2D shift of the centre of gravity of the light beam carrying orbital angular momentum, which accompanies reflection from a lossy medium

TL;DR

This paper demonstrates that a paraxial light beam with orbital angular momentum experiences a two-dimensional shift in its center of gravity after reflecting from a lossy medium, with the shift components linked to the beam's polarization and complex parameters.

Contribution

It introduces a novel analysis of the 2D shift of light beams with orbital angular momentum upon reflection from lossy media, relating the shift to complex quantities and polarization states.

Findings

The 2D shift depends on the real and imaginary parts of a complex quantity.

The shift components are orthogonal and related to the beam's polarization.

Features of the shift vector are thoroughly analyzed.

Abstract

It is shown that after reflection from a lossy medium the $s$- or $p$-polarized paraxial light beam carrying the orbital angular momentum suffers the 2D shift of the beam's centre of gravity relative the geometric optic axis. The mutually orthogonal components of this shift are expressed through the real and imaginary parts of the common complex quantity. The features of the 2D vector, which describes the shift, are analyzed.