采用电子束蒸发沉积技术制备了平板偏振膜。用Lambda900分光光度计测试了其光学性能。在中心波长1053 nm处P偏振光的透过率TP>98%,S偏振光的透过率TS<0.5%,消光比TP/TS>200:1,带宽约为20 nm。用波长1064 nm,脉宽12 ns的脉冲激光进行损伤阈值测试,获得P偏振光的损伤阈值为17.2 J/cm2,S偏振光的损伤阈值为19.6 J/cm2。用Nomarski显微镜对薄膜的损伤形貌进行观察,并用Alpha-500型台阶仪对损伤深度进行测试。结果表明, P偏振光的激光损伤为界面损伤与缺陷损伤,而S偏振光的激光损伤主要是驻波电场引起的界面损伤,界面损伤发生在偏振膜表面第一层与第二层界面处,缺陷损伤发生在偏振膜内部。

The flat polarizer was prepared by electron beam evaporation and its optical performance was measured by Lambda900 spectrometer. The transmission of P-polarization is more than 98%, the transmission of S-polarization is less than 0.5%, its extinction ratio is more than 200:1, and its spectral bandwidth is 20 nm near 1053 nm. The laser-induced damage thresholds (LIDTs) of P-polarization and S-polarization are 17.2 J/cm2 and 19.6 J/ cm2, respectively, measured at 1064 nm wavelength,12-ns pulse width and the incident angle of 60°. The morphology of the laser-induced damage was characterized by Nomarski microscopy and its depth was measured by Alpha-500 step meter. Two distinct damage morphologies (defect and delamination) were observed when polarizer was tested in P-polarization. The character of interface caused the outer layer delamination damage morphology and which happened at hafnia-silica interface of the outer layer. The defect damage was induced by the defects in the film, and it appeared in the interior of the polarizer. In the case of S-polarization,the outer layer delamination damage morphology,which was induced by standing electric field was also observed.