拉盖尔-高斯光束在湍流大气中的螺旋谱特性

研究了拉盖尔-高斯光束在湍流大气中的传输特性.在利托夫近似下,得到接收孔径处光束的螺旋谱的积分表达式.通过数值仿真得出大气湍流对光束螺旋谱的影响以及光束螺旋谱随各参数值的变化特性.仿真发现大气湍流会使螺旋谱发生弥散.而且随着拓扑荷,接收孔径半径,折射率结构函数及距离的增加,螺旋谱弥散加剧.经拟合得到描述螺旋谱弥散程度的无量纲方差V随距离成6次函数关系;与接收孔径半径及折射率结构函数成二项式关系;而与拓扑荷呈11次多项式关系.最后得出径向指数,束腰半径对螺旋谱的影响非常小,并且根据此结论推出光 关键词： 拉盖尔-高斯光束 大气湍流 螺旋谱 无量纲方差

Spiral spectrum of Laguerre-Gaussian beams propagating in turbulent atmosphere

An analysis of the propagation of Laguerre-Gaussian beam in fluctuation turbulent atmosphere is performed. Under the Rytov approximation, the integral expression of the spiral spectrum of the beam at the receiver aperture is obtained. It is found that the atmospheric turbulence will induce the spread of the spiral spectrum. With increasing topological charge, propagation distance, refractive index structure constant and radius of receiver aperture, the spectrum spread becomes more serious. It is also shown that the dimensionless variance describing the degree of the spread is a quadratic function of the refractive index structure constant and the radius of receiver aperture respectively, while it is an 11th order function of the topological charge and a 6th order function of the propagation distance. The analytical expression of the spiral spectrum is derived by taking account of the simulation results that both radial index and waist radius have little effect on the spiral spectrum.