Investigation on the characteristics of speckle produced by radially polarized vortex beams through scattering medium

In this paper, we studied the properties of speckle, which is produced by passing the radially polarized vortex beams through the scattering medium. We first of all study the generation of the radially polarized vortex beams. The experimental results show that the generated light beams possess the orbital angular momentum (OAM) and the polarization is of radial direction. The radially polarized vortex beams with topological charge zero, 2, or 4, and 6 are obtained by the radial polarization convertor and the spiral phase plate. Then we investigate the speckle properties of these light beams passing through the scattering medium with different sizes of the scattering media particles. The speckle properties is numerically simulated, the related parameters of speckle also are measured, for example, the size of the speckle. Both theoretical and experimental results show that, the size of the speckle formed by the radially polarized beam is smaller than the size of the speckle formed by the non-radially polarized beam, the size of the speckle decreases with the increasing topological charge of radially polarized vortex beams, and the decreasing size of the scattering medium particle. At the same time, we also study the generation of partially coherent vortex light beams, and investigate the speckle properties produced by passing partially coherent vortex light beams through the scattering medium. It is shown that the lower coherence of the light beams will result in the contrast of the speckle. Both theoretical and experimental results of this paper may find applications in laser display et al‥