Poynting vector and orbital angular momentum density of superpositions of Bessel beams

Abstract

The authors study theoretically the orbital angular momentum (OAM) density in arbitrary scalar optical fields, and outline a simple approach using only a spatial light modulator to measure this density. They demonstrate the theory in the laboratory by creating superpositions of nondiffracting Bessel beams with digital holograms, and find that the OAM distribution in the superposition field matches the predicted values. Knowledge of the OAM distribution has relevance in optical trapping and tweezing, and quantum information processing.