基于级联涡旋半波片的高阶柱矢量光束产生及其偏振检测

High-Order Cylindrical Vector Beam Generation and Its Polarization Detection Based on Cascade Vortex Half-Wave Plates

涡旋半波片(VHP)是一种快轴取向在空间分布上呈特定角向变化规律的偏振光学元件。通过级联两个或多个低阶VHP可以产生任意高阶柱矢量光束(CVB)。基于单个VHP的琼斯矩阵,推导了VHP级联后的等效琼斯矩阵,从理论上解释了VHP级联后等效阶数的变化规律。实验上,利用m=-1和m=2的两个VHP级联产生1阶和3阶径向偏振和角向偏振CVB,计算斯托克斯参数并绘制矢量光束偏振态分布图,并与m=1的单个VHP直接生成的CVB进行比较,证明了级联方法的可靠性。在级联VHP产生相同高阶CVB时,VHP的不同级联顺序能够影响由于中心错位而造成的光束畸变程度。经实验对比分析,得到了级联应用中能够稳定产生高质量、高阶CVB的方法,并通过级联多个VHP产生了100阶以内任意CVB。

The vortex half-wave plate(VHP)is a polarized optical element whose fast axis orientation changes in a specific angular direction in the spatial distribution.By cascading two or more low-order VHPs,any high-order cylindrical vector beam(CVB)can be generated.Based on the Jones matrix of a single VHP,the equivalent Jones matrix of the VHP cascaded is derived,and the change of the equivalent order after the VHP cascaded is theoretically explained.In the experiment,the two VHPs of m=-1 and m=2,are used to cascade to generate the one-order and three-order radial polarization and angular polarization CVBs,to calculate the Stokes parameters and draw the vector beam polarization distribution diagram,and to be compared with one-order CVBs that directly generated by the VHP of m=1,which proves the reliability of the cascade method.When the cascade produces the same high-order CVB,the different cascading sequence of the VHPs can affect the degree of beam distortion caused by the center misalignment.After experimental comparison and analysis,it is obtained that high-quality and high-order CVBs can be stably produced in the cascade application.By cascading multiple VHPs,the CVBs within 100 orders are generated.