Propagation properties of partially coherent quasi-rectangular beams in a turbulent atmosphere
Propagation properties of partially coherent quasi-rectangular beams in a turbulent atmosphere
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DOI：
10.1364/osac.414038
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发表时间：
2021-04
期刊：
影响因子：
1.6
通讯作者：
Zhengxian Zhou;Chang-An Xu;Hua-Feng Xu;Yangsheng Yuan;J. Qu
中科院分区：
文献类型：
--
作者：
Zhengxian Zhou;Chang-An Xu;Hua-Feng Xu;Yangsheng Yuan;J. Qu
从理论上介绍了一类具有均匀关联的随机、广义稳定光束--部分相干准矩形光束。基于扩展惠更斯-菲涅耳原理，推导了光束在非科尔莫戈洛夫湍流中的交叉谱密度(CSD)、有效曲率半径和光束漂移的解析表达式。结果表明，与自由空间相比，部分相干准矩形光束的最大光强位置在中距离发生了较远的移位，湍流中的移位受到抑制。随着相干长度的增加，有效曲率半径从无穷大减小到一个常数，在其他参数固定的情况下，有效曲率半径总是比自由空间传输中的曲率半径大。此外，可以通过选择相对较小的初始光束宽度、较短的相干长度或较长的波长来减小光束漂移。这些结果对于通过远距离湍流通道工作的光学系统是重要的，在这种通道中，光束必须具有与距离相关的倾斜，例如在绕过轴线上的障碍物时。
A class of random, wide-sense stationary optical beams with uniform correlations, named the partially coherent quasi-rectangular beam, is introduced theoretically. Based on the extended Huygens-Fresnel principle, the analytical expressions for the cross-spectral density (CSD), effective radius of curvature, and beam wander of the beam in the non-Kolmogorov turbulence are derived. It is found that the position of maximum intensity of the partially coherent quasi-rectangular beams shifts farther from the axis at intermediate distance, the shift in the turbulence is depressed compared to that in free space. As the effective radius of curvature decreases from infinity to a constant with the increase of the coherence length, it always takes a higher value than that in free-space propagation when the other parameters are fixed. In addition, the beam wander can be reduced by picking a relative small initial beam width, short coherence length, or long wavelength. These results are of importance for optical systems operating through long-range turbulent channels in which a beam must have a range-dependent tilt, e.g. on travelling around an obstacle on the axis.