分数阶涡旋光的特性研究及其实验分析

Research on the Characteristics of Fractional Vortex Beam and Experimental Analysis

分数阶涡旋光其拓扑荷为分数、拥有独特的径向缺口且具有更多的控制参数,因而受到了越来越多的关注。基于衍射积分理论推导出分数阶涡旋光的光场表达式,利用MATLAB软件对其光强分布和相位分布进行了仿真研究。仿真结果表明,光斑的径向缺口大小与拓扑荷值小数部分有关,拓扑荷值小数部分越接近半整数,径向缺口越明显;随着拓扑荷整数部分的增大,光斑半径也增大。文章采用反射式纯相位型液晶空间光调制器产生多个拓扑荷为半整数的涡旋光进行实验验证,图像传感器采集到的传输光斑与理论仿真结果一致。

Fractional vortex light has fractional topology charge, unique radial gap, and relatively many control parameters, which has attracted much attention recently. Based on the diffraction integral theory, the light field expression of fractional order vortex light is derived in the paper. In addition, simulation is conducted on the light intensity distribution and phase distribution with MATLAB. The simulation results show that the radial gap size is related to the decimal part of topological charge value. To be specific, when the decimal part of topological charge value is closer to half integer, the radial gap is more obvious. Moreover, with the increase of the integer part of topological charge, the light spot radius increases. In this paper, a variety of vortex light with topological charge being half integer is produced through reflective type of liquid crystal spatial light modulator. The transmission light spot collected by CCD is consistent with the simulation results of the paper.