Generation of the periodically polarized structured light beams

We report a kind of structured light beam with periodical polarization and phase singularities. It is generated from a setup consisting of conical refraction transformation and 4f-system. By this setup, the periodical structures are produced without any change of intensity distributions. We analyze both theoretically and experimentally the polarization and phase structures of the periodically structured light beam. The dependence of period is demonstrated on the length of crystal and the focal length. It is shown that the polarization of the input beam can be used to control the polarization and phase structures of the output beam.