不同周期膜系结构对1064nm高反膜的激光损伤阈值的影响

Influence of Multilayer-Sequence on Laser-Induced Damage Threshold of High Reflective Films at 1064 nm

基频高反膜元件由于较易受到激光损伤而严重影响激光系统正常工作,因此研究高反膜的激光损伤原因及损伤机理成为一个急需解决的问题。本文搭建激光损伤阈值测试平台,对不同周期膜系结构的1064 nm激光高反膜的激光损伤阈值的影响进行了研究。研究结果表明,相比较于G｜（LH）^9L｜A膜系,G｜（HL）^9L｜A这种周期结构的薄膜的激光损伤阈值较高,且损伤形貌以熔融型为主。

The damages of high reflective multilayered thin films（TiO_2/SiO_2） grown on Bk7 and Si substrates,induced by laser irradiation,were empirically approximated,mathematically modeled,theoretically analyzed in thermodynamics/electrodynamics,and experimentally evaluated with the lab-built platform.The influence of the multilayers ＇ properties,including but not limited to the multilayer-sequence,surface roughness,and reflective index of materials,on the laser-induced damage threshold（LIDT） at 1064 nm was investigated.The calculated and measured results show that the multilayer sequence significantly affects the LIDT of the multilayer.To be specific,the G｜（HL）~9L｜A multilayer,where G and A stand for substrate and air;H and L denote the quarter-wavelength layers with high（TiO_2） and low（SiO_2） reflective indexes,respectively,has higher ODT than G ｜（LH）~9 L ｜ A;and the melting damage dominated.Possible mechanisms responsible for the observation were also tentatively discussed in a thought provoking way.