Spin control of light with hyperbolic metasurfaces

TL;DR

This paper demonstrates that hyperbolic metasurfaces enable engineering the spin angular momentum of surface waves to have arbitrary angles, facilitating magnetic control of wave directionality and spin transfer at the nanoscale.

Contribution

It introduces the concept of controlling the spin of hybrid surface waves on hyperbolic metasurfaces, allowing arbitrary spin angles and enhanced optically controlled spin transfer.

Findings

Surface wave spin can be engineered to have arbitrary angles.

Hyperbolic metasurfaces enable magnetic control of wave directivity.

Potential applications in nanoscale optomechanics and spintronics.

Abstract

Transverse spin angular momentum is an inherent feature of evanescent waves which may have applications in nanoscale optomechanics, spintronics, and quantum information technology due to the robust spin-directional coupling. Here we analyze a local spin angular momentum density of hybrid surface waves propagating along anisotropic hyperbolic metasurfaces. We reveal that, in contrast to bulk plane waves and conventional surface plasmons at isotropic interfaces, the spin of the hybrid surface waves can be engineered to have an arbitrary angle with the propagation direction. This property allows to tailor directivity of surface waves via the magnetic control of the spin projection of quantum emitters, and it can be useful for optically controlled spin transfer.