小尺度自聚焦理论的非傍轴修正

A Non-paraxial Correction to the Small-scale Self-focusing Theory

从原始的非傍轴传输方程出发 ,研究了光束的非傍轴效应对小尺度自聚焦现象的影响 结果是 ,非傍轴效应对不稳定区间的截止频率没有影响 ,但使最快增长频率增大 ,最大增长率减小 同时 ,由于非傍轴的影响出现了一个新的增益区间 ,在该区间里 ,增益远远大于在原区间里的增益 ,但是 ,随着背景光强的增大 。

On the basis of the linear stability theory, the non paraxial nonlinear Schrdinger equation is used to study the small scale self focusing of intense laser beams. With a comparison of the gain spectrum obtained with paraxial and non paraxial equations, it shows that non paraxiality makes no influence on the cutoff frequency, but increases the fastest growing frequency and reduces the maximum gain of the perturbation. And a new region where the small scale self focusing occurs is found due to the non paraxiality. Some discussions are given on this new region around the small scale self focusing.