Bigelow says the unusual partnership has enabled his lab to make several breakthroughs over the last few years. For instance, in keeping with the Bigelow group's focus on supercooled mixes of atoms of different elements, the team developed a theory to explain what a double Bose condensate, one combining two such species, might look like. Their prediction, that the double condensate would separate into layers much like the white and yolk of an egg, was borne out by subsequent experiments at other institutions.
Bigelow attributes such successes to the unbeatable combination of strong experiments backed by top-notch theoretical creativity.
"So often in physics, theorists and experimentalists are completely isolated, even if they're working toward the same goal," he says, noting that the chasm between theory and experiment is so great in some disciplines, particle physics, for instance, that an entire discipline -- phenomenology -- has developed to bridge the gap. "Most frequently you end up with the theory way ahead of the experiments, as in particle physics, or with the theorists lagging the experimentalists, like we've seen in high-temperature superconductivity."
But Law's participation in Bigelow's research has served to keep theory and experiment in lockstep. "In the world of supercold atoms, most research groups are somewhat like explorers, plowing ahead without entirely knowing where they're headed," says Bigelow. "But having a strong theoretical framework for our experiments has given our lab a very valuable edge."
The collaboration between Bigelow and Law, a postdoctoral researcher, began in 1995, shortly after the first Bose-Einstein condensate was observed. Law, intrigued by the news even though it was outside his area of specialty, approached Bigelow to learn more about it. When they got to discussing the theoretical equations underpinning Bose-Einstein condensates, Law began to see similarities between his own area of expertise -- the structure and behavior of photons -- and waves generated by Bose-Einstein condensates. "If we view Bose-Einstein condensates as a source of coherent matter waves," he says, "then training in quantum optics can come in handy."
"My research is aimed at finding ways of sending more and more bits over the same fiber!" Agrawal says. It is easy to understand that this research is watched with more than casual interest by a wide range of companies in the optics industry.
Agrawal's students find science-related jobs in various areas of optics, working as communication engineers, optical communication specialists and lightwave system designers. For example, a recent Ph.D. graduate, Joanne Law, who finished an RTC thesis project under Agrawal, is working at Therma-Wave Corporation, using her expertise in semiconductor lasers to improve the inspection of silicon chips. Other companies where students have taken position include Corning and Bell Labs (Lucent Technologies). Laboratories of mission-oriented federal agencies, for example, Los Alamos National Laboratory and Naval Research Laboratory, are also appropriate employment sites.
Another of Agrawal's RTC students, Drew Maywar, recently won a National Science Foundation Fellowship to continue his work on optical switching using semiconductor devices at the University of Tokyo.
Agrawal is currently interested in problems specifically associated with the distributed amplification of solitons (solitary waves) in optical fibers. He expects this research to benefit greatly from the formation of an RTC research team including grad student Zhi Lao and a new RTC postdoc, Taras Lakoba.
Dr. Lakoba was working on nonlinear mathematical physics for his Ph.D. degree, and has already considered some elements of soliton propagation, so distributed amplication theory provides a very appropriate first challenge for him in his RTC postdoctoral environment. Practical engineering elements will be important, and it would not be unusual if he will learn from Zhi Liao as well as vice versa.
The research being done focuses on distributed amplification of solitons, a scheme in which soliton sare amplified continuously all along the fiber, making it possible to maintain the soliton energy in a distributed sense. Agrawal expects Lakoba to begin by studying means to counteract the effects of chromatic dispersion by using nonlinear effects in the fiber.
Research on optical communications is well-established, both in academia and in industry, and this is expected to be true well into the future, as frontiers are being driven rapidly forward. The reason is clear, as Agrawal says, "Fibers can preserve information more accurately, and using fiber optics allows for the transport of a greater number of signals all at the same time."
Dr. Sascha Wallentowitz completed his Ph.D. thesis work in January this year, as a member of the quantum optics group of Prof. Werner Vogel in the University of Rostock. His thesis research dealt with the theory of methods for preparing and determining non-classical states of a trapped ion. While an undergraduate, had occasion to work with Profs. Wolfgang Schleich and the late Hannes Risken, participating in the long-established quantum optics program at the University of Ulm.
This is far from a one-man project, as Stroud has been working with a research team of students and an RTC post-doc, Dr. Paolo Bellomo. The theme of their project is to learn more efficient ways to store information inside an atom by detailed manipulation of the electrons in the atom. Originally about one ten- billionth of a meter in size, an atom can be inflated, almost like a balloon, with laser light to become perhaps 2500 times larger.
This increase in size, associated with a drastic change in the atom's quantum mechanical wave function, makes it possible in principle to imprint a large quantity of information in the wave function. If this information is stored in the atom, and the inherently parallel propagation of the quantum wave function is used to manipulate the information, a quantum computer might be constructed. Such a system would enormously enhance the future capabilities of computers.
