Pancharatnam--Berry phase in space-variant polarization-state manipulations with subwavelength gratings

Opt Lett. 2001 Sep 15;26(18):1424-6. doi: 10.1364/ol.26.001424.


We report the appearance of a geometrical phase in space-variant polarization-state manipulations. This phase is related to the classic Pancharatnam-Berry phase. We show a method with which to calculate it and experimentally demonstrate its effect, using subwavelength metal stripe space-variant gratings. The experiment is based on a unique grating for converting circularly polarized light at a wavelength of 10.6 mum into an azimuthally polarized beam. Our experimental evidence relies on analysis of far-field images of the resultant polarization.