椭圆高斯光束在强非局域非线性介质中的传输特性

研究了傍轴椭圆高斯光束在强非局域非线性介质中的传输特性，得到了其各参量的演化方程 及其精确解析解.通过对束宽演化方程及其精确解析解的进一步分析，发现傍轴椭圆高斯光 束在强非局域非线性介质中传输时，两横向方向束宽作周期性变化.不管初始功率为多大， 光束都将周期性的由椭圆高斯光束演化为圆对称高斯光束，再由圆对称高斯光束演化为椭圆 高斯光束；并且在演化的过程中，椭圆的半长轴和半短轴会作周期性交替变化.另外，在一 定初始功率下，傍轴椭圆高斯光束可以保持某一横向方向的束宽不变，得到光孤子. 关键词： 强非局域非线性介质 非局域非线性薛定谔方程 椭圆高斯光束 参量演化方程 空间孤子

The propagation properties of the elliptic Gaussian beam in strongly nonlocal nonlinear media

In this paper,the propagation properties of a paraxial elliptic Gaussian beam in strongly nonlocal nonlinear media are discussed.We obtain a set of evolution equations for the param eters of the elliptic Gaussian beam,and also their exact analytical solutions.When the beam propagates in the media,the beam widths in the two trasverse directions oscillate generally along a propagation direction.What ever an intial power is,the elliptic Gaussian beam will evolve into the circular ly symmetrical Gaussian beam,then evolve back to the elliptic Gaussian beam agai n,but with the change of its major axis into the minor axis.This process is peri odic.For a certern initial power,the beam width in one trasverse direction can k eep constant,which is an optical soliton state,while the width in the other tran sverse direction vibrates.