随机电磁光束通过大气湍流的传输特性

Properties of Stochastic Electromagnetic Beams Propagating Through Atmospheric Turbulence

建立了随机电磁光束通过大气湍流的传输模型,并对比研究了高斯-谢尔模光束在大气湍流和自由空间的传输特性。研究表明,光谱偏振度随传输距离变化,并在远场趋于稳定;得到了远场稳定偏振度的解析表达式,其在大气湍流传输中与光束的自相关长度和互相关长度无关;光谱相干度在自由空间的远场趋于1,而在大气湍流的远场趋于0,并且湍流强度越大光谱相干度下降越快,光谱密度衰减越快。

The propagation model of stochastic electromagnetic beams through atmospheric turbulence was constructed. And a comparison between the properties of Gaussian Schell-model beams through atmospheric turbulence and free space was studied. It was shown that the spectral degree of polarization was variable with distance, and tend to stable value after a long-propagation distance. The analytic expressions for the stable spectral degree of polarization at far field were obtained, which were unrelated to self-correlation length and multi-correlation length of beams in atmospheric turbulence. The spectral degree of coherence at far field tends to 1 in free face, whereas it tends to 0 in atmospheric turbulence. The stronger the turbulence was, the faster the spectral degree of coherence decreased, and the faster the spectral density reduced.