亚波长径向偏振光栅的设计

针对现有电力光学电流传感中法拉第旋转角的非线性测量、解调模式的光强依赖性等问题，本文设计了一种环型亚波长偏振光栅，其光栅矢量径向分布，可将偏振光的偏振分布转化为光斑强度分布并与偏振面同步旋转。应用琼斯矩阵对其偏振特性进行分析，运用严格耦合波理论对光栅进行仿真分析与优化设计，并制备了辐射状的环型铝金属光栅。测试结果表明，光栅TM光的透过率大于80%、整体消光比大于100，可实现对光偏振态的直接检测，并具有线性测量范围大、测量结果不依赖于光的绝对强度等优点，可用于基于图像分析的偏振检测技术。

Design of sub-wavelength radially polarized grating

A new type of radially polarized grating is designed to solve the problems of nonlinear measurement of Faraday rotation existing in the power optical sensing. The distribution of the grating vector is in accordance with the special method, so that the polarization distribution of the polarized light can be transformed into the distribution of light intensity, which rotates synchronously with polarization plane. The theory of polarization detection is analyzed by using Jones matrix, and the parameters of the grating are simulated by rigorous coupled wave theory. Finally, the grating is fabricated and tested. The results show that the TM transmittance of the grating is greater than 80%, the extinction ratio is greater than 100, and the detection of the polarization state can be realized. It has the advantages of large linear measurement range and measurement results independent on the absolute intensity, so that it will be a new detection technology of polarization based on the image method.