激光诱导HF酸刻蚀后熔石英后表面划痕的损伤行为研究

用光学显微镜和原子力显微镜记录HF酸刻蚀后熔石英元件后表面划痕的形貌结构,并利用单脉冲激光对其进行辐照测试,以研究不同结构参数划痕的激光损伤特性.实验结果表明,由于HF酸的腐蚀钝化作用,划痕结构横向截面呈余弦形分布;其初始损伤阈值并非由单一的划痕宽度或深度参数决定,而是与其横向剖面结构的宽深比值密切相关;通过实验得到了二者之间的关系曲线,并采用时域有限差分算法对不同结构参数划痕附近光场分布进行理论模拟,理论场计算得到的增强结果与实验值符合得很好.

Laser induced rear-surface-crack damage properties of fused silica etched with HF solution

The micro subsurface cracks of fused silica etched with HF solution were recorded using atomic force microscope (AFM) and optical microscope. The damage characteristics of cracks with different structures were studied. Experimental results show that after HF etching, the cracks cross section turns into cosine pattern, and its laser induced damage threshold (LIDT) is not determined by the individual breadth or depth parameters, but by the breadth depth ratio of the crack cross section. The curve of LIDT versus the cracks breadth depth ratio was experimentally obtained. Finite difference time domain algorithm was used to calculate the electric field intensity distribution in the vicinity of a crack with cosine cross section, and the theoretical results agree well with the experimental ones.