Generation of perfect polarization vortices using combined gratings in a single spatial light modulator.

Perfect polarization vortices (PPVs) are a type of vector beam with a diameter independent of the polarization order. In this paper, an experimental method is proposed to generate PPVs with an anisotropic polarization distribution. First, a specially designed hologram is generated on a liquid-crystal spatial light modulator (SLM) to obtain Bessel-Gaussian (BG) beams. Second, the BG beams are transformed into PPVs in the Bessel region by an interferometer, which includes a polarized beam splitter, two reflectors, and several lenses. In our experiment, PPVs with adjustable polarization orders and diameters are obtained by generating various combined holograms on the SLM.