非Kolmogorov大气湍流对高斯阵列光束光强闪烁的影响

Influence of non-Kolmogorov atmospheric turbulence on scintillation of Gaussian array beams

基于广义惠更斯-菲涅尔原理,采用Rytov方法推导了径向分布高斯阵列光束在非Kolmogorov湍流大气中传输时的光强闪烁指数表达式,分析了径向半径r0、光束个数N、广义指数α及传输距离L对轴上和离轴闪烁指数的影响。结果表明:轴上和离轴闪烁指数随着α的增加均先增大后减小,值得注意的是不同的r0光束的闪烁指数达到极大值所对应的α略有不同,轴上闪烁指数随着r0的增大达到极大值所对应的α呈减小趋势,而离轴闪烁指数随着r0的增大达到极大值所对应的α呈增大趋势;光轴附近各阵列光束的闪烁指数小于高斯光束的闪烁指数,随着px的增大阵列光束闪烁指数将大于高斯光束闪烁指数。当r0相同时N越大闪烁指数越小,当N相同时闪烁指数随r0的增大非单调变化,而是存在一个极小值。

The expression for the scintillation index of radial Gaussian array beams propagation in non-Kolmogorov turbulence was derived by using the extended Huygens-Fresnel principle and Rytov method.The influences of the ring radius r0, beam number N, general exponent α and propagation distance L on the on-axis and off-axis scintillation index were studied. The results show that both the on-axis and offaxis scintillation index rise initially as α becomes larger, but later the scintillation reduce as α grows further. It is worth noting that beams with different r0 reach its maximum scintillation correspond to different α. The scintillation index values of array beams are smaller than that of a Gaussian beam around the on-axis point, but with the increase of the transverse coordinate pxthe scintillation index values become larger than that of a Gaussian beam. Scintillation index decreases with the increase of N,but the dependence of scintillation on r0 is not monotonic.