************************************ * QUANTUM OPTICS AND ATOM OPTICS * * IN AUSTRALASIA * * * * * * * * MONTHLY NEWSLETTER * * VOL IV, NO 9 * * * CONTENTS: * September 1996 * ________________ * * * ISSN 1325-6467 * 1. ABSTRACTS * * Edited by: Craig Savage 2. CONFERENCE * \ | / * Physics, Faculties, ANU, 3. JOB * \__|__/ * ACT 0200, Australia. 4. NOTICE * | * email: Craig.Savage@anu.edu.au Available on WWW at: * | * fax: +61 [(0)6] 249 0741 http://www.anu.edu.au * | * voice: +61 [(0)6] 249 4202 /Physics/newsletter * * ___________________ Please send in abstracts for the next newsletter. I am particularly interested in abstracts of preprints, whether or not accepted for publication. ___________________ 1. ABSTRACTS ____________ TITLE: Transfer Function Approach to Collective Mode Dynamics in a Nd:YAG Laser AUTHORS: L Stamatescu and M W Hamilton ADDRESS: Department of Physics and Mathematical Physics, University of Adelaide, Adelaide SA 5005, Australia EMAIL: mwh@physics.adelaide.edu.au JOURNAL: Phys. Rev. Letts. STATUS: submitted ABSTRACT: For a multimode laser operating in a steady state regime with small-signal gain modulation, transfer functions are measured for both total intensity and intensities of individual modes. A quantitative picture of the phase clustering of contributions from each cavity mode to the collective mode dynamics is obtained and a corresponding theoretical analysis is presented. ____________ TITLE: Study of threshold-like transition in the microlaser using quantum trajectory simulations AUTHOR: Changhuei Yang and Kyungwon An ADDRESS: G. R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139 EMAIL: kwan@mit.edu JOURNAL: Physical Review A STATUS: Submitted ABSTRACT: In the recent microlaser experiment [K. An et al, Phys. Rev. Lett. {\bf 73}, 3375 (1994)], a threshold-like transition of intracavity mean photon number as a function of intracavity mean atom number has been observed. In this paper, the underlying physics is explored with quantum trajectory simulations. It is shown that the transition is caused by enhanced atom-cavity Rabi interaction due to the increase of the intracavity photon number as the intracavity atom number is increased. The transition is further accentuated by the position dependent variation of the coupling constant in the Fabry-Perot cavity. In addition, it is demonstrated that multiatom collective effects are negligible in the microlaser under consideration, in which atoms are injected into the cavity at random times and the product of the coupling constant and atom-cavity interaction time is much less than $\pi$. In this case the analytic theory of one-atom micromaser [Filipowicz et al, Phys. Rev. A {\bf 34}, 3077 (1986)] can be extrapolated into the multiatom region, assuming uniform atom-cavity coupling throughout the cavity and monovelocity atomic injection. Finally, fully realistic simulations are performed, accounting for spatial variation of coupling constant, velocity distribution of injected atoms, and spontaneous atomic decay in the actual experiment. The results are in good agreement with experiment. ____________ TITLE: Dynamical identification of open quantum systems AUTHOR: H. Mabuchi ADDRESS: Norman Bridge Laboratory of Physics California Institute of Technology 12-33, CA 91125 EMAIL: hmabuchi@cco.caltech.edu JOURNAL: Quantum Semiclass. Optics (JEOS B) STATUS: Accepted ABSTRACT: I propose a quantum trajectories approach to parametric identification of the effective Hamiltonian for a Markovian open quantum system, and discuss an application motivated by recent experiments in cavity quantum electrodynamics. This example illustrates a strategy for quantum parameter estimation that efficiently utilizes the information carried by correlations between measurements distributed in time. &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 2. CONFERENCE ____________ REPORT on the WORKSHOP ON ATOM OPTICS Cairns, June 9 - 11, 1996 by Dr. Ken Baldwin The field of Atom Optics - the manipulation of the atomic de Broglie wave in analagous fashion to light optics - has grown rapidly in recent years. The strength of interest in the field was apparent at this international workshop held in Cairns from 9 - 11 June as a satellite meeting to the major International Quantum Electronics Conference (IQEC '96) in Sydney from 14 - 19 June. Nearly 160 scientists from 20 countries attended the Cairns workshop, which was run back-to-back with a meeting on Quantum Optics at the same venue (June 8 - 9). Together these workshops provided the backbone for the attendance at IQEC '96 (with around 700 registrants). The attendance is even more remarkable given that a major European workshop on Atom Optics was held in Italy just one month beforehand, attracting over 100 registrants of whom 30 or so later attended the Australian meeting. The Australasian contingent reflected the strength of the field in this part of the world, contributing over 50 of the delegates in Cairns. In all, 6 papers by invited speakers, 15 contributed talks and 55 contributed posters were presented over the 3 days of the workshop. This high level of interest reflects the rapid progress and diversification in the field. A highlight of achievement in physics in recent times has been the laser cooling of atoms to nanokelvin temperatures to produce the first Bose-Einstein Condensate (BEC). This was a major theme of the conference