酸蚀深度对熔石英三倍频激光损伤阈值的影响

 采用干涉仪和台阶仪测试蚀刻深度随时间的变化，结合材料去除速率测量，研究了HF酸蚀液对熔石英表面蚀刻的影响。测试了蚀刻后损伤阈值和表面粗糙度的变化。研究表明，熔石英表面重沉积层厚度约16 nm，亚表面缺陷层大于106 nm；重沉积层去除后损伤阈值增大，随亚表面缺陷层暴露其阈值先降低后又增加，最后趋于稳定；然而，随蚀刻时间的增加，其表面粗糙度增大。分析表明，蚀刻到200 nm能有效地提高熔石英的低损伤阈值，有利于降低初始损伤点数量和提高熔石英表面的机械强度。

Effects of acid-etching depth on 355 nm laser-induced damage threshold of fused silica

The effects of chemical etching with a buffered HF solution on fused silica surface were studied by measuring the etched depth, via interferometer and step meter, and etched material mass under different etching time. The depth etching rate and material removal rate became constant after about 8 min etching. The redeposition layer of optical polished surface was about 16 nm, while the subsurface defect layer was deeper than 106 nm. The laser-induced damage threshold and surface roughness before and after chemical etching were also measured. The results showed that, firstly, the damage threshold increased with the removal of the redeposition layer. Then, it decreased with the exposure of the subsurface defects followed by an increase with the increase of etching time. Finally, it was almost