two classical generalised quantum computation that may be able to values of the qubit. One of the key advantages that quantum compute the noncomputables. The idea is to encode the computers are expected to have over classical computers is solution of some problem to be solved into the ground state, in the area of computational complexity, (where complexity |g>, of some Hamiltonian, HP. As it is easier to implement here refers to the way computation time increases with the the Hamiltonian than to obtain the ground state, the size of the number being processed), an advantage based on computation is started in a different and readily obtainable features of quantum parallelism (superposition) and quantum initial ground state, |gI>, of some initial Hamiltonian, HI, and entanglement. In the quantum case the number of then this Hamiltonian is deformed into the Hamiltonian computational steps required to complete a calculation for whose ground state is the desired one. If the deformation certain algorithms is expected to increase much more slowly time is sufficiently long, the initial state will evolve with the size of the input numbers being processed than for adiabatically into the desired state with a high probability. classical computers, such as the exponential improvement in We have recently proposed a quantum algorithm for the the factorisation of integers (Shor’s algorithm). classically noncomputable Hilbert’s tenth problem [2], which However, the physical system whose quantum states define is ultimately linked to the halting problem for Turing the N qubit system embodying the registers of the quantum machines in the computation of partial recursive functions. computer is never completely isolated from the environment. If such a scheme can be realised, the notion of effective Similarly, the quantum devices involved in the gating computability is extended well beyond the Church-Turing processes that define the computational algorithm also thesis. To investigate the limitation of the quantum algorithm, 12 couple to the outside world. In general, the density operator we are also studying other problems [3] which belong to describing the state of the quantum computer does not further classes of noncomputable functions. remain pure and is changed by the system-environment 1. H. Rogers, Theory of Recursive Functions and Effective Computability interactions into a mixed state, with the coherences between (MIT Press, 1987) the different evolved input states being partially or completely destroyed. This process of decoherence is the 2. T.D. Kieu, submitted to Phys. Rev. A,http://xxx.lanl.gov/abs/quant- ph/0110136 (2001); submitted to Proc. Roy. Soc. Lond., enemy of quantum computation. http://xxx.lanl.gov/abs/quant-ph/0111063 (2001); submitted to Contemp. Phys., http://xxx.lanl.gov/abs/quant-ph/0203034 (2002) We are investigating the limits decoherence places on the implementation of practical quantum computers and how 3. T.D. Kieu, submitted to Quantum Information and Computation, decoherence rates scale with the number of qubits. A better http://xxx.lanl.gov/abs/quant-ph/0111062 (2001) understanding of scaling effects may lead to models for quantum computers that are less affected by decoherence. ■ Quantum Measurement Tien Kieu, Bryan Dalton

■ Quantum Adiabatic Computation The issue of quantum measurement is central to our Tien Kieu (CAOUS), Alan Head (CSIRO) understanding of quantum mechanics and plays a key role in the development of quantum algorithms. Quantum The general notion of computability has been defined in mechanics only offers a recipe for the outcomes of terms of the Church-Turing thesis with the introduction of the measurement, but not an explanation of the process [1]. idealised “universal Turing machine”. Turing was able to We have been one of the first to investigate this problem capture the essence of computation processes and using Quantum Field Theory (QFT) [2]. We are exploring the algorithms: What can be effectively computed is also use of the inequivalent unitary representations of QFT as a computable by Turing machines, and vice versa. If a function basis for describing the possible outcomes of a quantum cannot be computed at some given argument then the measurement. Such inequivalence is admissible here corresponding Turing machine cannot stop upon accepting because of the infinitely many degrees of freedom in QFT, the equivalent input. The famous Turing halting problem is but not in the standard quantum mechanics of systems with that it can be shown there exists no general way to determine fixed and finite numbers of particles. The description of the in advance whether a Turing machine, upon accepting some infinitely many degrees of freedom in macroscopic input, would eventually halt or continue on forever. For 70 measuring devices may be facilitated using this QFT years the Turing halting problem has occupied a central approach. position in Mathematics and Theoretical Computer Science and has set the limits of what is classically computable. 1. J. von Neumann, Mathematical Foundations of Quantum Mechanics (Princeton Univ. Press, 1955) Quantum computation based on qubits has recently been 2. M. Danos and T.D. Kieu, Int. J. Mod. Phys. E8, 257 (1999) shown to offer better performance over classical PUBLICATIONS

