为了研究椭圆偏振拉盖尔?高斯光经超表面的聚焦特性，重点分析了聚焦光场的电场强度以及相位分布特性。利用时域有限差分（FDTD）方法仿真椭圆偏振拉盖尔?高斯光经超表面的聚焦光场。研究表明，椭圆偏振拉盖尔?高斯光经超表面聚焦后会在聚焦光场的纵向分量电场中出现自旋角动量转化为轨道角动量的现象，通过改变超表面的数值孔径大小、拉盖尔?高斯光的偏振类型等参数可以调控涡旋光场形态分布。该现象可应用于光镊、量子加密、光学扳手等技术中。

In order to study focusing field properties of elliptically polarized Laguerre-Gaussian beam passing through the metasurface with high numerical aperture, the electric field intensity and phase distribution characteristics of the focused beam field are analyzed. finite difference time domain (FDTD) method is used to simulate the field distribution of elliptically polarized Laguerre-Gaussian beam passing through the metasurface. The research demonstrates that the elliptically polarized Laguerre-Gaussian beam can convert the spin angular momentum into the orbital angular momentum in the focal area with longitudinal electric field component with the metasurface. By changing a series of parameters such as the numerical aperture of the metasurface and the polarization of the Laguerre-Gaussian beam, the vortex focusing field distribution can be manipulated. Our work provides a method for the application of Laguerre- Gaussian beam in the field of ultra-compact beam manipulations devices with optical tweezers, quantum encryption, optical wrench.