用于高能激光的快速控制反射镜设计方法研究

Research on Design Methods of FSM Used for High Energy Laser

为降低高功率激光辐照下快反镜吸收激光能量产生的影响,对用于高能激光的快反镜设计方法进行了研究。首先从降低反射镜与基体结构对激光的吸收角度提出了镜片两面均镀高反射膜的方案,通过试验测试了该镀膜方案下镜片与基体在高功率激光持续辐照下的温升,并分析了该温升下粘接剂的粘接强度。最后设计了一种新式柔性铰链结构可减少托架与镜片的热应力耦合,并通过有限元分析对其进行优化,确定最优参数。试验与分析结果表明,高能激光照射试验下镜片最高温升为75℃且粘接剂拉伸强度足够;背部基体结构温升小于5℃,驱动器与传感器几乎无温升;镜片温度升高30℃后,新式托架结构使镜片面形RMS值从1/10λ提高到1/25λ（λ=632.8 nm）。试验与仿真分析结果均表明镀膜方案与新式铰链设计合理可行。

Fast steering mirror absorbs laser energy when irradiated by high-power laser. Research on design methods of FSM for high energy laser is studied in order to lighten this circumstance. First,scheme for coating high reflective film on both sides of mirror is proposed from the point of reducing the absorption of laser by the reflecting mirror and structure. Temperature rise of mirror and substrate under continuous radiation of high energy laser is tested.Then bonding strength after temperature rising is analyzed. Finally a new type of flexible hinge is designed and optimized by finite element analysis to reduce thermal stress coupling of mirror and bracket,then the optimal parameters are determined. Test and analysis results show that in experiment the highest temperature rise of mirror is 75℃ and adhesives remain enough bonding strength,and temperature rise of base structure is less than 5 ℃. The actuator and sensor are hardly affected by laser. RMS of reflecting mirror figure is improved from 1/10λ to 1/25λ（ λ = 632.8 nm） with new flexible hinge structure when the mirror temperature increases by 30 ℃. Experiment and simulation results show that the coating scheme and design of flexible hinge are rational and feasible.