(O)ffner展宽器曲面镜误差对输出脉冲对比度的影响

在(O)ffner展宽器的设计研究中,对曲面镜曲率半径的误差研究非常重要,它直接影响输出脉冲的质量.因此有必要分析(O)ffner展宽器中曲面镜曲率半径的误差对输出脉冲对比度的影响.参考(O)ffner展宽器的光线追迹模型,建立了(O)ffner展宽器中曲面镜曲率半径存在误差时的光线追迹模型;根据建立的模型.详细分析了曲面镜曲率半径的误差对输出脉冲质量的影响;发现在目前曲面镜曲率半径的加上误差在0.2%～0.5%的情况下,完全可以满足神光Ⅱ拍瓦激光装置中对展宽器的要求;同时发现如果曲面镜曲率半径存在误差时,应该尽量使两曲面镜之间的距离保持为凹面反射镜曲率半径的一半,而不是使两曲面镜保持同心.

Influence of Mirror Curvature Radius Manufacture Errors in (O)ffner Stretcher on Output Pulse Contrast

In the design of the Offner stretcher, it is very important to investigate the mirror curvature radius errors, which has a direct impact on the quality of the output pulse. So it is necessary to analyse the effect on the output pulse contrast due to the mirror curvature radius manufacture errors in the ffner stretcher. A ray-tracing model for ffner stretcher with these errors is established. Based on the model, effects on output pulse contrast through the stretcher is analyzed.When the mirror curvature radius error is between 0.2%～0.5%, it can fully meet the requirements for the SHENGUANG Ⅱ petawatt laser facility. Also, when there is error for the mirror curvature radius, keeping the distance between concave mirror and convex mirror half of curvature radius of the concave mirror is better than keeping the two curve mirrors in the same center.