部分相干离轴涡旋光束在大气湍流中的光强分布

Intensity Distribution of Partially Coherent Off-Axis Vortex Beam Propagating in Atmospheric Turbulence

根据广义惠更斯-菲涅耳原理以及交叉谱密度函数,利用Kolmogorov湍流谱推导得到部分相干离轴涡旋光束在大气湍流中传输时光束的光强分布表达式,讨论了离轴距离、拓扑荷数、束腰宽度、相干长度、传输距离、湍流强度参数对光强分布的影响。仿真结果表明,拓扑荷数的大小不会改变暗核的位置;离轴距离的正负号决定了暗核移动的方向和光强集中区域的方向;暗核向上移动的距离随相干长度、束腰宽度的增大而减小,随传输距离、湍流强度的增大而增大;光斑展宽随相干长度、束腰宽度、传输距离、湍流强度的增大而增大。

Based on the generalized Huygens-Fresnel principle and the cross spectral density function,we deduce the expression of intensity distribution of partially coherent off-axis vortex beams propagating in atmospheric turbulence by using the Kolmogorov turbulence spectrum.The effects of off-axial distance,topological charge,waist width,coherent length,transmission distance,turbulence intensity on the intensity distribution are discussed.Simulation results show that the topological charge does not change the position of the dark core.The sign of off-axial distance determines the direction of the dark core movement and the direction in which the intensity is concentrated.The upward movement distance of the core decreases with the increase of the waist width and the coherent length,and increases with the increase of the transmission distance and the turbulence intensity.The spreading of beam increases with the increase of the waist width,the coherent length,the transmission distance and the turbulence intensity.