经355nm激光预处理后熔石英的损伤增长

Growth of Laser Initial Damage in Conditioned Fused Silica at 355 nm

为研究经预处理的熔石英损伤点随激光脉冲的增长关系,采用355 nm脉冲激光辐照预处理熔石英,再辐照位于后表面的损伤点,然后用Mias软件采集损伤增长的图像并测量每次脉冲后损伤点的面积。通过与未经预处理熔石英的损伤增长相比较可得出,经预处理与未经预处理的熔石英损伤点面积均随激光辐照脉冲数呈指数增长,但前者的损伤增长速度比后者的快。355 nm激光预处理能够有效提高熔石英元件的抗损伤阈值,但损伤一旦发生将会更加快速地扩展。

In order to investigate the relation between growth of fused silica initial damage and numbers of laser pulse,the damage sites located on exit surface of conditioned fused silica were irradiated with 355 nm pulse laser.After each shot,photograph of growth of the damage site was taken and the area of the damage site was measured.By comparing with the case of growth of unconditioned fused silica damage sites,experimental results show exponential growth in the lateral size of damage sites located on exit surface with shot number in both the case of conditioned and the case of unconditioned,whereas the growth of conditioned silica damage sites are more rapid than the growth of unconditioned silica damage sites.Laser condition can effectively improve laser damage threshold,but it can reduce resistance of fused silica to damage growth.