基于Rugate薄膜的高功率激光非聚焦型空间低通滤波技术研究

项目名称： 基于Rugate薄膜的高功率激光非聚焦型空间低通滤波技术研究

项目编号： No.61205002

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 信息四处

项目作者： 郑光威

作者单位： 中国人民解放军空军工程大学

项目金额： 26万元

中文摘要： 针对传统聚焦型针孔滤波技术在改善高功率激光光束质量方面的缺陷，本项目深入探索Rugate薄膜应用于高功率激光非聚焦型空间低通滤波的可行性。采用时域有限差分理论，分析Rugate薄膜的角谱响应与光谱响应的相互关系，并基于其光谱响应特性与其折射率分布的关系表达式，得出其角谱响应特性随其折射率分布的变化规律，以指导符合特定空间低通滤波需求的薄膜的结构设计。重点解决具有窄角谱选择性，且宽光谱选择性Rugate薄膜设计问题，为脉冲或短脉冲激光空间低通滤波提供理论依据，并分别针对连续、脉冲和超短脉冲激光设计空间低通滤波装置。采用严格耦合波理论和空频域功率谱密度等指标，对其空间低通滤波特性进行评价。利用温度场设计理论，分析在同种镀膜材料的前提下，Rugate薄膜较多层介质薄膜具有更高抗光损伤能力的机理。实验验证采用斜向沉积法所制作薄膜的空间低通滤波效果，并和针孔滤波进行对比，分析其取代针孔滤波的可行性。

中文关键词： 空间低通滤波；Rugate薄膜；角谱选择性；薄膜设计；透射角谱函数

英文摘要： The traditional focusing pin-hole spatial filter has lots of disadvantages to improve the beam quality of high power laser beam. So the project analyzes the validity of Rugate coating for non-focusing low-pass spatial filtering of high-power laser beam profoundly. Based on finite-difference time-domain method, the relationship between the angular spectrum response characteristics and the light spectrum response characteristics is investigated. And by the equation of the light spectrum response characteristics with the coating's refractive index, the angular spectrum response characteristics with the change of the refractive index are formulated. And the formulation can be used to conduct the design of Rugate coating for different filtering requirements. The Rugate coating which has narrow angular spectrum bandwidth and wide light spectrum bandwidth simultaneously is designed. So it is proved theoretically that Rugate coating can be used for the spatial filtering of short and ultra short laser pulse. And the configurations for the spatial filtering of short and ultra short laser pulse are fabricated, respectively. Using rigorous coupled wave theory and power spectrum density in spatial spectrum domain, the characteristics of Rugate coating for spatial filtering are evaluated. Based on temperature field distributi

英文关键词： low-pass spatial filter；Rugate coating；angular spectrum selectivity；coating synthesis；transmitting angular spectrum function