Egorov Y. "Fine structure of monochromatic and polychromatic singular beams in an uniaxial crystal"

Theoretical and experimental research is presented of generation and control of optical vortices in optical systems with uniaxial crystals, polarizations filters half-wave plate is given. Both coherent and polychromatic beams are considered. It is shown an uniaxial crystal can sufficiently transform the structure of the beam with giving birth to a vortex with the topological charge differing from the initial one by two units. The sign of the charge of the resulting beam is shown to be determined by the charge and the rotation of the initial beam. Analysis of the fine structure of the beam demonstrated that half-wave plate and polarizer enable a control of the optical vortex. It is shown that a joint effect of polarization filter and crystals produces a polychromatic vortex with the double charge on its axis and slightly deformed core.