激光钝化对熔石英修复后损伤性能影响的实验研究

采用10.6 μupm 的 CO₂激光, 对单次激光脉冲辐照修复熔石英存在的烧蚀采用大光斑钝化去除. 经过辐照修复的区域置于前表面测试初始损伤阈值, 结果表明调制造成的损伤得到了一定程度的抑制; 辐照区域置于后表面修复后 熔石英的初始损伤阈值超过了基底的初始损伤阈值. 实验观察到了应力分布外扩, 同时明显减弱. 对损伤增长的测试说明, 经过激光熔融辐照后的损伤点, 当应力释放以后, 损伤扩展初期表现出指数增长趋势, 后期随着辐照次数的增加, 损伤增长不再明显, 并且趋于恒定值.

Influence of laser passivation on fused silica damage after CO2 laser mitigation

A 10.6μm CO₂ big size laser beam is used to passivate the ablation deposit on surface of damage site which is repaired with single laser pulse.When the irradiated region is placed on front surface,modulation by 355 nm UV ns laser pulse is inhibited effectively; when the irradiated region is situated on rear surface,the initial damage threshold exceeds the substrate initial damage threshold. Second repair makes the thermal stress distribution enlarged obviously and the thermal stress magnitude weakened.The damage growth examination shows that once thermal stress is released,the initial phase damage growth exhibits an exponential tendency and as shoot number increases the damage size approaches to a constant value.