柱坐标下的径向偏振矢量光束在被高数值孔径透镜聚焦时，在紧聚焦条件下相比线偏振和圆偏振光束通过透镜后能获得较小的聚焦斑。在聚焦透镜前加上椭圆环光阑后能强化在聚焦区域内的光场轴向分量，能在单一方向上进一步缩小聚焦斑的尺寸。研究了径向偏振矢量光束经过椭圆环形光阑后的聚焦特性，在聚焦区域径向偏振分量形成两个聚焦瓣，而轴向分量形成椭圆形的聚焦斑,并做了相应的物理解释。当增加椭圆环形光阑内环半径时，径向偏振分量的聚焦瓣和轴向分量的聚焦斑单一方向聚焦尺寸均可小于光波长的三分之一，当进一步提高椭圆环形光阑内环半径时，由于通光量减少和衍射效应，不能得到更小的聚焦尺寸。研究结果对于提高激光扫描显微镜的单向分辨率具有重要意义。

When the radial polarization vector beam is focused by a high numerical aperture lens, compared with the linear polarization light and the circular polarized light cases, a smaller focused spot can be obtained by the radial polarization vector beam. An elliptic annular aperture can enhance the axial component of light in the focus area. So the focus spot size can be further reduced in one direction. The focusing characteristics of the radial polarization vector beam passing through an elliptic annular aperture are studied. Two focusing lobes are obtained by the radial polarization component of light. An elliptical focusing spot is obtained by the axial component of light and the corresponding physical explanation is given. When the inner radius increases, the focus size of the focusing spot and focusing lobes can be less than one third of the wavelength in one direction. When the inner ring radius of the elliptic annular aperture is further improved, a smaller focus size of light can’t be obtained as the decrease of light and the diffraction effect. The results of the study are important for improving one direction resolution of laser scanning microscope.