高功率激光装置中终端光学系统的鬼像分析

Ghost analysis of the terminal optical system in high power laser set

基于光传输的多叉树原理,研究了用于惯性约束聚变的高功率激光装置终端光学系统中多级衍射和多次反射杂散光与鬼点分布,根据光线经色分离光栅的传播规律进行了实际鬼光路计算,对聚焦透镜、色分离光栅、防护片组成的光学系统产生的杂散光及会聚鬼点进行了全面分析,得出三次谐波鬼点620个,二次谐波和基频光的会聚鬼点相对较少。分析表明非球面的一次反射鬼点最具威胁,大角度衍射和倾斜平面反射使大量鬼点向系统外部移动,并增大鬼光束的像差,减小其危害。这种方法可以以动态数据结构捕捉全部鬼点,并获得鬼光束结构。

Based on the multiple fork tree of light transmission, the stray light and ghosts caused by multi-order diffraction and in inertia confined fusion multi-reflection in the terminal optical system of high power laser setup used （ICF） were discussed. Real ghost rays were traced according to the ray transmission law through a color separation grating. And over-round analysis for the stray light and the focusing ghost images in the system, which consists of a focusing lens, a color separation grating, and baffle shields, was completed.It was observed that there were 620 third harmonic ghosts and relative less second harmonic and fundamental frequency ghosts. It can be concluded that the ghost formed by the first reflection of aspheric surface is most harmful. With the diffraction of large angles and the reflection of tilt planes, a lot of ghosts are moved outside the system and their aberrations are increased so that their harmfulness is weakened. All of the ghosts can be caught in the form of dynamic data structure and the ghost beam structure can be obtained.