1064nm激光多脉冲下HfO2/SiO2高反膜损伤规律

利用小口径元件损伤测试平台对HfO2/SiO2高反膜的1 064 nm激光多脉冲损伤规律进行了研究。研究结果表明:多脉冲作用下HfO2/SiO2高反膜损伤在形态上主要分为色斑和层裂两类,在一定条件的多发次脉冲作用下,色斑损伤存在向层裂损伤转换的趋势;层裂损伤尺寸随脉冲发次呈指数递增后趋于极大值的变化规律,且终态尺寸与辐照激光能量密度呈近似线性关系;色斑S-on-1损伤阈值与脉冲发次关系不明显,而层裂S-on-1损伤阈值随脉冲发次增加呈指数衰减后趋于极小值的变化规律。采用衰减公式拟合手段,对元件抗损伤能力退化规律进行了初步的定量分析。

Studies of multipulse laser induced damage of HfO2/SiO2 multilayer at 1064 nm

Multipulse laser induced damage properties of the hafnia-silica mirror were studied by the use of small optic damage test facility.The results of the test indicate that there are two commonly damage morphologies at vacuum,scalds and delaminates,and the scalds will expand to delaminates under multipulse with a certain fluence.The lateral size of layer delamination shows an exponential growth behavior with the initial shots and finally tends to be stable.The final size of delaminate after 500 shots has a linear function of the laser fluence.The experiment result also indicates that scalds and delaminates have distinct growth behaviors and influence the value of S-on-1 damage threshold differently.Scalds has a lower S-on-1 damage threshold which is stable as the shot number.In contrast,delaminates′ multipulse damage threshold shows an exponential in the much higher onset fluence with an asymptotic behavior apparently at large shot numbers.Finally a simple function for fitting the decay law of damage threshold and the quantitative analysis of optic life such as hafnia-silica mirror was discussed.