Acccording to Marek Kowarz, Kodak Senior Research Scientist and OST group leader, this type of modeling is usually done with an approximate scalar theory that does not fully take into account the true electromagnetic boundary conditions that exist at interfaces between different materials.
Kowarz credits Liu with the development of a novel numerical algorithm that makes it possible to calculate efficiently the optical interaction between laser and disc. To date, the algorithm has been implemented in two dimensions, and its accuracy has been verified. Once Liu extends the algorithm to three dimensions Kodak scientists will use it to examine real optical disk interface problems.
One of Liu's results has already been featured on the first-issue cover of the journal Optics Express (see figure).
Kowarz expects that the RTC internship program, which has had a satisfactory kick-off thanks to Liu's efforts, will foster other, long-term collaborations between Kodak Optical Storage R&D scientists and other members of the Theory Center.
RTC: How did you react to Professor Eberly's invitation to speak at a conference outside of your
field ?
WPR: The Rochester Theory Center has certainly shown itself well in hosting a most interesting workshop. At first I thought it was going to be a general meeting on 'optical solitons' rather than 'solitons and fiber optics communications ! So I was quite amused when I saw the program. I realized I would be the odd man out because all the other talks were addressing a quite important but narrow practical problem: how to get 100 Gb/sec through a fiber.
My conclusion was that I had been invited for cultural broadening. After I called Joe and confirmed this I was happy to come. And, of course, I still hoped to learn new things about solitons, as this is a new area for me.
RTC: Do you think you were well-received by the "fiber guys" ?
WPR: I think that once the group realized that I was not one of the fiber optics crew they relaxed and were interested in seeing that some of the same ideas they have used for years have a new and exciting life in a very new area of physics: the dynamics of the essentially zero temperature gaseous Bose-Einstein Condensate. In particular, Ildar Gabitov, who is an expert on the mathematical aspects of solitons (having been trained by Zakharov - the father of the soliton dynamics for the Nonlinear Schrodinger Equation) was very excited to see that quite a new area, where solitons play an important role, is just opening up. So from the point of view of cultural broadening I think my talk was a success.
RTC: What did you learn from the Workshop that you will find useful in future work?
WPR: The workshop was far more valuable than I had expected. I have now read a good sampling of the modern soliton-optics literature, including Govind Agarwal's text "Nonlinear Fiber Optics." I have greatly benefitted from the simple qualitative physical pictures used by those in fiber optics to understand what is happening Further, even though in my talk all of the solitons were "dark" while the fiber solitons of the workshop were "bright", it turns out that my newly gained feeling for such "bright" solitons may well have some surprising ramifications for thinking about the gaseous lithium BEC, where the atomic interactions are attractive. Many people have tried to visualize the collapse of such a condensate. Now, however, it is clear to me that it won't collapse. Rather it will spin off solitons either as free BEC packets or as bound multi-soliton states. This was well known to the fiber optics community but will now be quickly transmitted into the BEC thinking. Cultural broadening goes both ways.
As a Ph.D. student under Professor Turgay Uzer, he wrote his thesis on "Classically Non-integrable Quantum Systems." His Master's thesis was entitled "Polygonal Billiards: A study of the Connection Between Classical Periodic Orbits and Quantum Eigenvalues."
At RTC he hopes to work with PRofessor Eberly's and Stroud's groups studying "Trojan" atomic states, a subject he's acquainted with because his thesis advisor Uzer has done research in that field.
Having worked on ZEKE-PES states and Rydberg states with very high principal quantum numbers, Bellomo believes he is familiar with many of the techniques typically needed in the the study of Rydberg electrons.
He's also interested in getting into a new area for him - solitons and their applications. The opportunity of working with RTC theorists in this area and his own strong background in nonlinear dynamics and quantum chaos is a combination that he hopes will make his transition into optics a relatively smooth one. In particular, he looks forward to doing work in fiber optics and communications.
While in Rochester, Kneer interacted with many RTC members and spoke at two informal group seminars, attended by visiting scientists. His talks described a new method of arbitrary photon state preparation. At the annual meeting of the OSA in Rochester he gave a talk on the subject of "Quantum Imaging: Converting Digitalized Images in to a Quantum Mechanical Wave Function."
