拉盖尔－高斯涡旋光束传播中的相位变化分析

摘要

为了研究拉盖尔－高斯涡旋光束在传播过程中的相位特性，采用螺旋相位板法获取涡旋光束，从菲涅耳衍射积分出发，对光束在传输过程中的相位变化以及整数阶与分数阶涡旋光束相位奇点的稳定性进行了理论推导和数值模拟。当光束传输一段距离后，光场在观察平面上的等相位线由发散的射线变成了花瓣状的弧线。结果表明，拓扑荷为整数阶的涡旋光束在传输过程中，相位奇点具有稳定性，而分数阶光束的相位奇点不再保持稳定性，其观察平面的光强分布不对称，且涡旋光束中心为暗核的特点消失。该结论对光学微操纵和光信息编码技术的实现具有理论指导意义。%In order to study the phase characteristics of Laguerre-Gaussian vortex beam during propagation , the vortex beam was obtained by means of spiral phase plates .Based on Fresnel diffraction integral formula , the phase change of the beam in the propagation process and the stability of vortex beam phase singularities at integer order and fractional order were studied by theoretical derivation and numerical simulation .When the beam was transmitted a certain distance , phase contours of the light field on the observation plane became from diverging rays into petal-shaped arcs .The results show that if topological charge of the vortex beam is integer order , the phase singularity of the beam assumes stability in the propagation process .The phase singularity of fractional order is unstable , intensity distribution on the observation plane is obvious asymmetric and the central darkness gradually disappears .The research results supply theoretical foundation and practical guidance for the application of optical micro manipulation and information coding techniques .