Al基反射膜的激光损伤阈值研究

tudy on Laser induction damage threshold of Al-based reflective films

为研究金属Al保护、单周期及双周期增强反射膜在5ns脉宽的532nm激光器下的激光损伤阈值(LIDT),采用Comsol软件进行仿真及分析,仿真过程引入SiO2和Ta2O5的拉伸强度(膜层断裂应力)作为阈值条件,得到三种膜系的损伤阈值分别为0.318J/cm^(2)、1.325J/cm^(2)和3.382J/cm^(2),通过搭建实验平台进行激光阈值测试,采用1-on-1模式,选取50%概率的激光损伤点作为损伤阈值,测得激光功率分别为0.288J/cm^(2)、1.232J/cm^(2)及3.152J/cm^(2),与仿真结果较为接近,说明采用拉伸强度分析的该类模型更符合实际损伤,为此类膜系在实际应用中阈值的预测提供了理论基础。

In order to study the laser induction damage threshold(LIDT)of metal Al-protected,single-period and double-period enhanced reflective films under 532nm laser with 5ns pulse width,Comsol software is used for simulation and analysis.The tensile strength(film breaking stress)of SiO2and Ta2O5are introduced as the threshold condition in the simulation process,and the damage threshold values of three film systems are 0.318J/cm^(2),1.325J/cm^(2)and 3.382J/cm^(2)respectively.By building an experimental platform to test the laser damage threshold,the 1-on-1mode is adopted,and the laser damage point with a probability of 50%is selected as the damage threshold.The results of measured laser power are 0.288J/cm^(2),1.232J/cm^(2)and 3.152J/cm^(2)respectively,which are close to the simulation results,indicating that the model based on tensile strength analysis is more in consistent with the actual damage,which provides a theoretical basis for the prediction of the threshold value of this kind of film system in practical application.