This is the unusual story of an unexpected reversal of the accepted norm. In this case there has been academic payoff from industrial research, instead of the reverse. The payoff became possible just as Dr. Liu was finishing work on an off-site RTC assignment in the Kodak Research Labs, and learned of the research project of Prof. Houde-Walter on campus. She is leading a group of scientists working in collaboration with the National Institute of Standards and Technology (NIST) at Boulder, Colo., studying new optical materials designed for applications such as tiny lasers that will play a role in telecommunications. Her group is experimenting with wave guide fabrication, learning how to trap and channel a compact source of light delivered via optical fibers. This research illuminates the interdisciplinary theme of many RTC projects. It pulls together people with different kinds of expertise to focus on a common goal, and Liu's contribution has been highly valued. "He's playing a very important role in helping us interface with NIST, and also helping us in modeling devices and materials," Houde-Walter says. Liu's role in the collaboration is to analyze and refine the overall controlling code developed at NIST, creating new mathematical models that enable Houde-Walter's team to design better wave guides that carry light more efficiently.
Previously, while working at Kodak on optical data storage, Liu developed numerical methods to calculate diffraction from sub-wavelength-sized structures in two and three dimensions. He designed new numerical algorithms for directly solving the time dependent Maxwell equations efficiently in full vector form, taking full account of dielectric layering and complex dielectric indices. Although these new techniques were applied differently at Kodak (and a number of publications have already resulted from that), Liu knew that the same physics governs light propagation through a complex loaded waveguide.
There are complications not found in the optical disk project because the waveguide material is active rather than passive. Liu must both solve the boundary value problem presented by Maxwell's equations, modeling accurately the waveguide properties, and then determine the material feedback, which is provided by the appropriate laser rate equation. He uses his numerical code to optimize the predicted output of the laser by iteration.
Liu works closely with Houde-Walter and her students at the Institute of Optics. They are able to work in an efficient near-symbiotic way, where Liu uses experimental results to improve the theoretical predictions, and the experimentalists can use his predictions to refine the experimental approach.
Speakers and participants are expected from European as well as U.S. and Canadian institutions. In addition to lectures, the workshop will feature tutorials, contributed papers, moderated topical discussions, and a poster session.
The workshop will focus on coherent processes induced or controlled by laser radiation. Key topics will be coherent control of dynamics in complex environments and extended systems, including control of quantum entanglement, control of dynamics in molecules and coherence in quantum semiconductor structures. Novel strong-field phenomena and ultrafast dynamics in large systems will also be convered.
The workshop is organized by M. Ivanov, P. Corkum, A. Stolow (NRC), and I. Walmsley (University of Rochester). To attend, contact Dr. Ivanov by e-mail: misha.ivanov@nrc.ca, or by phone: (613) 993-9973, or fax: (613) 991-3437). Housing will be available at the Citadel Inn/Crown Plaza Hotel, (613) 237-3600. There is no registration fee. The deadline for paper submission and hotel reservation is April 20.
Although Hall's focus has stayed just ahead of industrial application, experimental components have always been a part of his group's work. "My students and postdocs have engaged in .... sample preparation and characterization, optical and other measurements in the laboratory..." he said. Optical industry certainly sees the value of this, as demonstrated by their enthusiasm for researchers under Dr. Hall's supervision. His most recent Ph.D. students have taken positions with such leading companies as Lucent, IBM, OCLI, and Corning.
Hall's work has contributed to current understanding of optical phenomena in small-scale, solid structures. For him, a 'small' structure is on the order of the wavelength of light or smaller, around 0.5 microns in height or width, while a human hair is 'huge', 50 to 100 microns in diameter. Solid structures are appropriate for this kind of research simply because nearly all manufactured products are solid, although some of the interesting optical effects can also be produced in gases and liquids.
There is strong interest in such research from both technological and commercial standpoints. Transistors in an integrated circuit, for example, are on the scale of 'small' as defined above. Hall and Howard Stuart, one of his graduate students, discovered that a layer of nano-particles (much smaller still, only one tenth the wavelength of light in size) on silicon photodetectors can greatly increase the sensitivity of the photodetector. Although this has been demonstrated experimentally, the underlying physics is not clear.
Scott Walck, an RTC post-doc in Hall's group, is working on theoretical modeling of the physical process. While the experimental finding has already been published in Physical Review Letters, and followup lab studies are beginning, it's too early to say whether this discovery may lead to new innovations in optics-based telecommunications. Any theoretical clarification coming from Walck's work is likely to uncover ways to extract additional benefits from the discovery. While the effects being explored appear to be far from commercial application, Dr. Hall offers the reminder that "...one need only look at ... microelectronics or optical communications industries to see what can emerge from research on the properties of micro and nanoscale structures."
