Radial and azimuthal polarizer by means of a birefringent plate

In this paper an optical system is proposed to generate radially and azimuthally polarized beams. A focused monochromatic beam is divided into ordinary and extraordinary parts by using a thin plane parallel uniaxial crystal plate. If the optical axis of the crystal is perpendicular to its surface, the two generated foci can be associated with azimuthal and radial polarization states, respectively. The generated foci were studied theoretically and experimentally using a focusing objective with a moderate numerical aperture (NA = 0.45) and different kinds of uniaxial crystal.