University of Maryland Institute for Research in Electronics and Applied Physics

Institute for Research in Electronics and Applied Physics

Rajarshi Roy 
Professor, Department of Physics and Institute for Physical Science and Technology

Ph.D., University of Rochester, 1981

Phone: (301) 405-1636
Room:  A. V. Williams  3347 


Current Research

The study of nonlinear dynamics and noise in optical devices and systems is relevant to very practical technological applications such as compact disk players, fiber optic communications, and the development of optical switching devices and laser arrays. At the same time, nonlinear phenomena that are observed in devices and systems of current interest may often be very interesting from a fundamental perspective. 

An effort to understand nonlinear dynamical phenomena in laser systems, for example, may lead us to confront a very basic question - namely, under what conditions can we discern the influence of quantum fluctuations on the chaotic dynamics of a macroscopic system? Novel experimental schemes and techniques for analysis of data from nonlinear systems must be combined to approach this problem, and it is necessary to develop fully quantum mechanical models of nonlinear systems to predict the outcome of such experiments. If quantum noise does significantly influence the macroscopic dynamics of a nonlinear system under certain conditions of operation, it will definitely impact our ability to actively control the chaotic dynamics of these devices by deterministic techniques. The control and synchronization of chaotic devices is important technologically, since it may be possible to use chaotic lasers for encoding and decoding information-carrying signals.

Recent Publications
  1. "Spatiotemporal Communication with Synchronized Optical Chaos," J. Garcia-Ojalvo and R. Roy, Phys. Rev. Lett. (June 2001)PDF

  2. "Detecting Phase Synchronization in a Chaotic Laser Array," D. DeShazer, R. Breban, E. Ott, and R. Roy, Phys. Rev. Lett. 87, 044101 (2001).PDF

  3. "Dynamics of Activated Escape and Its Observation in a Semiconductor Laser," J. Hales, A. Zhukov, R. Roy, and M. I. Dykman, Phys. Rev. Lett. 85, 78-81 (2000).PDF

  4. "High-Speed Fiber-Optic Polarization Analyzer: Measurements of the Polarization Dynamics of an Erbium Doped Fiber Ring Laser," G. D. VanWiggeren and Rajarshi Roy, Opt. Comm. 164, 107-120 (1999).PDF

  5. "Transmission of Linearly Polarized Light through a Single Mode Fiber with Random Fluctuations of Birefringence," G. D. VanWiggeren and Rajarshi Roy, Appl. Opt. 38, 3888 (1999).PDF

  6. "Synchronization of Chaos in an Array of Three Lasers," J. R. Terry, K. Scott Thornburg, D. DeShazer, G. D. VanWiggeren, S. Zhu, P. Ashwin, and Rajarshi Roy, Phys. Rev. E 59, 4036 (1999).PDF

  7. "Chaotic Communication Using Time-Delayed Optical Systems," G. D. VanWiggeren and Rajarshi Roy, Int. J. Bif. Chaos 9, 2129 (1999).PDF

  8. "Blowout Bifurcation in a System of Coupled Chaotic Lasers," P. Ashwin, J. Terry, K. S. Thornburg, Jr., and Rajarshi Roy, Phys. Rev. E 58, 7186 (1998).PDF

  9. "Polarization Based Data Storage in Fiber Ring Lasers," J. García-Ojalvo and Rajarshi Roy, Quant. Semiclass. Opt. 10, 723 (1998).Abstract

  10. "Optical Communication with Chaotic Waveforms," G. D. VanWiggeren and Rajarshi Roy, Phys. Rev. Lett. 81, 3547 (1998).PDF

  11. "Dynamical Evolution of Multiple Four Wave Mixing Processes in an Optical Fiber," Darlene Hart, A. Judy, Rajarshi Roy, and J. W. Beletic, Phys. Rev. E 57, 4757-4774 (1998).PDF

  12. "Communication with Chaotic Lasers," G. D. VanWiggeren and Rajarshi Roy, Science 279, 1198 (1998).PDF

  13. "Intracavity Chaotic Dynamics in Ring Lasers with an Injected Signal," J. García-Ojalvo and R. Roy, Phys. Lett. A 229, 362 (1997).Abstract

  14. "Fast Intra-Cavity Polarization Dynamics of an Erbium Doped Fiber Ring Laser," Q. L. Williams, J. García-Ojalvo, and Rajarshi Roy, Phys. Rev. A 55, 2376 (1997).PDF

  15. "Encoding and Decoding Messages with Chaotic Lasers," P. M. Alsing, A. Gavrielides, V. Kovanis, Rajarshi Roy, and K. S. Thornburg, Jr., Phys. Rev. E 56, 6302-6310 (1997).PDF

  16. "Influence of Noise on Chaotic Laser Dynamics," C. Liu, Rajarshi Roy, H.D.I. Abarbanel, Z. Gills, and K. Nunes, Phys. Rev. E 55, 6483-6500 (1997).PDF

  17. "Chaos and Coherence in Coupled Lasers," K. Scott Thornburg, M. Moeller, Rajarshi Roy, R. Li, T. Carr, and T. Erneux, Phys. Rev. E 55, 3865 (1997).PDF