On the vectorial structure of non-paraxial radially polarized light fields

To describe in a detailed way the polarization features of non-paraxial radially polarized fields, a simple analytical propagation law is provided in terms of their angular plane-wave spectrum. A comparison between non-paraxial results and paraxial predictions is investigated by introducing a parameter describing the width of the angular spectrum. Two particular examples of radially polarized light fields are also considered: Bessel-type fields whose angular spectrum is confined on a Montgomery's ring, and certain radially polarized Laguerre-Gauss beams.