RTC REPORT:   Winter 1996-97

Charles Clark on Industrial Internships at RTC

We interviewed him about RTC and the value of industrial internships, which are beginning to be arranged for RTC postdocs. One of Dr. Clark's former students, Wei-Chih Liu, will hold the first internship and will work for an extended period as a visiting team member in the Optical Data Storage Group of the Kodak Research Laboratories.

RTC:  How can a young theoretical physicist like Dr. Liu benefit from a chance to sample the "flavor" of industrial research ?

CLARK:  Industry provides very attractive career paths for physicists who want to solve challenging research problems, which often require knowledge and techniques from other disciplines. For theorists in particular, I think there are likely to be a growing number of opportunities due to increased appreciation by industry of the value of modelling and simulation as an adjunct to laboratory simulation.

RTC:  Which industries in particular ?

CLARK:  This trend has been apparent in the pharmaceutical and chemical industries for some time. I can imagine that the increasing incorporation of nonlinear optical components and the integration of micromachined optics with microelectronic circuitry will pose formidable new industrial design problems. Other areas of emerging optical application, like biomedicine and data storage, clearly many issues that should be attractive to a creative theoretician.

Let me note that the National Institute of Standards and Technology where Dr. Liu's Ph.D. work was largely done, is in many respects like that of an industrial research laboratory. We tend to work as groups of multiple senior investigators on problems that have a pretty direct bearing on NIST's mission of maintaining the national standards infrastructure and advancing measurement technology.

RTC:  Given that Dr. Liu hasn't worked in the field before, why do you think the Optical Data Storage Group at Kodak invited him to work with them ?

CLARK:  During his Ph.D. studies, Dr. Liu developed a number of innovative approaches to solving the Shrodinger wave equation on parallel computers. However, Liu's basic technical approach is also readily applicable to the electromagnetic wave equation, which governs the propagation of light through the wavelength-size structures that are of interest to Kodak's Optical Data Storage Group. So I suppose that group wants someone who knows how to solve wave propgation problems in very unusual situations.

RTC:  Any comments on RTC ?

CLARK:  The RTC is the first NSF-supported center for theory in the field of optical science and engineering. One of its missions - to integrate advanced optical theory into the industrial research environment - certainly differentiates it from other NSF theory institutes. Extended industrial internships, such as the one Dr. Liu is beginning with Kodak, seem like a promising strategy to help attain this ambition objective. We shall see.

RTC Cooperates with NASA

Principal non-NASA speakers at the Workshop included W. Ketterle (MIT), S. Rolston (NIST), D. Heinzen (Texas), J. Javanainen (Connecticut), D. Salomon (French Space Agency), J. Bergquist (NIST), and K. Gibble (Yale).

According to NASA's Enterprise Scientist for Fundamental PHysics, Mark C. Lee, who termed the gathering "a great success," almost all of the workshop's recommendations have already been incorporated into the agency's current Microgravity Fundamental Physics Research Announcement. The announcement solicits ideas for ground-based and space experiments on the International Space Station (ISS) for the year 2003 and beyond.

In comments after the workshop, Lee said that the microgravity workshop was a "prime example of how the academic community and NASA can work together to benefit the nation." Lee remarked that RTC "was more than helpful in organizing this critically needed workshop... the kind really needed by NASA and other federal government agencies - especially in the current era of tight federal research and development funding."

Working groups at the Laser Cooling and Atomic Physics (LCAP) Microgravity Challenge Workshop addressed issues ranging from gravitometers and atom lasers, through atomic clocks and the technology of space traps, to space experiments dealin gwith Bose-Einstein condensation and quantum computation. All of these are of interest to RTC, and various Theory Center members participated in the discussions. In the prepared talks, both theorists and experimenters presented specific "challenges" facing the growing microgravity community. In particular, the challenge spotlights fell on scientific issues relevant to low gravity environments that were being overlooked or neglected or that deserved broader attack or expanded funding in light of recent developments.

