利用染料片吸收控制受激布里渊散射功率限幅波形

理论研究了受激布里渊散射过程中功率限幅响应特性.采用高斯型入射脉冲，数值模拟了抽运参数(抽运峰值功率密度、抽运脉冲宽度)，介质参数(增益系数、声子寿命)和结构参数(聚焦透镜焦距、介质池长)等物理参数影响限幅输出波形中剩余峰的特性规律.对如何控制剩余峰进行了理论分析.研究表明，声子寿命较小、增益系数大的布里渊介质光限幅响应较好，声子寿命较大、增益系数小的布里渊介质光限幅响应较差；无法单纯通过控制布里渊介质参数来完全消除剩余峰.实验上采用染料片吸收剩余峰，获得接近平顶的限幅输出波形.

Controlling the optical limiting shape in stimulated Brillouin scattering by dye absorption

On the basis of computing models of stimulated Brillouin scattering (SBS), the optical limiting response characteristics in SBS process are investigated theorctieally. Dependence of limiting parameter ——residual energy on pump parameters (input power density, pulse duration), medium parameters (gain, phonon life time) and configuration parameters (focusing length, cell length) are analyzed. Response characteristics of SBS limiting are given by studying the variation of delay time, residual peak power and residual energy. Ideal response system can be obtained by choosing a medium with larger gain and shorter phonon life time. But the vesidual energy could not be got rid of by choosing SBS medium parameters only. In experiment, we obtained flat-roofed optical limiting pulse shapes in SBS process using dye absorption.