多层介质高反膜界面电场强度调控与光散射特性  

Regulation of Electric Field Intensity at Interface and Light Scattering Characteristics of Highly Reflective Multilayer Dielectric Films

作　　者：杨伟荣 潘永强[1] 郑志奇 Yang Weirong;Pan Yongqiang;Zheng Zhiqi(School of Optoelectronic Engineering,Xi'an Technological University,Xi'an,Shaanxi 1\002\,China)

机构地区：[1]西安工业大学光电工程学院,陕西西安710021

出　　处：《中国激光》2022年第6期16-22,共7页Chinese Journal of Lasers

基　　金：陕西省教育厅重点实验室科研计划项目(18JS054)、陕西省自然科学基础研究计划项目(2018JM6031)。

摘　　要：为了降低高精密使用场合下多层介质高反射薄膜的表面散射,首先从多层介质薄膜双向反射分布函数(BRDF)出发,理论分析了双向反射分布函数与薄膜界面电场强度的关系。在入射光为正入射且中心波长632.8nm处的反射率大于99%的要求下,采用SiO_(2)、Ta_(2)O_(5)两种材料设计了膜系G/(HL)8/A和膜系G/(HL)8 H/A,并分析了两种膜系界面的电场强度分布。然后以膜系G/(HL)8 H/A界面的电场分布为基础对场强进一步优化,得到了膜系G/(HL)60.4L1.6H1.5L0.5H/A。理论计算了正入射条件下三种膜系的双向反射分布函数,发现当散射角为-45°~45°时,膜系G/(HL)6 H0.4L1.6H1.5L0.5H/A表面的BRDF小于膜系G/(HL)8/A和膜系G/(HL)8 H/A。同时计算了三种膜系表面的总散射损耗(S),与膜系G/(HL)8/A和膜系G/(HL)8 H/A相比,优化膜系G/(HL)6 H0.4L1.6H1.5L0.5H/A的S降低了91.44%、37.98%。实验验证了利用膜层界面电场强度调控薄膜表面散射的有效性。Objective Scattering of optical elements in high-precision optical instruments is an important factor influencing the use of instruments.For example,because the gain coefficient of the high mirror in the laser gyro system is relatively low,which requires the system to have extremely high reflectivity,the surface scattering of the high mirror hinders the further improvement of the reflectivity of the mirror.Thus the loss on the high mirror in the resonant light path has an important influence on the determination of the locking threshold of the laser gyro.Another example is the high reflective film in the lithography system.In order to ensure the high resolution and efficiency of the lithography system,it is necessary to require a very low optical loss of the high reflective film.In high-energy laser system,the laser output can be greatly increased by increasing the reflectivity of the high mirrors in the resonant cavity,and the low scattering loss can make the system get a better beam quality.The study on the surface scattering characteristics of optical thin films is not only beneficial to the preparation of high-performance optical thin film devices,but also can be used to detect the laser damage threshold of optical thin films according to their surface scattering characteristics.How to reduce the scattering loss of high mirrors in high-precision instruments is a big problem that puzzles optical film designers.A large number of scholars at home and abroad have done a lot of detailed researches.Most researchers have focused on reducing the roughness of the multilayer film interface from the perspective of coating process and have made a lot of research results.However,reducing the roughness of the multilayer film interface by regulating the coating process has reached a certain limit.If we want to further reduce the roughness,we need to pay a huge price,thus it is urgent to acquire a new method to reduce the surface scattering of multilayer optical films.Methods In this paper,based on the vector scattering theo

关 键 词：薄膜 多层设计 光散射 双向反射分布函数 总散射损耗 

分 类 号：O484[理学—固体物理]