时域与空域结合实现光束匀滑的光谱优化分析

为改善焦斑的均匀性以应用于惯性约束聚变(ICF)的实验,从焦斑形态的控制出发,在随机相位板(RPP)和连续相位板(CPP)做空域整形下,用同样带宽和最大谱色散角,模拟了不同光谱形状的匀滑效果,通过焦斑强度的功率谱密度(PSD)和平顶的均方根(RMS)对获得的焦斑进行评价.结果表明,改善光谱形状可以提高匀滑效率,优化光谱相对主流的正弦调频光谱对匀滑效果的均方根值可提高43.7%.同时,设计相位板时考虑焦斑上不同空间频率的权重,有利于匀滑.

Analysis of Laser Optimized Spectrum for Smoothing the Focused Spot by Temporal and Special Method

For improving the uniformity of the focal spot in the inertial confinement fusion(ICF) experiments,we simulated the effects of the different spectral shapes of broadband light with the focused spot through phase plate,such as random phase plate(RPP) or continuous phase plate(CPP), and the uniform bandwidth and maximal dispersive angle.The power spectral density(PSD) and root mean square(RMS) of the focused spot intensity were used to evaluate smoothing effect.The results show that the optimized spectrum can improve smoothing efficiently,and the RMS can be improved by 43.7% compared with the sinusoidal phase modulated spectrum.Generally,the smoothing efficiency would be better if the weighting of the different spatial frequencies of the focused spot was considered to design phase plate.