一种大入射角容差宽带薄膜偏振器

A broadband thin-film polarizer with large angle tolerance

通过组合长波通和短波通膜堆的方法,设计并制备了一种大入射角容差宽带薄膜偏振器。该薄膜为HfO_2/SiO_2结构,采用无离子束辅助的电子束蒸发工艺,蒸发金属铪和SiO_2制得。对该膜的透射率光谱、激光损伤阈值和形貌进行了研究,结果显示其不仅在1044~1084 nm波段内都具有很高的对比度,而且在1064 nm波长、53°~60°的入射角范围内具有很大的消光比和激光损伤阈值,且损伤特性基本不随入射角变化。该偏振器的P光损伤阈值约为20 J/cm^2,损伤主要由基板与薄膜界面处的纳米级缺陷所引起;S光损伤阈值约为45 J/cm^2,损伤主要由激光辐照下薄膜表面的等离子烧蚀现象引起。

A kind of broadband thin film polarizer with large angle tolerance has been designed and fabricated. This polarizer has high extinction ratio in the incidence angle range of 53°-60°and wavelength region of 1044-1088 nm. The coating design is H/ L type multilayer, and employs HfO2 and SiO2 as the high and low refractive index materials. The electronic beam evaporation method is employed to evaporate the metal hafnium and SiO2 without ion beam assistance. Laser damage characteristic is investi- gated. The results show that the laser induced damage threshold （LIDT） of the P polarization is 20 J/cm , and the relevant dam- age morphology indicates that the damage is initiated from nanosize absorbers located at the coating and substrate interface or and the damage is initiated from nodules or contamination patti