An electron scattering scheme is proposed to explore and quantify the focal field of radially polarized beam (RPB). Based on the Richard-Wolf method we deduce the description of the RPB's focal field, analyze the interaction and motion of the electrons in the focal field of the RPB, using both electrodynamical and pondermotive method. Our results show that the geometrical and field information of RPB focus are included in the electron scattering patterns which can be measured easily by experiment. Then we develop and demonstrate an experimental scheme to probe the RPB focal field by electron beam scattering, whose results agree well with the theoretical conclusions. Our scheme is also available for analyzing other cylindrically polarized beams.

提出了一种电子散射方案来探索和量化径向偏振光束（RPB）的焦点。基于Richard-Wolf方法，我们推导了RPB聚焦场的描述，并使用电动力法和质动力法分析了RPB聚焦场中电子的相互作用和运动。我们的结果表明，RPB焦点的几何和场信息包含在电子散射图中，可以通过实验轻松测量。然后，我们开发并演示了一种通过电子束散射探测RPB焦点的实验方案，其结果与理论结论相吻合。我们的方案也可用于分析其他圆柱偏振光束。