Research Publications 13. Unitary and quantum computation. 1. High-aspect ratio micromachining of polymers with T.D. Kieu, in Experimental Implementation of Quantum an ultrafast laser. Computation (ed. R.G. Clark), Rinton Press Inc., pp 348- Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and 351 (2001). A. Endo,Appl. Surface Sci. 186, 345-351 (2002). 14. Quantum principles and mathematical 2. Ultrafast laser spectroscopy of metalloporphyrins. computability. C.N. Lincoln, J.A. Bolger, R.M. Lowe, W.J. Rowlands and T.D. Kieu, Philosophica Mathematica (submitted). P. Hannaford, Proc. Sixth Int. Conf. on Optics Within Life 15. Doppler-free saturated absorption spectroscopy of Sciences (in press). natural lead in the near-ultraviolet. 3. Three-pulse two-colour photon echo and transient S. Bouazza, D.S. Gough, P. Hannaford, R.M. Lowe and grating studies of myoglobin. M. Wilson, Phys. Rev. A 63, 012516-012522 (2001). C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and 16. Micron-scale magnetic structures for atom optics.* P. Hannaford, Femtochemistry V (World Scientific, in press). A.I. Sidorov, R.J. McLean, B.A. Sexton, D.S. Gough, 4. Isotope shift studies in Zr I by Doppler-free T.J. Davis, A.M. Akulshin, G.I. Opat and P. Hannaford, saturated absorption spectroscopy and pseudo- Comptes Rendus de l’Academie des Sciences 2, relativistic Hartree-Fock calculations. I Transitions Series IV, 565-572 (2001). 3 2 4d 5s-4d 5s5p. 17. Hyperfine structure of odd-parity levels in 91Zr I. S. Bouazza, D.S. Gough, P. Hannaford, M. Wilson and S. Bouazza, D.S. Gough, P. Hannaford and M. Wilson, C. Lim, J. Phys. B 35, 651-662 (2002). J. Phys. B 33, 2355-2365 (2000). 5 Isotope shift studies in Zr I by Doppler-free 18. Sir Alan Walsh 1916-1998.* saturated absorption spectroscopy and pseudo- P. Hannaford, Hist. Rec. Aust. Sci. 13 (2), 45-72 (2000). relativistic Hartree-Fock calculations. II Transitions 4d25s2-4d25s5p. 19. Sir Alan Walsh 1916-1998.* S. Bouazza, D.S. Gough, P. Hannaford and M. Wilson, P. Hannaford, Biogr. Mem. Fell. R. Soc. Lond. 46, 533-564 J. Phys. B (in press). (2000). 13 6. Subpicosecond laser ablation of dental enamel. 20. Sub-Doppler laser cooling of fermionic 40K atoms. A.V. Rode, E.G. Gamaly, B. Luther-Davies, B.T. Taylor, G. Modugno, C. Benko, P. Hannaford, G. Roati and J. Dawes, A. Chan, R.M. Lowe and P. Hannaford, M. Inguscio, Phys. Rev. A 60,R3373-6 (1999). J. Appl. Phys. (in press). 21. Reflection of cold atoms from an array of current- 7. Femtosecond three-pulse photon echo and carrying conductors.* population grating studies of the optical properties D.C. Lau, A.I. Sidorov, G.I. Opat, R.J. McLean, of CdTe/ZnSe quantum dots. W.J. Rowlands and P. Hannaford, L.V. Dao, R.M. Lowe, P. Hannaford, H. Machino and T. Yao, Eur. Phys. J.D 5, 193-9 (1999). Appl. Phys. Lett. (submitted). 22. Magnetic mirrors with micron-scale periodicities for 8. Spectrally resolved two-colour three-pulse photon slowly moving neutral atoms.* echo studies of vibrational dynamics in molecules. D.C. Lau, R.J. McLean, A.I. Sidorov, D.S. Gough, L.V. Dao, C.N. Lincoln, R.M. Lowe and P. Hannaford, J. Koperski, W.J. Rowlands, B.A. Sexton, G.I. Opat and Physica B (submitted). P. Hannaford, J. Optics B: Quantum Semiclass. Opt. 1, 371-7 (1999). 9. A reformulation of the Hilbert’s tenth problem through quantum mechanics. 23. Magnetic atom optical elements for laser-cooled T.D. Kieu, Proc. Roy. Soc. Lond. (submitted), atoms.* http://xxx.lanl.gov/abs/quant-ph/0111063 (2001). D.C. Lau, R.J. McLean, A.I. Sidorov, D.S. Gough, J. Koperski, W.J. Rowlands, B.A. Sexton, G.I. Opat and 10. Quantum algorithm for the Hilbert’s tenth problem. P. Hannaford, J. Kor. Phys. Soc. 35, 127-32 (1999). T.D. Kieu, Phys. Rev. A (submitted), http://xxx.lanl.gov/abs/quant-ph/0110136 (2001). 24. Atomic absorption with ultracold atoms.* P. Hannaford and R.J. McLean, 11. Hilbert’s incompleteness, Chaitin’s Ω number and Spectrochim. Acta,Part B 54, 2183-94 (1999). quantum physics. T.D. Kieu, Quantum Information and Computation 25. The oscillator strength in atomic absorption (submitted), http://xxx.lanl.gov/abs/quant-ph/0111062 spectroscopy.* (2001). P. Hannaford, Microchem. J. 63, 42-52 (1999). 12. Computing the noncomputables. 26. A magneto-optically recorded mirror for cold atoms.* T.D. Kieu, Contemp. Phys. (submitted), D.S. Gough, R.J. McLean, A.I. Sidorov, D.C. Lau, http://xxx.lanl.gov/abs/quant-ph/0203034 (2002). J. Koperski, W.J. Rowlands, B.A. Sexton and P. Hannaford In Laser Spectroscopy (eds. R. Blatt et al), World Scientific, Singapore, pp 340-1 (1999). PUBLICATIONS

