摘要
采用不同光斑直径的10．6μmCO2激光束对熔石英表面损伤进行辐照处理。实验发现，对于50μm以下的损伤点，单发激光脉冲辐照即可使得激光损伤阈值恢复到基底完好区域的水平，对于在50～300μm之间的损伤点，采用低功率较长时间辐照后逐渐增加功率修复的方式可以彻底消除材料内部更深的裂痕。对不同尺寸光斑辐照后的应力分布研究表明，激光束尺寸、激光功率和激光作用时间是影响材料体内应力分布的主要因素，相比较而言，激光尺寸对应力分布的影响更为明显。对前后表面损伤分析表明，当辐照区域置于入射面时，辐照带来的微小环状凸起会造成后表面环形调制损伤，是损伤的最薄弱环节，当辐照区域置于后表面时，烧蚀主要影响阈值的整体提升。
10.6 μm CO2 laser beams with different diameters are used to irradiate surface damage pits of fused silica. Experimental results show that a single pulse irradiation could repair damage pits below 50 μm efficiently, whose damage threshold could be recovered to the threshold of intact substrate. For damage with size between 50 and 300 μm, deep cracks could be efficiently repaired by using long time irradiation with low power laser before melting. It shows that laser power, irradiation time, and especially beam diameter are the main factors influencing the thermal stress distribution. However, pre-irradiation is in favor of melting crack in deep damage. After irradiation by 351 nm, 6.3 ns Nd： YAG laser, experimental results show that when the repair region is on the input surface, annular raised damaged region forms because of laser modulation. When the repair region is on the output surface, ablation is the main causation influencing the threshold advancement.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2011年第9期49-53,共5页
Chinese Journal of Lasers
基金
国家863计划(2008AA8040508)
国防预研基金(426020606)资助课题
关键词
激光技术
CO2激光
辐照
应力分布
损伤阈值
laser technique
CO2 laser
irradiation
stress distribution
damage threshold
