光斑尺寸对光学薄膜元件温升的影响

 实验测量了波长1 064 nm， 10 kHz高重复频率激光辐照下在白宝石、石英玻璃、K9基片上制备的Ta₂O₅/SiO₂高反膜的温度变化，有限元分析的结果与实验结果相一致。用ANSYS程序计算了不同光斑直径、相同功率激光和相同功率密度激光辐照下薄膜元件温升的变化。结果表明：相同功率激光辐照光学薄膜元件时，光斑大小只影响激光辐照点的温升，对基板温升没有影响。基板温升只与激光功率有关，激光功率越大，基板温升越大。相同功率密度激光辐照光学薄膜元件时，光斑越大，激光辐照点温度及基板温度均越高。从激光损伤的热效应考虑，小光斑激光辐照时，光学薄膜的激光损伤阈值较高。

Laser beam diameter effect on temperature rise of films

Experiments have been performed to measure the temperature rise of Ta2O5/SiO2 multilayer coatings with substrate sapphire,fused silica and K9 at repetition rate 10 kHz,1 064 nm pulse laser.Results calculated by ANSYS agree well with the experiment data.The maximal temperature of films irradiated by the same power density or power but different facula was calculated.The results indicate that,when irradiated by the same power laser,the size of laser facula can affect the temperature rise of films only;the temperature rise of substrate only depends on the laser power.The laser power increases,the temperature rise of substrate increases.However,when films are irradiated by the same power density laser,with the size of laser facula increases,the maximal temperature of films and substrate increase.Considering the thermal mechanism,when irradiated by smaller laser facula,the laser-induced damage threshold of films will be higher.