Dr. Victor Kozlov arrived in January from the University of St. Petersburg, Russia, where he is a senior researcher in the Institute for Physical Research, Department of Quantum Electronics in the Laboratory of Laser Physics. Dr. Kozlov earned his Ph.D. in laser physics at St. Petersburg State University with Professor Evald Fradkin, the chief of the laboratory. He recently spent 2 years as a postdoctoral fellow at Texas A&M University, working in the well-known quantum optics group of Marlan Scully and Olga Kocharovskaya. His work at RTC will include the theory of pulse propagation through three-level resonant media, the amplification and absorption of few-cycle pulses, and propagation of chirped simultons.
In February, Dr. Hong Guo arrived from Guangzhou, China, where he is Professor and Director of the Laboratory of Light Transmission Optics in South China Normal University. His research has included work on laser beam propogation, laser cooling and trapping and laser-matter interaction physics. While he is in Rochester, he will join an advanced numerical modelling project focused on the behavior of ultrashort light pulses in absorbing materials. Dr. Guo earned his Ph.D. at the National Laboratory on High Power Lasers and Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences.
Dr. Ali Kamli will arrive in August for a 12 month visit. He is an assistant professor at King Saud University in Abha, Saudi Arabia. Professor Kamli recently joined the AMO community when he became interested in photonics and quantum optical effects. Earlier he had written on the gauge dependence of the Dyson-Schwinger Equation for dynamically generated fermion masses in Technicolor theories for his Ph.D. at Southampton University in England. His recent work includes papers on the dipole emission rate in doped photonic crystals as it is affected by impurities, and on dipole relaxation in asymmetric waveguides.
The unifying theme of the SILAP Workshop will be Relativistic Effects in Strong Fields. The primary purpose of the workshop is to bring together researchers from diverse areas, where the term "strong field" has different meanings. It is expected that the meeting will create a stimulus for new approaches. These different areas include atomic physics, heavy-ion collisions, plasma physics, and ultra-short laser physics. All of these fields are experiencing vigorous progress in the exploration of relativistic effects due to strong fields.
Representatives from US and European institutions will be in attendance and speaking. The list includes Université Pierre et Marie Curie, Illinois State University, Lawrence Berkeley Laboratory, University of Freiburg, Lawrence Livermore National Laboratory, University of Michigan, Max Planck Institute for Quantum Optics, University of Rochester, and University of Bielefeld.
The Workshop will be located on the campus of American University on May 28-30, 1999, as a satellite following the major optics and lasers conference CLEO/QELS being held in Baltimore, May 24-28, 1999. Those interested may inquire about registration via e-mail with Howard Reiss at American University (reiss@american.edu) or Rainer Grobe at Illinois State University (grobe@phy.ilstu.edu), who are acting as co-organizers of the Workshop. Space is limited.
Branning and Walmsley have posed the question of whether the nonlinear optical process of parametric down-conversion, where the frequency of light is shifted down by a nonlinear crystal, can be used to 'quantum teleport' the frequency of photons generated by ultrashort pulses of light. This is an illustration of the power that experiments in nonlinear optics can have in helping to understand implications for the quantum physics of light. This fact has obviously motivated much of Professor Mandel's recent work, as well as Branning's research with Walmsley's group.
Quantum teleportation is a speculative technology that makes use of the nonlocal aspect of quantum mechanics, Einstein's 'spooky action-at-a-distance'. Entangled particles, usually photons, carry information about each other that can be instantaneously transmitted over macroscopic distances. This enables emerging applications like quantum cryptography.
Dr. Branning's thesis research, which involved using parametric down-conversion to test quantum interference and entanglement among photons, was carried out in the group of Prof. Leonard Mandel, a pioneer in the field and a senior member of RTC. At NIST Branning studies, among other things, the use of photons generated by nonlinear optics for calibrating photodetectors.
In a recent Physical Review Letter, Dr. Shah and one of his colleagues, Dr. Dan Birkedal, reported their observations of anomalies in the resonance Rayleigh scattering (RRS) of ultrafast laser pulses by excitons (bound electron-hole pairs) in semiconductor quantum wells. They found that the RRS signal, which arises because the resonance frequency of the exciton depends on its spatial location in the well, displays phase correlations that are unexplained by existing theories.
During a visit to RTC by Birkedal and Shah last October, Birkedal reported their findings in an RTC seminar. This is when Shchegrov began to get involved. His thesis work at UC-Irvine on the scattering of light from optically rough surfaces bore a certain resemblance to the work at Bell Labs. While not an expert on the subject of excitons and quantum wells, his experience with scattering theory and its numerical methods may be key to addressing the theoretical questions uncovered by the Lucent group.
The impetus for work on this research theme at Bell Labs comes partly from fundamental curiosity about quantum well behavior and partly from the need to understand better the nature of light scattering in carefully structured semiconductors. This has implications for the performance and stability of opto-electronic devices such as semiconductor lasers, one of Lucent's specialties.
The lure of a new field with a theoretical puzzle, and the chance to work with Lucent, a world-renowned systems and technology company, drew Shchegrov to the project. Before coming to RTC, Shchegrov carried out his doctoral studies at UC-Irvine under the direction of the internationally known condensed matter theorist, Professor Alexei Maradudin. Working in RTC, Dr. Shchegrov has been contributing to the research of Professor Emil Wolf's group and in frequent discussions with Professors Knox and Eberly as well.
