Metasurfaces for spin-control of surface waves

Abstract

Metasurfaces have been studied extensively in recent years as important platforms for controlling and guiding electromagnetic waves. In this paper, we introduce two metasurface designs that allow for controlling and steering different polarizations (spins) of surface waves. We also study a new type of surface waves that is supported by an L-shape design called chiral surface waves which are circularly polarized waves that possess two transverse spins. The spin direction is locked to the momentum of the surface wave which results in splitting it into two waves propagating in two different directions based on their helicity when excited with a linearly polarized source. This work provides a new way for manipulating the spin-orbit interaction of electromagnetic waves propagating along the surface. Controlling the spin-orbit interactions of electromagnetic waves is of great importance for applications in spintronics and valleytronics. Additionally, the surface modes supported by the presented metasurface designs have high self-collimation which can be used for polarization-based beam steering, spin filtering and surface wave guiding with the advantage of using homogeneous designs.