Spin-induced angular momentum switching

TL;DR

This paper analyzes how light's angular momentum can be manipulated using inhomogeneous media, revealing a new modulation effect that enables spin-controlled changes in orbital angular momentum.

Contribution

It provides a complete paraxial analysis of spin-induced angular momentum switching and uncovers a novel modulation effect in optical phase plates.

Findings

Demonstration of spin-controlled orbital angular momentum change

Identification of a strong modulation effect with optical path variation

Potential applications in light manipulation and optical devices

Abstract

When light is transmitted through optically inhomogeneous and anisotropic media the spatial distribution of light can be modified according to its input polarization state. A complete analysis of this process, based on the paraxial approximation, is presented, and we show how it can be exploited to produce a spin-controlled-change in the orbital angular momentum of light beams propagating in patterned space-variant-optical-axis phase plates. We also unveil a new effect. The development of a strong modulation in the angular momentum change upon variation of the optical path through the phase plates.