真空环境下光学薄膜的激光损伤

Laser-induced damage of optical films in vacuum environments

利用1-on-1损伤测试方法,比较研究了电子束沉积制备的几种薄膜在真空、大气环境下的损伤特性,并对真空环境与大气环境损伤的差异进行了分析。研究结果显示:真空环境下的损伤阈值明显低于大气环境下的损伤阈值,真空环境下的破斑形貌也与大气环境下的破斑形貌有显著差异。气体热传导差异不是真空环境与空气环境下损伤差异的原因。由水的解吸而引起膜层在真空环境中张应力的增大及真空环境中激光辐照过程中产生的非化学计量比缺陷是导致电子束沉积的薄膜真空与大气环境中损伤差异的原因。

Characteristics of laser-induced damage of some optical thin films deposited by e-beam evaporation were investigated in vacuum and atmosphere environments,and the differences of laser-induced damage in two conditions were analyzed and discussed.The results show that compared to normal atmospheric conditions,optical thin films have a decreasing laser induced damage thresholds under vacuum environments.The morphologies of the damages under two conditions are quite different.Gas heat conduction has little influence on the difference of damage thresholds under two conditions.The hydrolysis-induced tension increase and the laser-irradiated nonstoichiometric defects of films in vacuum environments probably result in different laser-induced damages in vacuum and atmosphere environments.