Measuring specific amplification coefficient for stimulated Brillouin scattering of radiation in glasses used in optical channel of powerful lasers

This work presents a method for determination of specific amplification coefficient for stimulated Brilloin scattering (SBS) of radiation based on measuring amplification of the Stokes signal in a medium sample used as the SBS-amplifier. Registration of spatial distributions of amplified beam intensity allows minimization of a measurements error caused by saturation of Stokes radiation amplification in the sample under study. Values of specific amplification coefficient for SBS of radiation are obtained under identical experimental conditions for new phosphate glass KGSS 0180 (g = 1.9 cm/GW) and for glasses widely used in laser systems: GLS 22 (g = 1.4 cm/GW) and K 8 (g = 1.3 cm/GW). By means of optical heterodyning of radiation a SBS-frequency shift of laser radiation at a wavelength of 1.054 microns is measured for new glass KGSS 0180 (u v = 14.57± 0.02 GHz). It makes it possible to estimate hypersound propagation velocity in the tested glass (V ≈ 5030 m/c) at this frequency.