光学学报, 2020, 40 (20): 2014001, 网络出版: 2020-09-30
激光系统中元件热效应时空特性分析 下载: 846次
Analysis of Spatio-Temporal Characters of Thermal Effects of Optical Components in Laser System
激光光学 元件热效应 热相差 时空特性 自适应校正 laser optics thermal effect thermal aberration spatio-temporal characteristics adaptive optics
摘要
从热传导方程和热弹性方程出发,基于EasyLaser仿真软件,对激光辐照Si反射镜、SiO2窗口镜温度分布和热相差进行了模拟计算,比较了相同吸收的情形下,两种元件温升、热相差分布的时间、空间特性,并开展光-热-力控制多物理耦合仿真,比较了激光辐照Si反射镜、SiO2窗口镜热效应对激光传输远场特性影响和自适应光学校正效果。仿真结果表明,由于SiO2窗口镜导热性能差,热相差随激光辐照时间的增加而线性增加,其分布与辐照激光光斑空间分布相似,且在激光辐照停止后较长时间内仍然存在;而Si反射镜导热性能好,温度分布在较短时间内匀化导致温度梯度小,热相差先快速、后缓慢增加,在激光辐照停止后热效应的影响很快消退。实验光斑强度的空间分布,对两种元件热效应的影响不同:对于SiO2窗口镜,其热相差的高空间频率成分增加,严重影响激光光束远场传输与自适应光学校正效果,而Si反射镜热导率大,受到的影响较小。
Abstract
Starting from heat conduction equation and thermal elastic equation, based on EasyLaser simulation software, the temperature distribution and thermal aberration of laser irradiated Si reflective mirror and SiO2 window mirror are simulated and calculated. The spatio-temporal characteristics of temperature rise and thermal aberration of the two elements under the same absorption are compared. The optical-thermal-mechanical control multi-physical coupling simulation are carried out to compare the thermal effect of the laser-irradiated Si mirror and the SiO2 window mirror on the far-field characteristics of laser transmission and the effect of adaptive optics correction. Simulation results show that due to the poor thermal conductivity of the SiO2 window mirror, the thermal aberration linearly increases with the increase of the laser irradiation time, and its distribution is similar to the spatial distribution of the irradiated laser spot, and it still exists for a long time after the laser irradiation is stopped. The Si reflector has good thermal conductivity. The temperature distribution is homogenized in a short time, resulting in a small temperature gradient. The thermal aberration first increases rapidly and then slowly, and the influence of the thermal effect disappears quickly after the laser irradiation is stopped. The spatial distribution of the experimental spot intensity has different effects on the thermal effects of the two components: for the SiO2 window mirror, the high spatial frequency component of the thermal aberration increases, which seriously affects the far-field transmission of the laser beam and the effect of adaptive optics correction, while the Si mirror is hot. The conductivity is large, and the impact is small.
胡鹏, 张建柱. 激光系统中元件热效应时空特性分析[J]. 光学学报, 2020, 40(20): 2014001. Peng Hu, Jianzhu Zhang. Analysis of Spatio-Temporal Characters of Thermal Effects of Optical Components in Laser System[J]. Acta Optica Sinica, 2020, 40(20): 2014001.