Spatial splitting of spin states in subwavelength metallic microstructures via partial conversion of spin-to-orbital angular momentum

Abstract

We theoretically and numerically investigate the interaction of an electromagnetic wave with structured metamaterial under the excitation of linearly polarized light. A polarization map of the transmitted electromagnetic wave can reveal electromagnetic spin-to-orbital angular momentum conversion. The spatial splitting of spin states described by the Stokes parameter ${S}_{3}$ may be viewed as the photonic version of a Stern-Gerlach experiment in the absence of a magnetic field. Our idea is ideally suitable for demonstration of electromagnetic spin-to-orbital angular momentum conversion, which offers an alternative way to comprehend the conversion. Moreover, it could enrich a variety of optical phenomena in subwavelength structured metallic systems.