Paraxial Light Beams with Angular Momentum

TL;DR

This paper reviews the fundamental and applied aspects of light beams carrying angular momentum, including their properties, generation methods, and potential applications in optical manipulation and measurement.

Contribution

It provides a comprehensive overview of the concepts, mechanisms, and phenomena related to angular momentum in paraxial light beams, highlighting recent research developments and future prospects.

Findings

Analysis of spin and orbital angular momentum components

Discussion of generation methods for spiral beams

Exploration of rotational Doppler effects and applications

Abstract

Fundamental and applied concepts concerning the ability of light beams to carry a certain mechanical angular momentum with respect to the propagation axis are reviewed and discussed. Following issues are included: Historical reference; Angular momentum of a paraxial beam and its constituents; Spin angular momentum and paradoxes associated with it; Orbital angular momentum; Circularly-spiral beams: examples and methods of generation; Orbital angular momentum and the intensity moments; Symmetry breakdown and decomposition of the orbital angular momentum; Mechanical models of the vortex light beams; Mechanical action of the beam angular momentum; Rotational Doppler effect, its manifestation in the image rotation; Spectrum of helical harmonics and associated problems; Non-collinear rotational Doppler effect; Properties of a beam forcedly rotating around its own axis. Research prospects and ways of practical utilization of optical beams with angular momentum.