Evolution of a circularly polarized beam bearing an optical vortex with fractional topological charge in a uniaxial crystal

摘要

We show that when a beam propagates through a uniaxial crystal, the resultant spin-orbit coupling gives rise to oscillations in the projected spin and the orbital angular momentum flux. We find that the handedness of the beam reverses with increasing angle between the axis of the crystal and the optical axis of a circularly polarized beam bearing an optical vortex with fractional topological charge l = 1/2. The spin angular momentum is converted into orbital angular momentum, and the topological charge doubles to l = 1. We describe the processes for creation and annihilation of polarization singularities in a beam bearing an optical vortex with fractional topological charge. We construct evolutionary trajectories for polarization singularities in a circularly polarized Gaussian beam bearing an optical vortex with fractional topological charge in a uniaxial crystal. (C) 2017 Optical Society of America