Abstract Based on Fresnel–Kirchhoff diffraction theory, the effect of high order nonlinearities and saturable Kerr media in Z-scan experiments are theoretically investigated. Analytical expressions were obtained for the Z-scan curve, which can be strongly affected by the pump intensity. Moreover, empirical relationships were found to describe the intensity dependence of the peak-valley distance and the transmittance difference, allowing an accurate determination of parameters such as high-order nonlinearities, the saturation intensity and the confocal parameter.

中文翻译：

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Z-scan中高阶可饱和Kerr介质非线性的理论研究

摘要 基于Fresnel-Kirchhoff 衍射理论，从理论上研究了高阶非线性和可饱和Kerr 介质在Z 扫描实验中的影响。获得了 Z 扫描曲线的解析表达式，该曲线受泵强度的影响很大。此外，还发现了经验关系来描述峰谷距离和透射率差异的强度依赖性，从而可以准确确定诸如高阶非线性、饱和强度和共焦参数等参数。