Stimulated Brillouin scattering in plastics

Abstract
Hypersound speeds, the power threshold for stimulated Brillouin scattering (SBS), steady‐state and transient gains for SBS, and the phonon lifetime have been studied in the plastics of polymethylmethacrylate and polyethylmethacrylate as a function of temperature. Damage thresholds were investigated and the effects of annealing are discussed. An extension of current theory allows a determination of phonon lifetimes and relative gains to be determined without absolute calibration of the laser power.