高功率超短激光脉冲信噪比的研究

 针对高功率激光系统中信噪比低的问题，基于描述超短脉冲传输的非线性薛定谔方程进行数值模拟，研究了高阶群速度色散、光谱调制及自相位调制对脉冲信噪比的影响；新建立了用于分析光栅平整度对脉冲信噪比的影响的物理模型并进行了相应的模拟，分析了光栅的质量要求或补偿精度。研究表明：对于100 fs的高斯脉冲，要保证信噪比达到10⁸，应将三阶色散量限制在4.8×10⁵ fs³以下，B积分的值应小于0.2，光谱的调制幅度应小于10^-4，光栅平整度应优于λ/100。

Signal-to-noise ratio of ultrashort high-power pulse

Based on the nonlinear Schrdinger equation, a simulation was carried out to solve the problem of the signal-to-noise ratio being low. The research dealt with the influence of higher-order dispersion, spectral modulation and self-phase-modulation on the signal to noise ratio. Furthermore, a physical model was built to analyze the impact of the flatness of gratings. The results show that for a 100 fs input Gaussian pulse, in order to make the signal-to-noise ratio bigger than 108, the third-order-dispersion should be kept below 4.8×105 fs3, the B-integral below 0.2, the amplitude of the modulation of spectrum below 10-4 and the flatness of gratings smaller than λ/100 .