多脉冲激光对K9玻璃的表面损伤实验研究

 实验研究了波长为1 064 nm、脉宽为10 ns、重复频率为1 Hz的激光脉冲对K9玻璃的表面损伤特点，给出了脉冲透过能量随激光脉冲作用次数变化的规律。采用3维立体显微镜对损伤形貌进行观察，发现K9玻璃的损伤表面呈环状分布，分为烧蚀区、微裂纹区和断裂区。随着激光脉冲个数的增加，损伤由点状破坏演变为损伤区，微裂纹逐渐增长，损伤面积逐渐增大。基于激光支持的爆轰波理论分析，激光与脆性材料的相互作用可引起微裂纹的大量增长。在多脉冲激光的作用下，K9玻璃损伤的累积效应明显，表面损伤阈值明显降低，表面裂纹增长明显，损伤面积逐渐增大；但随着激光脉冲的继续增加，这种损伤趋于稳定。

Investigation of laser induced damage on K9 glass surface using multi-pulse laser

Experimental study of characteristics of laser induced damage on the K9 glass surface,irradiated by Nd∶YAG laser operating at 1.064 μm wavelength and approximately 10 ns pulse duration and 1 Hz repetition rate,have been made. The change law of laser pulse output energy versus the repeat number of laser shots was investigated. Stereo microscope was employed to observe laser induced damage morphology after sigle-shot and multi-shot laser irradiation. The ripple damage on the K9 glass surface could be obviously observed,and the failure surface can be devided into three parts: ablation zone,microcrack zone and brittle fracture zone. After the first shot small damage spots appeared on the K9 glass surface;after multi-shot irradiation,microcracks and damage area increased gradually with the number of shots. Based on the laser-supported detonation wave theory,the interaction of high-intensity laser with K9 glass can induce a lot of microcracks in brittle material. Accumulation of multi-shot laser induced damage in K9 glass is obvious,the laser induced damage threshold of K9 glass surface is distinctly reduced,and the growing of microcrack zone and damage area are remarkable.