后向受激布里渊散射诱导的光学材料破坏机理研究

 区别于传统的受激布里渊散射(SBS)发生器和放大器，提出了一种新型的SBS模型：自供种子光模型 (self Stokes seeding，SSS)。数值求解了SBS耦合波方程组，得到了SBS诱导应力的时空分布。基于SSS建立了高功率激光辐照下光学材料破坏阈值的计算模型，研究了SBS破坏阈值与激光脉宽以及作用区长度的关系。研究发现，SBS作为一种破坏机制，表现为前表面破坏，且破坏阈值与激光脉宽以及作用区长度均成反比。

Theoretical study on damage induced by stimulated Brillouin scattering process

A new SBS model, which is described as self stokes seeding (SSS), is brought forward and its mechanism is researched. The SBS coupled wave equations are solved numerically and laser induced stress is obtained spatially. Theoretical model is established to study the damage process inuced by SSS process and damage thresholds are calculated. Physical chracteristics which should be embodied by SBS damage mechanism are analyzed, and the dependence of laser pulse width and interaction length on damage thresholds is presented. The theoretical research shows that the SBS induced damage mostly happens at the entrance surface of pump laser and the threshold intensity is inversely proportional to laser pulse width and the interaction length.