Rotational spin Hall effect in a uniaxial crystal

TL;DR

This paper investigates the rotational spin Hall effect in a uniaxial crystal, revealing how singular beam arrays rotate asymmetrically due to interference and depolarization, with rotation direction tied to initial polarization handedness.

Contribution

It introduces the concept of the rotational spin Hall effect caused by depolarization and interference in uniaxial crystals, highlighting the asymmetry and polarization dependence of array rotation.

Findings

Local beams in the array rotate during propagation.

The rotation is asymmetric, with different left and right rotations.

Rotation direction depends on initial circular polarization handedness.

Abstract

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. There are at least two processes responsible for the array rotation: the interference of local beams and the spatial depolarization. The interference takes place in the vortex birth and annihilation events forming the symmetrical part of the rotation. The depolarization process contributes to the asymmetry of the rotation that is called the rotational spin Hall effect. It can be brought to light due to the difference between the envelopes of the dependences of the angular displacement on the inclination angle of the local beams or the crystal length reaching the value some angular degree. The direction of the additional array rotation is exclusively defined by the handedness of the circular polarization in the initial beam array.