UBK7玻璃后表面缺陷诱导体内激光损伤

 对UBK7玻璃在波长为1.064靘的短脉冲激光作用下产生的损伤进行了研究。通过对体损伤的形貌的相衬显微镜观测，发现体内和后表面炸裂点间的丝状损伤，从而提出后表面缺陷导致体损伤的理论解释。同时分析了表面损伤和体损伤的机理，对后表面损伤阈值低于前表面的原因作了讨论。

Laser-induced bulk damage of UBK7 glass owing to its rear-surface defects

Pulsed laser induced bulk damage of UBK7 glass at 1064nm was studied. Damage morphologies of UBK7 were observed with a microscope. Laser induced damage thresholds(LIDT) of the glass's surface and bulk were tested using automated damage test facility. Thread damage between rear surface and bulk burst was detected from the damage morphologies. The conclusion that defects and impurities on the rear surface caused bulk damage was drawn. When the defects on rear surface absorb incident light, plasma was produced and it spread to the front rapidly. Then the high temperature and high pressure of the plasma caused surface and bulk damage of the material. The details of surface and bulk damage mechanism were also analyzed. The LIDT of rear surface is lower than that of front surface because of the light intensity modulations caused by opaque obstacles on the front. The decrease of defects on surface can not only increase surface damage threshold but also improve bulk damage threshold.