The Cooperative Transverse Modulational Instability of Counterpropagating Waves
Total Page:16
File Type:pdf, Size:1020Kb
THE COOPERATIVE TRANSVERSE MODULATIONAL INSTABILITY OF COUNTERPROPAGATING WAVES Gregory G. Luther Submitted in Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY Supervised by Professor Colin J. hlcI<instrie Department of Mechanical Engineering College of Engineering and Applied Science University of Rochester Rochester, New York Curriculum Vitae The ailihcr wds Lori! or, December 1, 1962 in Rochester, New k'ork. Eie earned the Bachelor of Science degree in Mechanical Engineering, with distinction, at the University of Rochester in 1985. He then attended Columbia University, receiving the Master of Science degree in Applied Physics in 1987 under the supervision of Professor C. I<. Chu. He spent the summer of 1987 at the Los Alamos National Laboratory in association with the Center for Nonlinear Studies. In the Fall of 1987 he began doctoral study at the University of Rochester under the supervision of Professor C. J. McIGnstrie. Publications G. G. Luther and C. J. McKinstriz, "Cnopcrative Instabilities of Counterprop- agating Light Waves in Homogeneous Plasma," to be published in Phys. Rev. Lett. G. G. Luther and C. J. McKinstrie, "The Transverse Modulational Instability of Counterpropagating Light Waves," to be published in J. Opt. Soc. Am. B. G. G. Luther and C. J. hlcKinstrie, LLTransverseInstabilities of Counterpropagat- ing Light Waves," LLE Review 46, DOE/DP40200-156, 65 - 79 (1991). G. G. Luther, C. J. McKinstrie and A. L. Gaeta, LLTheTransverse Modulational Instability of Counterpropagating Light Waves," OSA Proceedings on Nonlinear Dynamics in Optical Systems, Vol. 7, Neal B. Abraham, Elsa M. Garmire, Paul Mandel, eds. (Opt. Soc. Am., Washington, D.C. 1991), pp. 205 - 209. G. G. Luther and C. J. ;V;~;Gllstrie, "Transverse Modulational Instability of Collinear Waves," J. Opt. Soc. Am. B 7, 1125 - 1141 (1990). C. J. h,IcI<instrie and G. G. Luther , "The Modulational Instability of Colinear \\'aves,!' Physica Scripta T-30, 31 - 40 (1990). C. J. llcI<instrie, G. G. Luther and S. H. Batha, "Signal Enhancement in Collinear Four-Wave Mising!" J. Opt. Soc. Am. B 7, 340 - 344 (1990). C. J. McKinstrie and G. G. Luther, "Solitary-Wave Solutions of the Generalized Three-\Yave and Four-\+"ve Equations," Phys. Lett. A 127, 14 - 18 (1988). Oral Presentations G. G. Luther, C. J. McKinstrie 2nd M. V. Goldman, "Three-Dimezsisnal In- stabilities of Counterpropagating Light Waves," Quantum Electronics and Laser Science Conference, Baltimore, Maryland, May 12 - 17, 1991. G. G. Luther, C. J. McICinstrie and M. V. Goldman, "Three-Dimensional Insta- bilities of Counterpropagating Waves," 32nd Annual Meeting of the APS, DPP, Cincinnati, Ohio, November 12 - 16, 1990. G. G. Luther, C. J. McICinstrie and A. L. Gaeta, "Transverse Modulational Insta- bility of Counterpropagating Waves and Conical Radiation, 20th Annual Anoma- lous Absorption Conference, Traverse City, Michigan, July 9 - 13, 1990. G. G. Luther, C. J. McKinstrie and A. L. Gaeta, "The Transverse Modulational Instability of Counterpropagating Waves," OSA Topical Meeting on Nonlinear Dynamics in Optical Systems, Afton, Oklahoma, June 4 - 8, 1990. G. G. Luther and C. J. McKinstrie, "Ponderomotive Filamentation in Counter- propagating Geometry," 31st Annual Meeting of the APS, DPP, Allaheim, Cali- fornia, November 13 - 17, 1989. G. G. Luther, "Ponderomotive Filamentation in Counterpropagating Geometry," Department of Mechanical Engineering, University of Rochester, October 1989. G. G. Luther, C. J. R4cICinstrie and R. It'. Short, "The Filamentation of Two Counterpropagating Waves," 19th Annual Anomalous Absorption Conference, Fort Lewis College, Durango, Colorado, June 19 - 23, 1989. G. G. Luther, ('. J. R4cKinstrie and R. W. Short, "The Filamentation of Two Counterpropagating Waves," 16th IEEE International Conference on Plasma Sci- ence, Buffalo, New York, May 22 - 24, 1989. G. G. Luther, S. H. Batha and C. J. McKinstrie, "Enhancement of the Conju- gate Signal for a Collinear Four-Wave Mixing Process," 18th Annual Anomalous Absorption Conference, l'Estkre1, Qukbec, June 26 - July 1, 1958. G. G. Luther, "Solitary- Wave Solutions of the Generalized Three- Wave and Four- IYave Equations," Applied Mechanics Seminar Series, Department of Mechanical Engineering, University aI ZULL~JLC,,October 1987. G. G. Luther, "Solitary- Wave Solutions of the Generalized Three-Wave Equa- tions," Center for Nonlinear Studies, Los Alamos National Laboratory, August 1987. Acknowledgments i owe a very special debt to all the people who have enriched and supported my education thus far. For sharing his expertise and providing patient guidance, and for his efforts as coauthor on those papers upon which this work was based, I