Spin-to-orbital angular momentum conversion in spin Hall effect of light

TL;DR

This paper investigates how spin-to-orbital angular momentum conversion influences the spin Hall effect of light, showing that refractive index gradients and metamaterials can control and enhance this phenomenon.

Contribution

It introduces a clear separation of spin and orbital angular momenta in the SHE of light and proposes using metamaterials to manipulate the effect.

Findings

Refractive index gradient affects spin-to-orbital angular momentum conversion.

Metamaterials can be designed to amplify or suppress the SHE of light.

Transverse shifts are governed by spin-to-orbital angular momentum conversion.

Abstract

From the viewpoint of classical electrodynamics, we identify the role of spin-to-orbital angular momentum conversion in spin Hall effect of light (SHE). We introduce a distinct separation between spin and orbital angular momenta to clarify the spin-orbital interaction in the SHE of light. We demonstrate that the refractive index gradient can enhance or suppress the spin-to-orbital angular momentum conversion, and thus can control the SHE of light in conventional beam refraction. We suggest that the metamaterial whose refractive index can be tailored arbitrarily may become a good candidate for amplifying or eliminating the SHE of light, and by properly facilitating the spin-to-orbital angular momentum conversion the SHE may be enhanced dramatically. The transverse shifts governed by the spin-to-orbital angular momentum conversion, provide us a clear physical picture to clarify the role of refractive index gradient in the SHE of light. These findings provide a pathway for modulating the SHE of light and can be extrapolated to other physical systems.