This paper considers the calculation of the nonlinear losses induced in a circular aperture enlighten by a focused Gaussian beam (GB) subject to optical Kerr effect. Such a problem known since a long time typically requires the numerical calculation of a diffraction integral which becomes rapidly cumbersome in the case of repetitive applications. Alternatively, we propose a new simple modelling completely analytical. This method called as Non Gaussian Gaussian Beam modelling is based on the beam propagation factor \(M^{2} > 1\) of the GB traversing the Kerr aberration. The \(M^{2}\) is found to depend only on the nonlinear Kerr phase shift and independent of the wavelength and the width of the GB incident on the Kerr medium. This simple modelling has been applied to three applications: Kerr Lens Mode locking (KLM) mechanism, optical limitation, and Z-scan technique for a large nonlinearity.

本文考虑了在受光学克尔效应影响的聚焦高斯光束 (GB) 启发下的圆形孔径中引起的非线性损耗的计算。这种长期以来已知的问题通常需要对衍射积分进行数值计算，这在重复应用的情况下会很快变得麻烦。或者，我们提出了一个新的简单建模完全解析。这种称为非高斯高斯光束建模的方法基于穿越克尔像差的 GB的光束传播因子\(M^{2} > 1\)。的\（M ^ {2} \）发现仅取决于非线性克尔相移，而与入射在克尔介质上的 GB 的波长和宽度无关。这种简单的建模已应用于三个应用：克尔透镜锁模 (KLM) 机制、光学限制和用于大非线性的 Z 扫描技术。