It was Kneer's second visit to Rochester and RTC. During the first visit he worked with Eberly and Law in a collaboration that continued during the Fall visit. A by-product of his visit was "learning how the American Ph.D. system works and the differences between it and the German one."
Kneer's brief pre-doctoral fellowship was remarkably productive. Three articles were generated. One concerned the two-dimensional-state preparation method entitled "Preparation of an arbitary density matrix of a harmonic oscillator." It will appear in the special issue of the Journal of Modern Optics devoted to Quantum State Preparation and Measurement.
The second article includes both analytical and numerical results for the ionization of a Trojan wave packet for a delta pulse, and numerical results for the ionization cross-section of a Trojan wave packet for a delta pulse in case of a plane wave continuum. A third, on entangled quantum states in Paul trap," is still in prepartion.
Kneer expects to finish his Ph.D. by the end of 1998. Although currently working in the area of atomic lasers, he hasn't yet selected a specific thesis topic.
RTC: Let's start with the bottom line. Was the workshop a success ?
GABITOV: The workshop was unanimously considered a great success by the participants. The informal style of working, the balanced composition of participants, the questions discussed, and the well-focused theme of the work allowed us to draw conclusions and define the main means for developing high-speed communication technology.
DULING: Yes. Personally it was the right information at the right time. Often workshops of this kind consist of everyone giving slightly related talks, with little interaction. In contrast, I found this one to be both stimulating and enjoyable. I was fascinated by the range of experts present.- which generated lively discussion and wonderful cross fertilization.
GABITOV: Many of the participants expressed their hope that this workshop will become a tradition. One has to underscore the excellent organization by the colleagues of the Rochester Theory Center.
RTC: Was the workshop aimed at industrial or academic scientists ?
GABITOV: An important task of our workshop was to get those two groups together--representatives of industrial and academic science in the area of high-speed telecommunications - and to select the best of both approaches, to give new impetus in this new and fast-developing area. (Editor's Note: Workshop attendees represented the following companies, universities and agencies: Alcatel SELAG, BT Labs, Bell Labs, Chalmers University of Technology, Corning, Inc., Deutsche Telekom, the University of Maryland, Naval Research Lab, Rensselaer Polytechnic Institute, the University of Rochester and the University of Washington).
RTC: Did either of you learn anything at the workshop that will be useful in your own work ?
DULING: As we are just in the process of putting together some propagation experiments, I was fascinated to see the progress in dispersion managed systems.. The talks presented were the seeds for new ideas in how those experiments should be designed.
GABITOV: I learned from Professor Reinhardt's talk on new research in the field of low temperature physics, that ( in an amazing way) the models describing the dynamics of a Bose gas are identical to the models of pulse propagation in optical transmission lines with dispersion management. This was a surprising example of the universality of science.
DULING: In the area of high-speed optical communications (40 Gb/s and above) there is a great need for perspective. There are a large number of options, each with its own set of difficulties. Knowing which of these options are feasible from a scientific and economic standpoint is very important now.
GABITOV: One feature that distinguishes computer data transfers from telephone calls is the huge possible volume of transferrable information which can now be transferred only along optical fibers.
DULING: Regarding soliton communications, one area I hoped would be covered during the workshop was dispersion managed systems. How far can these systems take us, how should they be designed, how should they be analyzed (or are they still soliton systems at all)? Is there really a necessity for optical processing (even rudimentary all-optical routing) in future networks? What will be the format of those future systems? As it turned out, all these questions were addressed at one time or another during the workshop - which laid a good foundation on which to build answers to them.
RTC has its first "graduate." The honor goes to Maciej Kalinski, who received his Ph.D. in July 1997. He spent the last two summers working on an RTC project with Professor Eberly on electron localization in strong light fields. This September he will go to Louisiana State University as a postdoc. There he plans to study the ionization dynamics of small clusters of atoms in short, intense laser pulses, and inner-shell stripping with application to novel ultraviolet and x-ray sources.
