基于矢量衍射理论，研究了连续型相位光瞳滤波器对径向偏振光束在焦点区域成像效果的影响。设计了一种余弦函数形式的连续相位型光瞳滤波器，实现了缩小径向偏振光束的横向焦斑。利用Matlab优化工具箱，以超分辨性能参数G为优化目标，以斯特雷尔比S为约束条件，对余弦函数形式的连续相位型光瞳滤波器进行优化并给出了几组优化结果。优化结果表明所设计的余弦函数形式的连续相位型光瞳滤波器在数值孔径为0.8时对于缩小径向偏振光横向焦斑有明显的效果。关于此种连续相位光瞳滤波器的计算结果，对实际中制作相位光瞳滤波器有一定参考价值。

Based on vectorial diffraction theory, optical imaging system with continuous phase optical pupil filter for radially polarized beam is investigated. A continuous phase filter with cosine function is proposed and a sharper focus of radially polarized beam is obtained. This kind of filter is optimized with Matlab optimization toolbox and the aim of optimization is to reduce the superresolution parameter G with the Strehl ratio S as a constraint. Some examples of optimization are given. The optimization results show that there is a significant improvement on sharper focus by using this continuous phase filter with cosine function when the numerical aperture is 0.8. The numerical results about the continuous phase filter with cosine function will also help the manufacturing of actual devices.