Although it isn't anyone's immediate purpose in Stroud's group to design computers that would be directly suitable for exploitation in industrial labs, (much less home offices) the combination of experimental and theoretical practice that they typically get makes them good targets for recruiters. For example, RTC student Jim West, who worked with Stroud on Rydberg states of two-electron atoms, is currently employed at Corning, Inc. in optical communication research. His group leader is another Stroud student, Karl Koch, and yet another earlier student, Zagorka Dacic Gaeta, also works there. Mike Van Leuween, a former RTC student with Stroud, is also working on optical communication at the University of Maryland.
Stroud estimates that 75% of his students go into industry. This is due to industry's backlog of demand for first rate students with the most up to date comprehensive knowledge of optics. "Students who go out into industry can see where their learning can be applied," Stroud said, explaining that those who understand the fundamentals of physics and are learning state of the art concepts in school can look forward to many possible ways in which to apply their knowledge after they graduate. For example, a former student, Stephanos Papademetriou, currently working in industry, expanded his knowledge of the principles of the interaction of a modulated laser beam with atoms to create an instrument used to measure temperature in a medical procedure for prostate surgery. The idea, born during his years as a student, was carried over and was able to be applied outside the world of academia.
J.H. Eberly, "Area Theorem rederived," Optics Exp. 2, 173 (1998).
W.-C. Liu and M. W. Kowarz, "Vector diffraction from subwavelength optical disk structures: Two-dimensional near-field profiles," Optics Exp. 2, 191 (1998).
B. Kneer and C.K. Law, "Preparation of arbitrary entangled quantum states of a trapped ion," Phys. Rev. A 57, 2096 (1998).
M. Kalinski, "Aharonov-Bohm oscillations in a hydrogen atom in a radiation field through electron self-interference," Phys. Rev. A 57, 2239 (1998).
Philip D. Laible, Robert S. Knox and Thomas G. Owens, "Detailed Balance in Forster-Dexter Excitation Transfer and Its Application to Photosynthesis," J. Phys. Chem. B 102, 1641-1648 (1998).
H. Pu and N.P. Bigelow, "Collective Excitations, Metastability, and Nonlinear Response of a Trapped Two-Species Bose-Einstein Condensate," Phys. Rev. Lett. 80, 1134 (1998).
R. Ejnisman, H. Pu, Y.E. Young, N.P. Bigelow and C. K. Law, "Studies of two-species Bose-Einstein condensation", Optics Exp. 2, 330 (1998).
C.K. Law and J.H. Eberly, "Synthesis of arbitrary superposition of Zeeman states in an atom," Optics Exp. 2, 368 (1998).
M. Berry, J. T. Foley, G. Gbur and E. Wolf, "Nonpropagating string excitations," Am. J. Phys. 66, 121 (1998).
T. Shirai, E. Wolf, H. Chen and W. Wang, "Coherence filters and their uses II. One-dimensional realizations," J. Mod. Opt. 45, 799 (1998).
J.H. Eberly and C.K. Law, "Classical Control of Quantized Fields: Cavity QED and the Photon Pistol," Acta Phys. Polonica A 93, 55 (1998).
C.K. Law, H. Pu, N.P. Bigelow and J.H. Eberly, "Quantum phase diffusion of a two-component dilute Bose-Einstein condensate," Phys. Rev. A 58, 531 (1998).
Paolo Bellomo and C.R. Stroud, Jr., "Dispersion of KulauderŐs temporally stable coherent states for the hydrogen atom," J. Phys. A. Math. Gen. 31, L445 (1998).
Jake Bromage, Stojan Radic, G.P. Agrawal, and C.R. Stroud, Jr., P.M. Fauchet and Roman Sobolewski," Spatiotemporal shaping of half-cycle terahertz pulses by diffraction through conductive apertures of finite thickness," J. Opt. Soc. Am. B 15, 1953 (1998).
Ashiqur Rahman and J.H. Eberly, "Theory of shape-preserving short pulses in inhomogeneously broadened three-level media," Phys. Rev. A 58, R805 (1998).
"The Cross-Phase Modulation between Two Intense Orthogonally Polarized Laser Beams Co-Propagating through a Kerr-like Medium," John Marozas, RTC.
"Multicomponent pulses in laser systems," Nail Akhmediev, Optical Sciences Center, Australian National University.
"A Hermite-Gaussian expansion for pulse propagation in strongly dispersion-managed fibers," Taras Lakoba, Clarkson University.
"Single and multiple scattering by size-shape mixtures of small nonspherical particles," Michael Schulz, University of Alaska, Fairbanks.
"The Focusing of Light," and "Wave Propagation in Semiconductor Amplifiers," Tako Visser, RTC Visiting Fellow, Free University of Amsterdam Netherlands.
"A Parametric Amplifier for Atomic Matter Waves," C.K. Law, RTC.
"Interference-induced trapping states in the motion of a trapped atom," Sascha Wallentowitz, Rostock, Germany.
RTC Report:
Edited by Karen Burkin
newsletter@pas.rochester.edu
Mailing Address:
Rochester Theory Center for Optical Science and Engineering
University of Rochester, P.O. Box 270171
Rochester, NY 14627-0171, USA
Phone: (716) 275-3288