长脉冲激光损伤YAG晶体的研究

Analysis of YAG Crystal Damage Induced by Long Pulse Laser

采用毫秒Nd∶YAG脉冲激光在不同的保护气体作用下对钇铝石榴石(yttrium aluminum garnet,YAG)晶面单脉冲损伤及多脉冲切割进行了研究,激光损伤及切割断口形貌采用SEM进行表征。结果表明:单脉冲TEM00模式Nd∶YAG激光对YAG晶体损伤时,表面能够生成锥形烧蚀坑(钥匙孔),且烧蚀坑的熔融层约几个微米;毫秒多脉冲Nd∶YAG激光在Ar,N2,O2保护下切割YAG单晶体,切割深度与保护气第一电离能相关。切割状态下,断口出现爆沸现象,产生的气泡形貌与保护气氛有关。

Single pulse damage and multi-pulse cutting yttrium aluminum garnet （YAG） by millisecond Nd ： YAG pulse laser were investigated. Morphology of laser damage and cutting fracture were characterized by scanning elec- tronic microscope （SEM）. The result shows that ablation hole （keyhole） is formed by single pulse TEM00 mode Nd ： YAG laser,and the thickness of molten layer of ablation hole is about several micrometers; cutting depth of YAG single crystal is related with the first ionic energy of shielding gas and micro-morphologies of their cutting frac tures differ prominent under Ar,N2·O2 by multi pulse ms Nd ： YAG laser. In cutting condition, explosive boiling takes place within cutting kerr,and the morphologies of bubbles changes with shielding gas atmosphere.