CW (Continuous Wave) Stimulated Brillouin Scattering of Long-Pulse Chemical Laser Beams

Backward Stimulated Brillouin Scattering SBS is currently under consideration as a nonlinear optical process for passive phase conjugation beam clean up phase matching beam combination, and pointing and tracking of continuous-wave CW HF chemical lasers for high power applications. Theoretical considerations indicate, however, that forward SBS processes dominate over backward SBS phenomena in the steady-state limit, so that SBS exhibits the desired properties phase conjugation only for short time periods. Since backward SBS thresholds for CW HF lasers are about 0.20 MW per spectral line, long-pulse laboratory chemical laser sources PCLs are needed to investigate small-angle forward scattering phenomena and the development of techniques for their suppression. The laser data presented herein suggest that a moderate- volume, photolysis-pumped PCL is a suitable source for the study of steady-state forward SBS processes and their suppression. In particular, low pressure PCLs can simulate CW HF-laser SBS behavior under conditions of the proper bandwidth, laser spectrum, SBS media effects, longitudinal mode structure, and other high-power HF laser characteristics.