纳秒激光诱导损伤熔石英玻璃的动力学过程

Dynamic process of nanosecond laser damage of fused silica

采用超快时间分辨阴影成像技术研究了纳秒激光诱导损伤熔石英玻璃前后表面和体内的动力学过程,对比分析了前后表面和体内的损伤差异及损伤机制。在前表面,观察了空气和材料中的等离子体和冲击波的产生与发展过程;亚纳秒激光辐照下,前表面材料内观察到三个应力波,并观察到材料体内的损伤过程。在后表面,除观察到冲击波的产生与发展过程,还观察到表面物质的烧蚀去除与喷发过程。在材料内部,损伤由自聚焦和点缺陷吸收两种机制主导,而且点缺陷吸收诱导材料体内损伤有时间先后顺序。

The dynamic process of nanosecond laser induced damage of fused silica＇s input-surface,output-surface and bulk in air was investigated by ultrafast time-resolved shadowgraphs.The comparison and analysis of the damage mechanisms of the input-surface,output-surface and bulk were performed.On the input-surface,the generation and development process of plasma and shock wave were observed in air and materials,three stress waves were observed in materials under the subnanosecond laser,and the bulk damage was observed near the input-surface.On the output-surface,the images of material ablation,explosive phase change and shock waves were obtained.In the bulk,the results show that both the self-focusing and the absorption of point defect are answerable for the damage.However,the damage beginning due to the absorption of point defect maybe has temporal difference.