多波段激光合束镜温度适应性分析

环境温度是激光合束镜设计过程中需要考虑的重要因素。研究了实际应用中环境温度对合束激光光束质量产生的影响。对高功率红外激光常用的材料Zn Se建立光-机-热集成仿真,利用瞬态导热方程和应力应变平衡方程对温度场,应力场进行仿真计算。将离散的有限元数据提取后通过Zernike多项式拟合镜面畸变。并将透镜折射率的变化转变为光程差的变化,求得出射激光远场光强分布、β因子、环围能量比BQ作为激光光束质量的评价标准。在环境温度(-40℃~+50℃)条件下,长波段激光光束质量保持较好,其β因子最大值为1.761;短波段激光光束质量接近衍射极限,其β因子最大值为1.072。结果显示在环境热冲击下通过合束镜的长波激光以及短波激光保持了良好的光束质量,满足合束镜环境温度使用要求。

Temperature Adaptability Analysis on Multi-band Laser Combination Mirror

Environment temperature is an important factor for beam combination mirror designing. In this paper,the in-fluence of laser quality in different temperature is researched. Thermal/structural/optical integrated analysis model of ZnSe material is established, it is commonly used in infrared high power laser system.The temperature field and stress field using transient heat conduction equation and stress-strain equilibrium equation are stimulated. The discrete finite el-ement data and fitting surface deformation are extracted by Zernike polynomial. The change of refractive index is trans-formed into the optical path difference. The beam quality is evaluated by the being obtained far-field intensity of output laser and β factor and being encircled energy BQ. Under the condition of environment temperature (-40℃~+50℃), a good beam quality is kept in the long wavelength,the max β equals to 1.761;The short-wavelength laser beam quali-ty approach diffraction limit, the max β equals to 1.072. The result shows that a good beam quality is kept in the short wave and long wave laser under environment thermal impact,the requirements of environment temperature are met.