Angular momentum and geometrical phases in tight-focused circularly polarized plane waves

Calculations for the field at the focal plane of a high numerical aperture lens focusing a circularly polarized plane wave are presented. The calculations show that the polarization of the wave front in the focal plane is space varying, and that a geometrical phase is added to the wave front. Calculation of the angular momentum at the focal plane reveals that it depends on the numerical aperture of the lens. It is shown that this dependence is directly connected to the lens acting as a spatial filter.