激光聚焦到受激布里渊散射(SBS)介质中所产生的声子光栅的密度对比度对应于叠加光场的强度对比度, 据此直观分析了宽线宽激光SBS能量阈值高于窄线宽激光SBS的原因, 并对宽线宽SBS相位共轭谐振腔的高启动阈值进行了定性分析。设计并运行了CrLiSAF宽线宽SBS相位共轭激光器, 对其静态运行时的输出激光波形, 以及自调Q动态运行时的输出激光脉冲波形、能量、光束发散角等进行了测量。结果表明它能有效地产生脉宽约为50 ns的自调Q脉冲激光, 光束发散角相对于静态激光压缩了约2倍。

Laser beam focused on stimulated Brillouin scattering (SBS) medium can produce phonon grating, whose density contrast direct ratio to superposition fringe intensity contrast of light field. Then the reason of broad-band laser SBS having higher energy threshold than narrow-band SBS is analyzed, and the qualitative analysis of broad-band SBS phase-conjugation laser resonator having higher startup energy threshold is given. A broad-band SBS phase-conjugation laser resonator of CrLiSAF is designed and operated, its free-running output laser pulse waveform, self-Q-switching output laser pulse waveform, pulse energy and beam divergence angle are measured. The results indicate that this resonator can produce 50 ns self-Q-switching narrow pulsewidth laser beam efficiently, its beam divergence angle is compressed by a factor of two.