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 absorption spectrophotometer. P. Hannaford, The Physicist 38, 41-48 (2001). 3. Report on the Fifteenth International Conference on Laser Spectroscopy. P. Hannaford, Aust. Opt. Soc. News 15, 19-23 (2001). 4. “The storage of light” and very large variations of the group velocity of light in coherently prepared atomic 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.

14 CONFERENCES

Conferences 12. Permanent magnetic microstructures in integrated atom International Conference on Experimental optics. Implementation of Quantum Computation A.I. Sidorov,T.J. Davis, R.J. McLean, D.S. Gough, Sydney, Australia, 16-19 January 2001. P. Hannaford and G.I. Opat.

1. Unitarity constraints in quantum computing. 13. Femtosecond Ramsey interference spectroscopy. T.D. Kieu. R.M. Lowe, L.V. Dao, C.N. Lincoln, W.J. Rowlands and P. Hannaford. 15th International Conference on Laser Spectroscopy Snowbird, USA, 11-15 June 2001. 14. Quantum computation and mathematical decidability. T.D. Kieu. 2. A high-quality, micron periodicity, grooved magnetic mirror for atom optics. 15. Ultrafast spectroscopy using ultracold molecules. A.I. Sidorov, R.J. McLean, B.A. Sexton, T.J. Davis, H. Kitson and W.J. Rowlands. D.S. Gough, P. Hannaford,A.M. Akulshin and G.I. Opat. Workshop on Truths and Proofs Femtochemistry V Auckland, New Zealand 7-8 December 2001. Toledo, Spain, 2-6 September 2001. 16. Quantum principles and mathematical computability. 3. Three-pulse two-colour photon echo and transient grating (Invited Talk). studies of myoglobin. T.D. Kieu. C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and Bose-Einstein Condensation Workshop P. Hannaford. Kioloa, Australia, 30 January-3 February 2000. Multi-Dimensional Microscopy 2001 17. Sub-Doppler laser cooling of fermionic 40K. Melbourne, 25-28 November 2001. G. Modugno, C. Benko, P. Hannaford,G.Roati and 4. Femtosecond coherence spectroscopy (Invited Talk). M. Inguscio. C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and Sixth International Conference on Optics Within Life P. Hannaford. 15 Sciences Australasian Conference on Optics, Lasers and Sydney, 22-24 February 2000. Spectroscopy 18. Ultrafast laser spectroscopy of metalloporphyrins. Brisbane 3-6 Dec, 2001. C.N. Lincoln, J.A. Bolger, R.M. Lowe, W.J. Rowlands and 5. Light propagation in nonlinear media with very steep P. Hannaford. dispersion. Seventeenth International Conference on Atomic A.M. Akulshin,A.Cimmino, B. Cantwell, P. Hannaford, Physics R.J. McLean, A.I. Sidorov, and G.I. Opat. Florence, Italy, 4-9 June 2000. 6. High-quality, micron-scale, grooved magnetic mirrors for 19. Microfabricated magnetic structures for cold atom optics. atom optics. D.S. Gough, R.J. McLean,A.I. Sidorov, T.J. Davis, R.J. McLean,A.I. Sidorov, D.S. Gough, F. Scharnberg, B.A. Sexton, P. Hannaford and G.I. Opat. B.A. Sexton, T.J. Davis, A.M. Akulshin, G.I. Opat and P. Hannaford. First International Symposium on Laser Precision Microfabrication, 7. Femtosecond coherence spectroscopy of the Omiya, Saitama, Japan, 15-16 June, 2000. photodissociation of MbCO. C.N. Lincoln, L.V. Dao, R.M. Lowe, W.J. Rowlands and 20. Formation of a micro-string array in transparent P. Hannaford. materials exposed to a beam of 100 fs laser pulses. Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and 8. Spectral analysis of 2-colour 3-pulse photon echoes on a A. Endo. femtosecond time scale. D.V. Dao, C.N. Lincoln, R.M. Lowe, W.J. Rowlands and Workshop on Recent Progress with Trapped Ions and P. Hannaford. Atoms, 9. Subpicosecond laser ablation of dental enamel. Innsbruck, 16 June 2000. A.V. Rode, E.G. Gamaly, B. Luther-Davies, B.T. Taylor, 21. Micron-scale magnetic structures for atom optics J. Dawes, A. Chan, R.M. Lowe and P. Hannaford. (Invited Talk). 10. Micro-machining of GaN films by ultrafast laser ablation. P. Hannaford, D.S. Gough, R.J. McLean, A.I. Sidorov, L.V. Dao, R.M. Lowe and P. Hannaford. T.J. Davis, B.A. Sexton and G.I. Opat.

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

Sixth International Workshop on Atom Optics and Fourth International Conference on Laser Spectroscopy, Interferometry Innsbruck, Austria, 7-11 June, 1999. Cargese, Corsica 26-29 July, 2000. 31. A magneto-optically recorded mirror for cold atoms. 22. Micron-scale magnetic structures for atom optics D.S. Gough, R.J. McLean, A.I. Sidorov, D.C. Lau, (Invited Talk). J. Koperski, W.J. Rowlands, B.A. Sexton, P. Hannaford A.I. Sidorov, R.J. McLean, B.A. Sexton, D.S. Gough, and G.I. Opat T.J. Davis, A. Akulshin, G.I. Opat and P. Hannaford. Twelfth Conference of the Australian Optical Society, 23. Ultracold collisions of fermionic potassium in an optical Sydney, Australia, 4-9 July, 1999. dipole trap. G. Modugno, G. Roati, P. Hannaford and M. Inguscio. 32. Matter-wave optics in Melbourne (Invited Talk). P. Hannaford Tenth International Conference on Non-Resonant Laser-Matter Interaction St. Petersburg, Russia, 21-23 August 2000.

24. Micro-string arrays formed in transparent materials under 100-fs laser pulses. Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo. Fall Meeting of the Japanese Applied Physics Society Sapporo, Hokkaido, Japan, 2-6 September, 2000.

25. Formation of a micro-string array in transparent materials with a femtosecond laser beam. Y. Zhang, R.M. Lowe, E.C. Harvey, P. Hannaford and A. Endo. 16 XI European Conference on Quantum Optics Mallorca, 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 Society Adelaide, 12-15 December 2000.

27. Specular reflection of ultracold atoms from microfabricated 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 and P. Hannaford.

29. Interaction of ultrashort laser pulses with transparent polymers. R.M. Lowe,Y.Zhang, E.C. Harvey and P. Hannaford. Fifth International Conference on Atom Optics and Atom Interferometry 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 SEMINARS AND MEDIA PRESENTATIONS

Seminars Media Presentations 1. Atom Optics at Swinburne. 1. New Scientist: R.J. McLean, The University of Melbourne, 27 April 2001. “Smash and grab”. Computing the noncomputables. Review by Chown Marcus, 2. Quantum computing: information processed through the 6 April 2002. principles of quantum mechanics. T.D. Kieu, Swinburne University of Technology, 2. The ABC Quantum program: 18 May 2001. The Swinburne Femtosecond Laser Facility. Presented by Paul Willis, 3. Magnetic optics for slowly moving atoms. 22 May 2000. P. Hannaford, Stanford University, USA, 8 June 2001. 3. The ABC Science Show: 4. The laser spectroscopy program at Swinburne University Professor Ahmed Zewail and the Swinburne of Technology. Femtosecond Laser Facility. P. Hannaford, University of Queensland, 10 July 2001. Presented by Robyn Williams, 5. Photoluminescence studies of semiconductor 27 February 1999. nanostructures. 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 of decidability/computability. T.D. Kieu, The University of Melbourne, 10 October 2001. 17 8. Can quantum computing resolve the Turing halting problem? T.D. Kieu, Swinburne University of Technology, 19 October 2001.