extend my deepest gratitude to Colin McKinstrie. During my years at the University of Rochester I have been fortunate to spend many hours with Alfred Clark Jr. He has been an inspirational teacher and role model. Both my work and my graduate education has been enhanced by discussions with David Meyerhofer. For their continued enthusiasm and the support of their institutions during my graduate studies, I wish to thank Robert McCrory and Albert Simon of both the Laboratory for Laser Energetics and the Department of Mechanical Engineer- i;lg at the University of Rochester, Roger Gans of the Department of Mechanid Engineering, John Soures and Charles Verdon of the Laboratory for Laser Ener- getics, C. I<. Chu of the Department of Applied Physics at Columbia University, and David Campbell of the Center for Nonlinear Studies at Los Alamos National Laboratory. I am indebted to all the members of the staff at the Laboratory for Laser Energetics who have aided me in completing my work there. I have profited from conversations with Eduardo Epperlein, Patrick McKenty, and Robert Short. Robert Icremens and Mai Russotto have given me a peek at some of the ex- perimental aspects of inertial confinement fusion. Special thanks are due the illustration and word-processing staff for their help preparing manuscripts and conference presentations. h3y contact with members of the Institute of Optics has been invaluable. I have learned from Robert Boyd and his group. Alex Gaeta has helped make this interaction possible and has collaborated on the computational calculation of the finite-medium absolute instability thresholds. It has been a great pleasure to share parts of my graduate years with friends Pierre Basseras and Mark Arend. I owe many thanks to Bedros Afeyan. His efforts to encourage me to think more critically and his passion for physics have left an enduring impression upon me. My family has provided a stable environment that has helped sustain me. Many of the lessons learned from my grandparents have served me well during my years of graduate study; my special friend Hiram Luther has been a great inspiration. George and Jo Ann Luther, my parents, have been close friends and generous benefactors. Finally, I am fortunate to have Dana who has unselfishly shared both my moments of joy and excitement and my moments of despair. This work was supported by the National Science Foundation under Contract No. 9057093, by the United States Department of Energy Division of Inertial Fusion under Agreement KO. DE-FC03-85DP40200, and by the Laser Fusion Feasibility Project at the Laboratory for Laser Energetics, which has the following sponsors: Empire State Electric Energy Research Corporation, New York State Energy Research and Development Authority, Ontario Hydro and the University of Rochester. Such support does not imply endorsement of the content by any of the above parties. Abstract The transverse modulations: isst~bill ty (TMI), or filamentation, of two intense light waves in both finite and infinite, cubically nonlinear media is investigated using a coupled nonlinear Schroedinger-equation model. It is shown that the presence of the second laser field increases the growth rate of the filamentation instability. Systems of two copropagating waves are convectively unstable and systems of two counterpropagating waves are absolutely unstable, even when the ratio of backward- to forward-wave intensity is small. The cooperative TMI of two counterpropagating light waves is a hybrid instability caused by the inter- action of four electromagnetic sidebands and is shown to occur in the spectral overlap region of single-wave TMI, phase conjugation and Bragg scattering. This instability dominates the interaction over a significant range of pump-intensity ratios in both self-focusing and self-defocusing media. The absolute phase conju- gation instability dominaces only for small pump-intensity ratios in self-defocusing media. Having demonstrated the importance of the cooperative ThlI in nonreso- nant media, the analysis is extended to finite Brillouin-active media. This thesis provides the first unified treatment of the TR41, near-forward and near-backward stimulated Brillouin scattering of counterpropagating light waves. The cooper- ative TAII and cooperative Brillouin-enhanced four-wave mixing instabilities are shown to possess larger convective growth rates and smaller absolute instability thresholds than conventional single-pump instabilities. Either cooperative TMI or its resonantly enhanced counterparts may dominate. This analysis is consis- tent with recent experiments and suggests that cooperative instabilities may be important in applications of laser-plasma interactions. Table of Contents .. Curriculum\~itae... 111 Publications . v Oral Presentations . vii Acknowledgments. ix Abstract.