Spin Hall Effect of Light with Near‐Unity Efficiency in the Microwave

Abstract The spin Hall effect of light (SHEL) refers to a transverse and spin‐dependent shift of light in real space at an optical interface. Previous studies of enhancing the SHEL have involved extremely low efficiency, and achieving a large SHEL and high efficiency simultaneously has never been reported. Here, an approach using anisotropic impedance mismatching to attain a large SHEL with near‐unity efficiency in the microwave spectrum is proposed. A wire medium that has a near‐unity transmission for one polarization and low transmission for the other is used to achieve high efficiency. The spin‐dependent splitting is experimentally confirmed by measuring transmission coefficients and the spatial profile of Stokes parameters. The large SHEL with near‐unity efficiency will enable highly efficient devices with spin‐selective functionalities.