神光-Ⅲ原型装置用速度干涉仪的光学系统设计

Design of VISAR optical system for Shen-Guang-Ⅲ prototype

基于激光多普勒频移效应研制了一套应用于惯性约束聚变(ICF)研究的任意反射表面干涉测速系统(VISAR)。采用532nm的照明激光设计了一套光谱带宽为0.2nm的光学系统,通过合理选材,保证了光学系统的防辐射性能;基于光学膜系设计,滤除了526nm的强干扰打靶激光以及其它波段的杂散光;采用模块化方法并设计光学铰链进行模块对接,简化了系统调试的复杂程度;利用激光对干涉仪粗调,再利用白光精调,实现了零程差调试。设计的系统光路总长为6.3m,物方视场范围为φ1.0mm,放大倍率为5×、10×;静态实验显示,干涉条纹平直、调制度达到0.67以上,物方分辨率达到5.3μm。目前,该系统已成功地在神光-Ⅲ原型装置上进行了动态实验。

To establish a Velocity Interferometer System for Any Reflector（VISAR） for the shock velocity measurement based on a laser Doppler shift effect, an optical system with a bandwidth of 0. 2 nm was designed by using the 532 nm laser illumination. By choosing advisable materials, the fused silica was used in the optical system to improve the radiation resistance. Then, the second harmonics of the drive lasers and other stray lights are filtered by band-pass filters and laser line filters. To simplify the system assembly, the modularized design method and a optical gemel hinge were taken to compose models. Furthermore, the 532 nm laser was used for initially adjustment and the white light was used for accurately adjustment to implement the optical path difference to the zero. The proposed system show its total path length is 6.3 m, field of view is φ01.0 mm, and magnifications are 5× and 10× A static experiment was undertaken, which can offer straight fringes and can give a static contrast above 0.67 and a resolution of 5.3 um. Moreover, a dynamic experiment of the system was carried out on the Shen-Guang laser-Ⅲ facility successfully.