The crucial role of nonlinear propagation effects in the self-guiding of femtosecond laser pulses required accurate representation of nonlinearities to describe them. In this paper, an improved theoretical model has been proposed to study the height distribution of the atmospheric nonlinear refractive index. The results show that the revised model obviously improves accurate estimation of nonlinear index at the long wavelength band. Based on the model, we also found the atmospheric nonlinear refractive index differs much from the lower atmosphere to the upper atmosphere. Our results are essential for engineering applications based on the long-distance ultrashort laser pulses’ transmission in diverse atmosphere.

中文翻译：

---

基于理论计算模型的大气非线性折射率高度分布研究

非线性传播效应在飞秒激光脉冲的自引导中的关键作用需要准确表示非线性来描述它们。本文提出了一种改进的理论模型来研究大气非线性折射率的高度分布。结果表明，修正后的模型明显提高了长波段非线性指数的准确估计。基于该模型，我们还发现大气非线性折射率从低层大气到高层大气存在很大差异。我们的结果对于基于长距离超短激光脉冲在不同大气中传输的工程应用至关重要。