中文摘要：

采用高斯分解法（GD）对大非线性相移下的Z扫描特性进行了分析，通过对数值算法的优化，将GD推广到对脉冲入射激光下大非线性相移下的Z扫描理论分析．对不同条件下大非线性相移Z扫描曲线峰谷结构的比较，发现在大非线性相移的情况下，Z扫描曲线的峰和谷随透过光阑或入射光强变化表现出某些新的特性．随着透过光阑孔径的增加，Z扫描曲线峰的变化要明显快于谷的变化，而且在谷明显存在的情况下，峰很快消失．采用皮秒脉冲激光下的纯二硫化碳实验对理论结果加以验证，实验结果和理论分析相一致．我们的分析结果对大非线性相移下Z扫描测量有一定的指导性意义，避免在大非线性相移下对Z扫描结果产生错误的分析．

英文摘要：

Using Gaussian decomposition （GD） method, we studied the theory of Z-scan with large nonlinear phase shift induced by a pulsed laser. It has been verified that the GD method is still valid to deal with analysis of Z-scan measurements with large nonlinear phase shift. By comparing the peak-valley configuration of the Z-scan curves for large nonlinear phase shift induced by pulsed and CW laser, we found that some new peak-valley features of the Z-scan curves appear as the aperture size or light intensity increases in the case of large nonlinear phase shift. Meanwhile, we carried out the Z-scan experiments of pure CS2 to confirm the results of numerical simulation in the case of large nonlinear phase shift induced by a picosecond pulsed laser. The experimental results agree well with the theoretical. Our results have some significance to the measurement of Z-scan with large nonlinear phase shift induced by a pulsed laser.