Diehl, D. W. Schoonover, R. W. Visser, T. D. Media 1: The structure of focused, radially polarized fields Originally published in Optics Express on 03 April 2006 (oe-14-7-3030) media;oe;radially;Optics Express;03 April 2006 2006-04-03
    https://opticapublishing.figshare.com/articles/media/Media_1_The_structure_of_focused_radially_polarized_fields/4935674
10.1364/OE.14.003030.m001