Observation of relativistic cross-phase modulation in high-intensity laser-plasma interactions

Authors

Shouyuan Chen, University of Nebraska - LincolnFollow
Matthew Rever, University of Nebraska - LincolnFollow
P. Zhang, University of Illinois, Chicago, Illinois
W. Theobald, University of Rochester, Rochester, New York
Donald Umstadter, University of Nebraska-LincolnFollow

Date of this Version

10-18-2006

Comments

Published by American Physical Society. Phys. Rev. E 74, 046406 2006. http://pre.aps.org. Copyright © 2006 American Physical Society. Permission to use.

Abstract

A nonlinear optical phenomenon, relativistic cross-phase modulation, is reported. A relativistically intense light beam (I=1.3×10¹⁸ W cm^-2, λ =1.05 μm) is experimentally observed to cause phase modulation of a lower intensity, copropagating light beam in a plasma. The latter beam is generated when the former undergoes the stimulated Raman forward scattering instability. The bandwidth of the Raman satellite is found to be broadened from 3.8–100 nm when the pump laser power is increased from 0.45–2.4 TW. A signature of relativistic cross-phase modulation, namely, asymmetric spectral broadening of the Raman signal, is observed at a pump power of 2.4 TW. The experimental cross-phase modulated spectra compared well with theoretical calculations. Applications to generation of high-power single-cycle pulses are also discussed.