Tight focusing of a nonhomogeneously polarized optical vortex

In this work, we fabricated and studied the performance of a 100×100-μm four-sector binary subwavelength grating polarizer in a golden film. It was experimentally demonstrated that a linearly polarized 532-nm Gaussian beam reflected at the polarizer was converted to an azimuthally polarized beam. Putting a spiral phase plate (SPP) with the topological charge n = 1 into the azimuthally polarized beam from the micropolarizer was experimentally shown to enable the conversion of the annular intensity pattern into a central intensity peak.