激光与材料参数对瞬态SBS诱导的激光超声破坏效果的影响

Influence of pulse duration and interaction length on transient SBS induced damage

通过数值求解一维瞬态受激布里渊散射(SBS)声光耦合波方程,从理论上分析了泵浦激光参数及光学材料参数对SBS过程发生阈值的影响。以SBS过程中建立起来的应力场抗拉(压)强度和散射场的反射率为判据,分析了激光脉宽及作用区域长度对激光超声破坏材料效果的影响,探讨了短脉冲激光(约ns)引起的激光超声对材料的破坏机理;讨论了通过参数配置有效遏制SBS过程激光超声对光学材料的破坏问题。

Transient Stimulated Brillouin Scattering (SBS) coupled equations are solved for one-dimension approximation. Through numerical study, dependence of influence induced by SBS procession on parameters of laser and medium is investigated respectively. The relationship between pulse duration, interaction length and the damage threshold is discussed in terms of the stress and reflectivity built in SBS procession. Find out a better configuration of parameters to restrain the damage induced by SBS procession. We can get the conclusion that temporal variation of stree field in the SBS medium with different size follows the same rule when interaction length is less than some value; a greatest interaction length which SBS medium is easy to be damaged is existent; and we also find that we can obtain high power laser which has much shorter pulse duration through SBS pulse compression.