宽光束进入展宽器提高输出脉冲对比度分析

Analysis of Improved Contrast from a Chirped Pulse Amplification Laser System by Increasing the Beam Size in the Stretcher

根据分析啁啾脉冲对比度模型,通过光线追迹法详细分析了展宽器对输出脉冲对比度的影响.发现当扩大进入展宽器的入射光束口径,从2mm扩大到40mm时,输出脉冲的对比度提高了近两个数量级;同时发现在相同条件下,当输入脉冲为双曲正割函数时,其输出脉冲的对比度明显好于输入脉冲为高斯脉冲和矩形脉冲的情形·

The impact of the stretcher on the contrast ratio of the out pulse is analyzed making use of the ray- tracing method, which is based on the contrast ratio model of chirped pulse. When the beam size in the stretcher is increased from 2 mm to 40 mm,the contrast of the output pulse approximately increase two magnitude. When the input pulse is Sech^2 ,the contrast of the output pulse is better than what the input pulse is Gassian or Rectangular.