摘要
本文针对不同入射角度设计了系列反射率大于99.5%的薄膜结构,理论分析了设计入射角度对没有节瘤缺陷的理想反射薄膜和有节瘤缺陷的反射薄膜电场分布的影响。采用电子束蒸发在没有预植和预植节瘤缺陷种子的基底上制备了4种不同设计入射角度的反射薄膜,对其纳秒和皮秒激光损伤特性进行了研究。结果表明,反射薄膜内部电场分布与设计入射角度和节瘤种子直径密切相关。随着设计入射角度增加,膜层厚度呈现减小的趋势,理想反射薄膜的内部电场强度降低,设计入射角度下的皮秒激光损伤阈值提升。节瘤缺陷引起膜层内部局部电场增强,导致激光损伤阈值降低。在纳秒激光辐照下,节瘤缺陷引起的初始损伤位于靠近空气的SiO_(2)层中的电场强区;在皮秒激光辐照下,节瘤缺陷引起的初始损伤位于与入射光束方向相对一侧的节瘤边界中部的电场强区。本文研究为不同入射角度的激光反射薄膜和激光系统的光路设计提供了参考。
Objective As a critical optical component in laser systems,the performance of high-reflective coatings directly influences the output power of the entire laser system.Particularly in high-power laser applications,the laser-induced damage threshold(LIDT)of these coatings is a key limiting factor.The angle of laser incidence significantly affects the LIDT of coatings.Numerous studies have explored the influence of laser incident angle on temperature distribution,electric field(E-field)distribution,and LIDT of high-reflective coatings.However,most samples are designed for specific incident angles.To enhance performance,it is essential to design coating structures based on practical usage angles.Through systematic theoretical analysis and experimental research,understanding the relationship between high-reflective coatings designed for different angles and their LIDTs can provide valuable insights for designing these coatings and selecting optimal incident angles in laser system configurations.Methods High-reflective coatings(Rs≥99.5%at the center wavelength of 1064 nm)are designed and deposited using electron beam evaporation on substrates,both with and without pre-planted nodule seeds,for different incident angles.The finite element method(FEM)is employed to simulate the E-field distributions of the coatings under their respective design angles and working laser wavelengths,as well as the localized E-field distribution optimized by nodule defects of varying diameters.The nanosecond and picosecond LIDTs of the samples are measured in accordance with ISO 21254 standards.The transmittance spectrum of the coatings is measured using a spectrometer(Lambda 1050 UV/VIS/NIR,Perkin-Elmer),and the reflectance spectrum is calculated while neglecting absorption.The surface figure of the coatings is characterized using an optical interferometer(ZYGO MarkⅢ-GPI).The root-mean-square(RMS)roughness of the coatings is measured with an atomic force microscope(AFM,Veeco Dimension-3100).Results and Discussions FEM simulation results
作者
赵洋
刘天宝
姜有恩
肖奇
周丽
邵建达
朱美萍
Zhao Yang;Liu Tianbao;Jiang You’en;Xiao Qi;Zhou Li;Shao Jianda;Zhu Meiping(Laboratory of Thin Film Optics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;College of Materials Science and Opto-Electronic Technology,University of Chinese Academy of Sciences,Beijing 100049,China;Joint Laboratory of High Power Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2024年第19期332-342,共11页
Acta Optica Sinica
基金
上海市优秀学术带头人计划项目(23XD1424100)
上海市东方英才计划领军项目
中国科学院稳定支持基础研究领域青年团队项目(YSBR-081)
国家自然科学基金面上项目(61975215)。
关键词
反射薄膜
入射角度
节瘤缺陷
激光损伤阈值
high-reflective coating
incident angle
nodule defect
laser-induced damage threshold
