部分相干Airy光束在大气湍流中的光强演化

Evolution of the Intensity of Partially Coherent Airy Beam in Atmospheric Turbulence

为了利用Airy光束的无衍射、自恢复和自弯曲特性抑制大气湍流效应,实现远距离无线光通信,对部分相Airy光束在大气湍流中传输时的光强演化进行了研究.利用高斯-谢尔模型的交叉谱密度函数、广义惠更斯-菲涅尔原理以及Rytov相位近似法,推导了部分相干Airy在湍流大气中平均光强的表达式.分别从传播距离、湍流强度等方面对光强分布的影响进行了模拟仿真,并对光束自身参数对光强分布的影响进行了相关实验验证.结果表明:随着传播距离的增加,部分相干Airy光束的旁瓣逐渐衰减,主瓣逐渐扩散;在传播足够远时,其旁瓣逐渐消失,主瓣逐渐演化为高斯分布.仿真和实验结果一致表明光束的截断因子越小、特征长度和相干长度越长,光束的光强分布保持越完整.

In order to inhibit the effects of atmospheric turbulence by using the non-diffracting, self recovery and self bending property of Airy beam and realize the remote wireless optical communication, the intensity evolution of partially coherent Airy beams propagating in turbulent atmosphere were studied. By using the cross spectral density function of Gauss-Schell model, the generalized Huygens-Finel principle and the methods of Rytov phase approximation, the expressions for the average intensity of partially coherent Airy in turbulent atmosphere were derived. Then, the influences of propagation distance, turbulence intensity and other parameters on the intensity distribution were simulated, and the influence of the beam parameters on the intensity distribution was verified by experiments. The results show that the side lobe of the partially coherent Airy beam is gradually attenuated and the main lobe is gradually spread, with the increase of the propagation distance. When the spread is long enough, the side lobe is gradually lost, and the main lobe is gradually evolved into Gauss distribution. The simulation and experimental results show that the smaller the truncation factor is, the longer the characteristic length and the coherence length is, so that the beam intensity distribution is maintained integrally.