Time compression of pulses in the course of stimulated Brillouin scattering in gases

Theoretical and experimental investigations were made of the feasibility of effective time compression of light pulses as a result of stimulated Brillouin scattering of a light beam in gases. An optimal focusing geometry and a specific excess above the scattering threshold made it possible to achieve time compression by a factor of 20–30 and the duration of the Stokes pulse was then an order of magnitude less than the decay time of hypersound. Stimulated Brillouin scattering in argon at various pressures, corresponding to relaxation times in the range from 1 to 8 nsec, was used to convert pump pulses of 20 nsec duration into Stokes pulses of 1 nsec duration. The energy efficiency of the process was in excess of 80% and the angular divergence was not affected.