Intensity modulation of a tightly focused partially coherent and radially polarized beam

Because of the circular symmetry of a completely coherent radially polarized beam, the azimuthal intensity component is zero when it is focused by a high numerical aperture (NA) objective. In this paper, we show that such a conclusion is not tenable under the illumination of partially coherent beam whose coherent property depends on the azimuthal angle. Taking the Gaussian Schell-model (GSM) beam for an example, the tight focusing property of a partially coherent beam is studied, and the intensity and its radial, azimuthal and longitudinal components are particularly researched. The results show that the percentage of the components on the total intensity depends on the correlation length of the partially coherent beam. The azimuthal intensity component is produced under the illumination of partially coherent beam. © 2013 Tianjin University of Technology and Springer-Verlag Berlin Heidelberg.