湍流大气中随机相位光束阵列的斜程传输特性

Propagation of Beam Array with Random Phase through Atmospheric Turbulence in a Slant Path

基于广义惠更斯-菲涅耳原理,理论上研究了具有随机相位的激光束阵列在湍流大气中的斜程传输特性。主要研究了湍流强度、占空比、传输高度和光束间的相位差对光束阵列平均光强的影响。研究结果表明:湍流会使合成光强减弱,光束扩展;同时,占空比越小,合成光场的峰值光强越小,即合成效果越差;随着光束间相位差的增大,主峰强度快速下降,最终合成光束近似于单束高斯光束模型。与水平传输时的结果进行了比较,结果显示大气湍流对斜程传输光束扩展的影响明显小于水平传输的情况。计算模型和结果为工程实际中合成方案的选择和评估提供了参考。

Based on the extended Huygens-Fresnel principle, the properties of a beam array with random phase distributions propagation through a turbulence atmosphere in a slant path are analytically investigated. Influences of turbulence intensity, duty ratio, transmission height and the phase difference between the beams on the average intensity of the beam array are researched. The results show that turbulence can cause the decrease of the peak and the spreading of beam; at the same time, the smaller the duty ratio, the smaller peak intensity, the combination effect is even worse; with the random phase difference between the beams increasing, the main peak intensity decreases fast and the far-field coherent combining irradiance distribution gradually evolves into the pattern of the single Gauss beam distribution model. The results for a slant path are compared with those for a horizontal path, and as a result, the influence of the atmospheric turbulence to the beam spreading along the slant path is much smaIler than that along the horizontal path. The mathematical model and calculation result can offer a reference for choosing and evaluating different combining schemes.