Sergei Tretiak
"Collective Electronic Excitations in Spectroscopy of Conjugated and Aggregated Molecules"
Ph.D. Thesis, Department of Chemistry (University of Rochester, 1998).
Supervised by Shaul Mukamel.
P. Scott Carney and Emil Wolf
"An Energy Theorem for Scattering of Partially Coherent Beams"
Optics Comm. 155, 1 (1998).
G. Gbur and P.S. Carney
"Convergence Criteria and Optimization Techniques for Beam Moments"
Pure Appl. Opt. 7, 1221 (1998).
T.D. Visser, P.S. Carney and E. Wolf
"Remarks on Boundary Conditions for Scalar Scattering"
Phys. Letts. A 249, 243 (1998).
Paolo Bellomo, C.R. Stroud, Jr., David Farrelly, and T. Uzer
"Quantum-Classical Correspondence in the Hydrogen Atom in Weak External Fields"
Phys. Rev. A 58, 3896 (1998).
Paolo Bellomo and C.R. Stroud, Jr.
Comment on "Coherent States for the Hydrogen Atom"
Phys. Rev. A 59, 900 (1999).
Y. Zhao, V. Chernyak and S. Mukamel
"Spin versus Boson Baths in Nonlinear Spectroscopy"
J. Phys. Chem. A 102, 6614 (1998).
W. M. Zhang, T. Meier, V. Chernyak and S. Mukamel
"Simulation of Three-Pulse-Echo and Fluorescence Depolarization in Photosynthetic Aggregates"
Phil. Trans. Royal Soc. A 356, 405 (1998).
W. M. Zhang, T. Meier, V. Chernyak, and S. Mukamel
"Exciton-Migration and Three-Pulse Femtosecond Optical Spectroscopy of Photosynthetic Antenna Complexes"
J. Chem. Phys. 108, 7763 (1998).
V. Chernyak, W. M. Zhang and S. Mukamel
"Multidimensional Femtosecond Spectroscopies of Molecular Aggregates and Semiconductor Nanostructures; The Nonlinear Exciton Equations"
J. Chem. Phys. 109, 9587 (1998).
W.M. Zhang, V. Chernyak, and S. Mukamel
"Two-Dimensional Femtosecond Spectroscopies of Coupled Chromophores"
In Ultrafast Phenomena XI, edited by T. Elsaesser, J. G. Fujimoto, D. A. Wiersma, and W. Zinth, Springer Verlag, Berlin (1998), 663.
S. Mukamel,W. M. Zhang, and V. Chernyak
"Structure Determination of Antenna Complexes Using Two-Dimensional Femtosecond Electronic Spectorscopies"
Proceedings of XIth International Congress on Photosynthesis, G. Garab and J. Pusztai, Eds., Kluwer, Dordrech, Netherlands (1998).
G. Bazan, W. Oldham, R. Lachicotte, S. Tretiak, V. Chernyak, and S. Mukamel
"Stilbenoid Dimers: Dissection of a Paracyclophane Chromophore"
J. Am. Chem. Soc. 120, 9188 (1998).
S. Tretiak, V. Chernyak, and S. Mukamel
"Localized Electronic Excitations in Phenylacetylene Dendrimers"
J. Phys. Chem. B 102, 3310 (1998).
S. Tretiak, V. Chernyak and S. Mukamel
"Excited Electronic States of Carotenoids; Time-Dependent Density-Matrix-Response Algorithm"
Intl. J. Quant. Chem. 70, 711 (1998).
S. Tretiak, V. Chernyak, and S. Mukamel
"Real-Space Analysis of Electronic Excitations in Free-Base (H2P) and Magnesium (MgP) Porphins"
Chem. Phys. Lett. 297, 357 (1998).
"Impact of PMD-induced Pulse Distortion on High Bitrate Transmission Systems"
Ralph Leppla,
Deutsche Telekom, Darmstadt.
"Optical Fiber Multi-wavelentgh System Modeling"
Dipak Chowdhury,
Corning, Inc., Corning NY.
"Ultrafast Interferometric Investigations of Resonant Secondary Emission from Semiconductor Quantum Wells"
Dan Birkedal and Jagdeep Shah,
Bell Laboratories,
Lucent Technologies, Holmdel, NJ.
"Coherent Radiation in Optically Dense Media"
Susanne Yelin,
Air Force Research Laboratory,
Hanscom AFB MA.
"The Physics of Precision Optics for Application in the Microelectronics Industry: The World's First Accurate Interferometer"
R.R. Freeman,
UC-Davis and Lawrence Livermore National Laboratory, Livermore CA.
RTC Lecture Series on Quantum Computers:
1. "Qubits without Tears: A Friendly Introduction to Two-level Systems, Entanglement and Quantum Computers"
2. "Error Correction in Quantum Computers"
Daniel James,
Theoretical Division,
Los Alamos National Laboratory, Los Alamos NM.
RTC Report:
Edited by Joel Byam
Contributors: Susan Murphy and Ashok Muthukrishnan
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