Mark Lee indicated that he looks forward to similar workshops in the future, at least one annually, to guide LCAO research work.

Spanish Professor Arrives at RTC

Born in Madrid, Santos completed his Ph.D. at the University of Vigo in 1995. Part of his graduate work was undertaken at the University of Essex in the United Kingdom. There he worked with Professor Rodney Loudon on the theory of continuous mode quantization, extending previous schemes to dielectric materials in which the dielectric function varies with position as well as with frequency. He holds the title of Doctor in Telecommunications Engineering and has taught courses in Communication Electronics, Introduction to Opto-electronics, Optical Communications, Quantum Mechanics for Engineers, and Introduction to Quantum Electrodynamics. Santos' fields of expertise are wide ranging. They include quantum optics, nonlinear optical devices, opticalcommunications, communication electronics, and signal processing.

First RTC Industrial Internship

Under the arrangement with Kodak, Dr. Liu will spend four days a week at the Kodak Research Laboratories in Rochester. He will join with Drs. J.E. Durnin and M. Kowarz in their research into the diffractive interaction of light with wavelength-scale structures.

Currently the group is working on ways to miniaturize compact disk groove designs to allow CDs to hold more information. However, it also makes the CDs more difficult to read since light can't easily get into the tiny grooves. Liu's outstanding mathematical skills and experience with grid-based numerical solutions of wave equations are expected to aid the Kodak group as they try to overcome this non-trivial problem, according to RTC Director J.H. Eberly, who has worked with kowarz and Durnin to establish this collaboration between industrial and academic researchers.

Dr. Liu received his B.S. and M.S. in physics from the National Taiwan University in Taipei. His Ph.D. in chemical physics was awarded at the University of Maryland, College in Park in December 1996. Advised by Dr. Charles W. Clark, his thesis title was "High-Order Radiative Processes in Atoms in Intense Laser Fields."

As a graduate student, Liu worked as a guest researcher in the Electron and Optical Physics Division, Physics Laboratory at the National Institute of Standards and Technology in Gaithersburg, MD. His projects there included high-order frequency-dependent nonlinear optical processes of helium and theory of high harmonic generation with elliptically polarized light.

While at RTC, in addition to the Kodak project, Liu is interested in working on supershort matter-field interactions and on electromagnetica near-field effects. The latter is for him "a totally new area" that he thinks will be exciting to explore.

Dr. Yang Zhao Joins RTC As Newest Post-doc

His first project as an RTC post-doc is a collaboration with Professor Shaul Mukamel's group on polaron mechanisms for superradiance in molecular aggregates. Remarkably rapidly, Dr. Zhao's presence has contributed to a finished report with T. Meier, V. Chernyak and Professor Mukamel, titled "Superradiance in molecular aggregates: real-space density-matrix analysis of excition coherence sizes." It has been submitted to the Jounral of Chemical Physics.

Since arriving he has also worked on calculations of linear absorption and pump-probe signals for a dimer by constructing multi-gaussian wavepackets from optimized polaron wavefunctions, as well as on the development of time-dependent wavepackets for modeling various optical responses of molecular aggregates.

A 1988 graduate of Zhejiang University in China, with a B.A. in physics, Zhao earned his M.S. and Ph.D. in physics at the University of California at San Diego. His Ph.D. thesis, directed by Professor Katja Lindenberg, Head of UCSD's Chemistry Department, was entitled "Variational Ground States of THe Holstein Hamiltonian." It was motivated by what Zhao perceived as a lack of theory to explain optical excimer spectra and transport properties in aromatic organic crystals. His thesis project focused on examining the effect of off-diagonal excition-phonon coupling, which has been customarily omitted due to difficulties involved in obtaining reliable solutions.