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

10. The 2001 Nobel Prize in Physics. P. Hannaford and W.J. Rowlands, The Australian Institute of 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 Atom Optics, 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 moving atoms. P. Hannaford, European Laboratory for Nonlinear Spectroscopy, Florence, 23 March 1999.

15. Microfabricated magnetic optics for slowly moving atoms. P. Hannaford, University of Pisa, Italy, 17 March 1999. COMPETITIVE GRANTS AND COLLABORATIONS

Competitive Grants International Collaborations 1. ARC Discovery Grant (2002 $72,000; 2003 $100,000; European Laboratory for Nonlinear Spectroscopy (LENS), 2004 $31,000). Florence, Italy (Prof Massimo Inguscio, Dr Giovanni Modugno) A.I. Sidorov, P. Hannaford, R.J. McLean, G.I. Opat, T.J. Davis. Massachusetts Institute of Technology, Cambridge, USA Integrated atom optics: guiding matter waves with (Dr Edward Farhi) magnetic microstructures. Nanyang Technological University, Singapore (Prof Shu Yuan) 2. ARC Discovery Grant (2002 $70,000). W.J. Rowlands. North Eastern University, Boston, USA (Dr Sam Gutmann) Generation and application of ultracold molecules. Sumitomo Heavy Industries, Japan (Dr Yanping Zhang) 3. ARC Linkage Infrastructure Grant (2002 $530,000). The Femtosecond Technology Research Association, A.N. Luiten (UWA), D.D. Sampson (UWA), P. Hannaford Japan (Dr Akira Endo) (CAOUS), D.M. Kane (Macquarie). A transportable optical frequency counter, synthesiser Tohoku University, Sendai, Japan (Prof Takafumi Yao, and super-continuum generator. Dr Hisao Makino) 4. ARC Research Development Grant (2002 $8,000). Tulane University, New Orleans, USA (Dr Mike Wilson) T.D. Kieu. Quantum computation. University of Reims, France (Dr Safa Bouazza) 5. Systemic Infrastructure Initiative Grant (2002 $1,674,000; 2003 $151,000; 2004 $151,000). National Collaborations P. Hannaford (CAOUS), A. Mazzolini (CIAO), E.C. Harvey Australian National University, Canberra (Dr Andrei Rode, (IRIS), M. Gu (CMP), M.W. Austin (RMIT University). Dr Eugene Gamaly, Prof Barry Luther-Davies) Integrated microfabrication facility. CSIRO Manufacturing Science and Technology, Melbourne 6. ARC Research Infrastructure Equipment and Facilities 18 (Dr Tim Davis, Dr Brett Sexton, Prof Alan Head) (RIEF) Grant (2001 $480,000). K. P. Ghiggino (Univ. Melb.), T.A. Smith (Univ. Melb.), Industrial Research Institute Swinburne (IRIS), Melbourne P. Hannaford (CAOUS), W.J. Rowlands (CAOUS), (Dr Erol Harvey) M. Gu (CMP), X. Gan (CMP). Ultrafast microspectroscopy facility. Royal Melbourne Hospital (Dr Andrew Rawlinson)

7. ARC Small Grant (2000 $15,000). RMIT University (Dr Arnam Mitchell, Prof Mike Austin) E.C. Harvey and P. Hannaford. Ultra-short pulsed laser ablation for micromachining. 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) VISITING POSITIONS, HONOURS AND AWARDS

Visiting Positions, Honours and Awards Lap Van Dao Australian Academy of Science Exchange Fellowship, Tohoku University, Sendai, Japan (October 2001)

Peter Hannaford Elsevier Spectrochimica Acta Atomic Spectroscopy Award (2001)

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

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

Tien Kieu Visiting 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 Lincoln IAESTE Exchange Studentship, University of Vienna, Austria (August-September 2001)

Russell McLean 19 Elsevier Spectrochimica Acta Atomic Spectroscopy Award (2001)

Geoffrey Opat Order of Australia (2002) Further information Centre for Atom Optics and Ultrafast Spectroscopy (CAOUS) School of Biophysical Sciences and Electrical Engineering Swnburne University of Technology John Street Hawthorn Victoria Australia 3122 Telephone: +61 3 9214 5164 Facsimile: +61 3 9214 5840 Web: www.swin.edu.au/lasers/caous