部分相干Airy涡旋光束在非Kolmogorov谱中的模态强度

Modal intensity of partially coherent Airy vortex beams in non-Kolmogorov turbulence

为了探究部分相干Airy涡旋光束在非Kolmogorov谱中模态强度的演化规律,基于广义的Huygens-Fresnel原理和Rytov近似理论,推导了部分相干Airy涡旋光束的轨道角动量模态概率的解析式。结合MATLAB的数值模拟,研究了部分相干Airy涡旋光束在非Kolmogorov谱湍流大气中传输时湍流参量和波束参量与涡旋模态强度的关系,对部分相干Airy涡旋光束的相干宽度在传输过程中对模态强度的影响进行了理论分析。结果表明,选取拓扑荷数较小、主亮环半径较大、波长较长的部分相干Airy涡旋光束能有效减缓湍流效应的影响,减小强湍流中模态间的串扰;较大的湍流谱幂指数和较小的探测器孔径直径能提高部分相干Airy涡旋光束的模态强度;与完全相干涡旋光束相比,部分相干涡旋光束具有较强的湍流阻力,在大气湍流中能有更好的传输性能,相干性较差会导致螺旋谱分布弥散。这些结果对自由空间光通信的研究具有一定的参考价值。

In order to study the modal intensity of partially coherent Airy vortex beams in the non-Kolmogorov turbulence,based on the generalized Huygens-Fresnel principle and the Rytov approximation theory,the analytical expressions of modal probability of partially coherent Airy vortex beams carrying orbital angular momentum were derived and the numerical simulation was carried out with MATLAB.The influence of turbulent parameters and beam parameters on the intensity of the vortex mode when partially coherent Airy vortex beams propagate in a non-Kolmogorov turbulence were investigated,the influence of the coherence width of partially coherent Airy vortex beams on the modal intensity during transmission was theoretically studied.The results indicate that partially coherent Airy vortex beams with a smaller topological charge,larger main ring radius and longer wavelength can effectively mitigate the influence of turbulence effect and reduce the crosstalk between modes in strong turbulence;larger non-Kolmogorov spectrum parameter and smaller detector aperture diameter can improve the modal intensity of partially coherent Airy vortex beams.Furthermore,compared with fully coherent vortex beams,partially coherent vortex beams have stronger turbulence resistance and better transmission performance in atmospheric turbulence.While poor coherence will lead to dispersion of spiral spectrum.The research results provide reference for the application of partially coherent Airy vortex beams in free space optical communication.