Numerical study on SBS process in fused silica glass under focal pumping

Taking account of spatial dependence in the propagation direction of focused laser beams, the SBS process in fused silica glass is simulated numerically. The dependence of pump energy on SBS reflectivity is presented, which shows good agreement with Yoshida's experiment results. The "focused spike" in scattering pulse is observed theoretically and the influence of SBS on optical damage, under focusing condition, is discussed. The simulation shows that under the condition of focal pumping the presence of SBS would strongly limit the amplitude of stress induced by single longitudinal laser.