基于蓝宝石材料的微结构增透性能研究  

Study on Microstructure Anti-reflection Performance Based on Sapphire Material

作　　者：张文妮 曹红超[1,3] 孔钒宇[1,3] 张益彬 汪瑞 晋云霞[1,3,4] 邵建达 Zhang Wenni;Cao Hongchao;Kong Fanyu;Zhang Yibing;Wang Rui;Jin Yunxia;Shao Jianda(Laboratory of Thin Film Optics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Materials for High Power Laser,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;CAS Center for Excellence in Ultra-Intense Laser Science,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]中国科学院上海光学精密机械研究所薄膜光学实验室,上海201800 [2]中国科学院大学材料与光电研究中心,北京100049 [3]中国科学院上海光学精密机械研究所强激光材料重点实验室,上海201800 [4]中国科学院超强激光科学卓越创新中心,上海201800

出　　处：《中国激光》2023年第22期63-71,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2020YFA0714500);国家自然科学基金(61875212,U1831211);上海市战略性新兴产业发展专项基金(31011442501217020191D3101001);中国科学院国际合作项目(181231KYSB20200040);中国科学院战略性先导科技专项(A类)资助(XDA25020314)。

摘　　要：针对传统熔石英激光窗口在碱金属蒸气环境下易腐蚀的痛点问题,提出了在蓝宝石材料上制备增透微结构的方法,以实现耐高温、耐腐蚀的高透激光窗口。在理论仿真的基础上,采用干涉曝光与反应离子束刻蚀技术,在蓝宝石基底表面上制备了增透微结构,其对795 nm光的单面透过率达到99.23%。在此基础上,制备了双面增透微结构和一面增透微结构一面增透膜的蓝宝石窗口片,相较于蓝宝石基底,它们对795 nm光的透过率分别提升了12.13%和13.02%。高功率激光作用温升测试结果表明,当激光功率从35 W增加到99.6 W时,裸基板温度增加了5.9℃,但是双面增透样品的温升均为3.8℃,表明双面增透处理可以适当降低温升。同时,光束质量测试结果表明,当高功率激光作用下微结构窗口的温度控制在200℃以内时,双面增透样品的光束质量因子在横向上的变化小于0.05,在纵向上的变化小于0.06,表明该增透窗口对入射光光束质量的影响甚小。Objective Diode-pumped alkali lasers are a new type of gas lasers that utilize the high energy levels of alkali metal atoms to achieve particle number inversion.However,conventional fused-silica laser windows are easily subjected to corrosion in the alkali metal vapor environment.Therefore,in this study,we select sapphire as a window material,considering its high hardness and thermal conductivity,low expansion coefficient,and high temperature and erosion resistance.Owing to its large refractive index,the sapphire surface presents relevant anti-reflection properties,including high air and interface reflectivity.Anti-reflection surfaces are usually obtained by preparing optical films or microstructures.Anti-reflection films often require coating materials with specific refractive indices that are difficult to source.Moreover,they are susceptible to gaseous corrosion.However,their fabrication technology is relatively mature.Conversely,the production of anti-reflection microstructures requires complex processing.However,using the same substrate material to build the microstructure results in high chemical stability,mechanical properties,and resistance to laser damage.In this study,we implement a diode-pumped alkali metal laser with a 795 nm center wavelength and a working environment temperature of 200℃ by combining two different anti-reflection technologies to obtain a double-sided anti-reflection sapphire window.This is characterized by a microstructure on the side of the vapor chamber and a coating film on the side exposed to air,which enhances the temperature and corrosion resistance of the resulting laser window.Methods Based on vector diffraction theory,the effects of depth,bottom angle,period,and duty cycle on the transmittance of a one-dimensional trapezoidal structure are analyzed using COMSOL software to obtain the process tolerance of the microstructure.We use laser interference exposure to prepare a photoresist mask on a sapphire surface,and then we transfer it using reactive ion beam etching to form mi

关 键 词：薄膜 增透微结构 干涉曝光 反应离子束刻蚀 

分 类 号：O485[理学—固体物理] TN305[理学—物理]