高功率激光装置中鬼像的模拟-应用实际光线追迹法

Mitigating Damage of the Ghost in High Power Laser Facilities by Real-Ray Trace

高功率固体激光装置中正常光束的残余反射将形成能量较大的鬼点,它们极易对元器件造成损害,因此对一阶及多阶鬼点的位置作定量分析对高功率激光系统设计是非常必要的。采用将近轴分析与实际光线追迹相结合的分析方法,对神光Ⅲ原型装置进行了一套完整的杂散光分析。首先在近轴条件下对系统中可能产生的一阶至多阶鬼点进行了全面的计算和定位,列出其来源和鬼点较集中的区域,如普克尔盒一个窗口的前表面附近鬼点能量比较集中,然后通过大量的实际光线追迹对这些元件进行重点考察,模拟其表面的能量分布,为如何减小鬼点数目,从而避免鬼点能量造成的损伤提供了详尽的数据参考。

Ghost reflections are a major consideration in the optical design of the high-power laser facilities. A thorough ghost analysis has been carried out for the technical integration line (TIL), which is the full scale prototype for Shenguang-III laser facility (SG-III), with a method of combination of paraxial ray tracing and real ray tracing. This paper takes one of the dangerous surfaces as example, which is the front plane of a window in Pockels cell, simulating the energy distribution graph on it by numerous real-ray tracings. According to the shape of ghost energy graph and its corresponding optical structure, suggestions are made to effectively mitigate the damage on the studied optical surfaces.