which was attendedby Eric Cornell from the first group to achieve BEC in Boulder, Colorado. The first experiments on the physics of the condensate have now been performed, with the measurement of vibrational modes of this macroscopic quantum state. Significant advances have also been made in atom interferometry which has been used to very sensitively measure fundamental quantites. For example, Steven Chu of Stanford University reported on precision measurements of the fractional change in little g which has the potential to surpass conventional gravimeters in sensitivity. Still others reported progress on other atom optical components, such as mirrors based on magnetic fields (Maclean from Melbourne and Wynands from Bonn) and evanescent light waves (Aspect from Paris). Hollow optical fibres which use evanescent light fields to guide the atoms through the fibre were also reported by the Boulder group (Cornell) and the Seoul/Tokyo collaboration (Jhe). Applications of atom optics are now being actively pursued, particularly in atom lithography. Using a hologram made from coded apertures in a SiN membrane, the interference pattern produced by the de Broglie waves of cold neon atoms was used to write structures with sub - 100 micron resolution (Shimizu, Tokyo). Even greater resolution can be obtained using mask lithography of photoresists which are exposed to energetic metastable rare gas atoms, with edge structures as small as 30 nm being reported in Konstanz (Mlynek) and Harvard (Johnson). A special session was devoted to the comparison of other matter wave optics techniques. The state of the art in neutron interferometry was reported from a number of perspectives (Klein, Melbourne; Werner, Missouri; and Zeilinger, Innsbruck). Comparisons were also made with interferometry using charged particles (Hasselbach, Tubingen). There was clearly something to be learnt from all forms of particle optics, with the maturer fields pointing the way to future directions for the unique properties of atom optics, with its ability to control both the internal state and momentum of the atom. The future of atom optics was also the subject of a panel discussion for the final session of the conference. There was a sense that although atom optics was a fascinating field with some beautiful demonstration of principles through the ability to directly reproduce and extend light optics, there was a need for the field to put something back into the rest of science through useful applications. Many ideas were put forward, including lithography for nanostructure fabrication, interferometry for the measurement of gravity fields for mineral exploration, and atom tweezers for biological applications. However, recent progress in BEC might indicate that perhaps the most potent tool may be the equivalent of the laser which was given to science by optics - the production of a coherent source of amplified atomic de Broglie waves - or an atom "laser". A Special Issue on Atom Optics including many of the advances presented at the Elba and Cairns conferences has been published in "Quantum and Semiclassical Optics" (Journal of the European Optical Society Vol. 8, No. 3). Copies of the Special Issue may be obtained from Prof. Hans Bachor, Physics Department, Faculty of Science, The Australian National University, Canberra ACT 0200: Tel (61) 6 249 2747, Fax (61) 6 249 0741; email: hans.bachor@anu.edu.au &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 3. JOB ____________ THE AUSTRALIAN NATIONAL UNIVERSITY Canberra ACT 0200 Australia FACULTY OF SCIENCE DEPARTMENT OF PHYSICS AND THEORETICAL PHYSICS Lecturer (Level B) (RENEWABLE FIXED-TERM) Closing date: 2 October 1996 The Department seeks to appoint a Level B academic to support its teaching and research activities. The successful applicant will be part of an enthusiastic team of academics who provide a complete undergraduate and graduate teaching program in experimental, theoretical and computational physics for scientists and engineers. We are seeking to employ a staff member with talent for both undergraduate and postgraduate teaching and a commitment to encourage female students in the study of physics. For full details including selection criteria see the web page: http://online.anu.edu.au/Physics/job_dept.html &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 4. NOTICE ____________ To all Members of the Optical Society of America About now is the time for OSA elections, and most members will have received a ballot paper. From my experience, most Australasian members usually just discard this, but I'd urge you this time around to take a closer look. This year's selection of candidates is a bit more international than usual, and contains one nominee in particular who points out that OSA's membership from non-US members constitutes about 1/3 of the total, and who promises to promote the international activites of OSA. The other candidates this year are also of a very high calibre, and have interesting statements of objectives. Without wanting to prejudice anyone's opinions, could I please just draw your attention to this year's elections, and encourage all OSA members to participate. If you have already discarded your ballot paper, the deadline in 30 Sept so there's enough time to contact OSA (http://www.osa.org) for another. John Dudley University of Auckland &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&