Angular Momenta and Spin-Orbit Interaction of Nonparaxial Light in Free Space

TL;DR

This paper provides a comprehensive operator-based framework for analyzing the spin and orbital angular momenta, as well as spin-orbit interactions, of nonparaxial light in free space, with applications to Bessel beams and observable phenomena.

Contribution

It introduces an exact, self-consistent operator formalism for nonparaxial light, combining quantum and classical approaches, and applies it to specific beam types with experimental implications.

Findings

Exact wave solutions interpreted via Berry phases and caustic quantization

Identification of Hall effects of light in nonparaxial regimes

Analysis of spin- and orbital-dependent intensity profiles

Abstract

We give an exact self-consistent operator description of the spin and orbital angular momenta, position, and spin-orbit interactions of nonparaxial light in free space. Both quantum-operator formalism and classical energy-flow approach are presented. We apply the general theory to symmetric and asymmetric Bessel beams exhibiting spin- and orbital-dependent intensity profiles. The exact wave solutions are clearly interpreted in terms of the Berry phases, quantization of caustics, and Hall effects of light, which can be readily observed experimentally.