部分相干光在大气湍流中斜程传输路径上的展宽与漂移

Spreading and Wander of Partially Coherent Beam through Atmospheric Turbulence in a Slanted Path

基于Andrews和Philips经典漂移方差模型,利用部分相干高斯-谢尔光束在大气湍流中斜程传输的光束扩展半径,推导出考虑外尺度情况时部分相干高斯-谢尔光束斜程情况下的漂移方差表达式,应用随高度变化的大气结构常量模型进行数值计算,对比分析了部分相干光和完全相干光在大气湍流中的展宽和漂移特性.结果表明:相同的传输条件下,部分相干光比完全相干光的光束扩展更迅速,受湍流的影响也更小;初始半径越大,接收机高度越高,光束的扩展效应越小;随着传输距离的增大,光束的质心漂移方差随光束初始半径的增大而减小,不同相干性的光束漂移方差变化很小;完全相干光的光束漂移受波长的影响较小,而部分相干光的波长越长,漂移越明显.

Based on the the general expression of the beam wander variance modeled by Andrews and Philips, the expression of wander variance for partially coherent Gaussian-Schell model beam considering the outer scale was derived using beam width formula of partially coherent Gaussian-Schell model beam propagating in slanted atmospheric turbulence, combining the turbulence structure constant model varying with height, numerical calculations were conducted and the spreading and wander variance of partially coherent beam and fully coherent beam were comparatively analyzed. The results show that, compared to the fully coherent beam, the partially coherent beam spreads faster and is less affected by turbulence under the same propagation conditions, and the beam spreading effect becomes weaker as the initial beam radius becomes larger or the height of the receiver becomes higher. As the propagation distance increases, the beam wander variance decreases with the increase of initial beam radius, the beam wander variance caused by different coherence have little difference. The wander of fully coherent beam is less affected by the wavelength, while the longer the wavelength of the partially coherent beam, the more obviously the beam wanders.