RTC's second Summer Symposium provided a forum for nine graduate students to talk about the optical science or engineering project they had worked on over the summer. Each student received RTC funding, while working under the guidance of their academic advisors, who are all affiliated with RTC.
This year's Symposium was a two-day affair, held on August 21, 22. In addition to the 20 minute talks by the summer students, RTC Postdocs C.K. Law, Borge Nodland, Wei-Chih Liu and Yang Zhao were invited to give short talks about their ongoing projects. Members of the RTC Advisory Board were also present, some acting as session chairs.
The graduate student speakers with their advisors and their talk titles were:
Han Pu (Bigelow): "Properties of Double Bose Condensate."
Edward Startsev (McKinstrie): "Relativistic ponderomotive force of light, and Langmuir waves."
Sergei Tretiak (Mukamel): "Collective Optical Excitations of Conjugated Molecules."
Edward Turano (McKinstrie): "Stimulated Raman scattering of a short laser pulse in a plasma channel."
Jim West (Stroud): "Core scattering dynamics of Rydberg wave packets."
Weimin Zhang (Mukamel): "Femtosecond Spectroscopy of Excitons in Photosynthetic Complexes."
Pamela Greene (Hall): "The lasing threshold of a circular-grating semiconductor laser."
Howard Stuart (Hall): Coupling between nanoparticle resonances and the modes propagating in a nearby optical waveguide."
RTC: First, your overall reaction to the conference? How would you rate it on a scale of 1-10 ?
FORBES: It was one of my all time favorite meetings. A 10 in my book.
RTC: Why have a workshop on Asymptotic and Approximate Methods in Optical Modeling ?
FORBES: When Joe mentioned the idea of such a Workshop, I thought itwould be great. Optical modelling is a growing discipline that thrives on computer horsepower and the introduction of new optical technologies that need to be modelled effectively to facilitate design. There are a range of developments in this area that could be brought together by collecting the relevant people so that things can be coupled directly where appropriate.
RTC: Such as ?
FORBES: For example, new work in rigorous diffraction is helpful to those working in asymptotic and approximate methods to give a better understanding of accuracy and validity. Some of the new work in asymptotics relates to wave phenomena across the board and the Workshop could bring together people from different wave domains. Some of the approximate methods have been developed for forward problems, but relate also to "inverse" problems and this community could also be involved.
RTC: Did the workshop accomplish these goals ?
FORBES: The meeting did all these things and more. For example, it brought together Jakob Stamnes and Marek Kowarz who had both worked on closely related developments but had never had the opportunity to interact directly.
RTC: Have you had any feedback from any workshop attendees ?
FORBES: I heard only very positive feedback .Not only about the level of talks, but about the usefulness of the interactions, and the general hospitality extended by the RTC. There was certainly interest in having such a meeting again and this included some of those who were unable to attend this one. Perhaps every other year would be appropriate.
RTC: What did you get from the workshop that could be of use in your upcoming or ongoing projects ?
FORBES: For me personally, I learned of subtleties in asymptotics thatcaused changes in a paper that I had recently submitted (a copy of which is in the Workshop Booklet). I learned of tricks with FFTs that Siegman, Lawrence, and Mansuripur have developed that I will now use in my wave modelling. (All three have sent me relevant materials.) I will also be working with Jakob Stamnes in the future regarding further development of the ideas on rigorous diffraction that he presented. The contacts with others whom I hadn't met was also a great plus.
RTC: What would you do differently if you were to arrange a similar workshop in the future ?
FORBES: Not a lot. I would probably try and be a little better organised earlier on, but this is probably a pipedream!
RTC: Any thoughts on RTC ?
FORBES: What a fantastic idea. I hope it has a long and prosperous life.
Workshop on Advanced Concepts in High-Speed Optical COmmunications, organized by G.P. Agrawal and Ildar Gabitov.
JUNE 1997
Workshop on Asymptotic and Approximate Methods in Optical Modeling, organized by G.W. Forbes and J.H. Eberly.
AUGUST 1997
RTC Summer Symposium.
RTC Report:
Edited by C.S. Lavine
lavine@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