Flash!   RTC Postdoc Puts New "Spin" on Structure of the Universe

While studying data by astronomers on the polarization of radio waves emitted as synchrotron radiation from distant galaxies, the two found that the plane of polarization rotates as the radiation propagates through space. This rotation, the well-known Faraday effect, is common in optical transmission and is detected in space via the influence of intergalactic magnetic fields on propagating radio waves.

It was after subtracting the Faraday effect from the astronomical data that Nodland made his discovery: an extra rotation that was dependent on the direction the radiation came from in the universe. This directional dependence of the non-Faraday rotation, according to nodland's thesis, indicates that space is, unexpectedly, not isotropic with respect to electromagnetic interactions. A modification of the standard picture of the fundamental structure of space is not to be taken lightly, of course, and Nodland continued testing his theory at RTC with Monte Carlo statistical calculations by computer.

Kimble Comments on RTC Visitor

His visit left Kimble with a positive impression of RTC's program. In kimble's words, "RTC serves as an important bridge between theoretical and experimental communities and will clearly impact the future direction of my research." In an email interview, with specific reference to Dr. Law's contributions, Kimble generously remarked that "In addition to working out a concrete scheme for the generation of an arbitrary stream of single photon pulses, Law sorted through other ideas related to the same problem and to another: a one-atom laser." Thanks to Dr. Law's visit, Kimble's group now "has a better idea of which experiments are workable ('good') and which are not so sensible ('bad'), given Caltech's current experimental capabilities."

As an observer with a fresh understanding of the lab's leading-edge capabilities, Dr. Law was able to suggest a new experiment that could allow production of a very efficient single-photon stream in which binary information could be encoded. He expects that this "single-photonic" device, which he compares to a pistol in which each single-photon bullet can be discharged on command, may have applications in ares such as quantum cryptography and quantum computation.

RTC Publications

"Femtosecond Spectroscopic Signatures of Electronic Correlations in Conjugated Polyenes and Semiconductor Nanostructures", T. Meier and S. Mukamel, Phys. Rev. Lett. 77, 3471 (1996).

"Principles and development of diffraction tomography", E.Wolf, Current Trends in Optics, Vol. 3, edited by A. Consortini, Academic Press (1996).

"Electronic excitation transfer in the photosynthetic unit: Reflections on work of William Arnold", R.S. Knox, Photosynthesis Research 48, 35-39 (1996).

"Universal relationship between optical emission and absorption of complex systems: An alternative approach", D.A. Sawicki and R.S. Knox, Phys. Rev. A54, 4837-4841 (1996).

"Correlation-induced spectral changes and energy conservation", G.S. Agarwal and E. Wolf, Phys. Rev. A 54, 4424-4427 (1996).

"Theory of diffraction tomography for quasi-homogeneous random objects", D.G. Fischer and E. Wolf, Optics Commun. 133, 17-21 (1997).

"Rate-equation approximations in high-gain lasers", Lee W. Casperson, Phys. Rev. A 55, 1-13 (1997).

RTC Calendar

Laser Cooling and Atomic Physics Microgravity Challenge Workshop.
Organized by N.P. Bigelow and J.H. Eberly.
Co-sponsored by the Microgravity Program of NASA.

NOVEMBER 1996

RTC Special Informal Seminar & Colloquium.
Lecturer:  Professor P.L. Kelley, Senior Visiting Fellow.
Informal Seminar:  "The Use of Renormalization Techniques in Nonlinear Optics."
Colloquium:  "Non-perturbative nonlinear optics."
Professor Kelley is director of the Electro-Optics Technology Center, Tufts University.

RTC Lecture Series on Interaction of Crossed Beams in Inertial-Confinement-Fusion Plasmas.
Lecturer:  Professor Vladimir Tikhonchuk, Senior Visiting Fellow.
Lecture 1:  "Stimulated Brillouin scattering of a spatially smoothed laser beam."
Lecture 2:  "Nonlocal theory of electron transport in unmagnetized plasmas."
Professor Tikhonchuk is with the P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow.