Polarization structure of optical vortices in inclined Laguerre-Gaussian beams passed through a uniaxial crystal.

The work shows that in linearly polarized Laguerre-Gaussian beams passing through an anisotropic medium at an angle to the optical axis of the crystal, the distribution of optical vortices is devoid of axial symmetry. It is shown that the trajectories of movement of polarization singularities in the plane of the Laguerre-Gauss beam are different for different cases of input linear polarization at angles =±45 and there is an exchange of optical vortices, provided that the sign of the topological charge is preserved. It is shown that when the axis of an anisotropic medium is tilted, the movement of optical vortices occurs, accompanied by topological reactions of creation, destruction, or displacement of optical vortices to the periphery of the beam.

Transmission of fractional topological charges via circular arrays of anisotropic fibers.

We demonstrate that in circular arrays of anisotropic fibers at certain distribution of anisotropy directors robust transmission of optical fields with half-integer topological charges is possible. We show that this is possible because the supermodes of such arrays may contain in their circularly polarized components half-integer topological charges of opposite values. We also study the structure of singularities in these supermodes.

Vector erf-Gaussian beams: fractional optical vortices and asymmetric TE and TM modes.

We have considered the paraxial vector erf-Gaussian beams with field distribution in the form of the error function that are shaped by the cone of plane waves with a fractional step of the azimuthal phase distribution modulated by the Gaussian envelope. We have revealed that the initial distributions of the transverse electric and transverse magnetic fields have a far from standard form but at the far diffraction field the field distributions recover nearly the symmetric form.

Rotational spin Hall effect in a uniaxial crystal.

We have considered the propagation process of the phase-matched array of singular beams through a uniaxial crystal. We have revealed that local beams in the array are rotated when propagating. However the right and left rotations are unequal.

Subwave spikes of the orbital angular momentum of the vortex beams in a uniaxial crystal.

We have theoretically predicted gigantic spikes of orbital angular momentum caused by conversion processes of the centered optical vortex in the circularly polarized components of an elliptic vortex beam propagating perpendicularly to the crystal optical axis. We have experimentally observed the conversion process inside subwave deviations of the crystal length. We have found that the total orbital angular momentum of the wave beam is conserved.