Properties of Spin and Orbital Angular Momenta of Light

TL;DR

This paper explores the algebraic and physical properties of light's spin and orbital angular momenta within quantum mechanics, revealing their non-traditional characteristics and implications for photon modes and classical fields.

Contribution

It provides a detailed analysis of the quantum properties of light's angular momenta, highlighting their non-standard eigenvalues and implications for mode definitions.

Findings

Spin angular momentum has continuous eigenvalues.

Analysis of Laguerre-Gaussian modes with polarization.

Implications for classical light field descriptions.

Abstract

This paper analyzes the algebraic and physical properties of the spin and orbital angular momenta of light in the quantum mechanical framework. The consequences of the fact that these are not angular momenta in the quantum mechanical sense are worked out in mathematical detail. It turns out that the spin part of the angular momentum has continuous eigenvalues. Particular attention is given to the paraxial limit, and to the definition of Laguerre--Gaussian modes for photons as well as classical light fields taking full account of the polarization degree of freedom.