退火参数对熔石英透射波前和损伤阈值的影响

 采用高温退火技术去除熔石英元件表面由于CO2激光修复带来的残余应力，研究了退火环境对元件的表面污染，分析了不同退火温度（600～900 ℃）和保温时间（3～10 h）对于元件残余应力、透射波前、表面粗糙度和激光损伤阈值的影响。结果表明:在800 ℃以下,高温退火10 h可有效去除CO₂激光修复带来的残余应力，对元件的透射波前和表面粗糙度无明显影响;石英保护盒能有效减少退火环境对元件表面产生的污染，但仍有X射线光电子能谱检测不到的表面污染物存在;在退火后采用质量分数为1%的HF刻蚀15 min，激光损伤阈值可恢复，同时元件透射波前和表面粗糙度并无明显的增加。

Effects of annealing parameters on transmission wavefront and damage threshold of fused silica

Thermal annealing at high temperature is used to relieve the residual stress of fused silica induced by CO2 laser repair. The effects of annealing environment on surface contamination of fused silica as well as the effects of different annealing temperatures (600 to 900 ℃) and time (3 to 10 h) on residual stress, transmission wavefront, surface roughness, and laser induced damage threshold (LIDT) are investigated. The results show that the residual stress induced by CO2 laser repair can be effectively relieved after annealing at 800 ℃ for 10 h and there is no obvious change in the wavefront and surface roughness of optics. A silica shield box can reduce surface contamination from annealing environment but there are still some contaminations undetectable for X-ray photoelectron spectrosco