Near-complete photon spin selectivity in a metasurface of anisotropic plasmonic antennas

Abstract

Simple chiroptically active metamaterials are difficult to realize in practice but could pave the way for a range of important applications, such as sensitive optical biosensors, asymmetric catalysis, and novel polarization manipulation devices. We show that a metasurface based on a random arrangement of anisotropic but aligned gold nanoparticles can exhibit an almost perfect selectivity towards incident photon spin for evanescent excitation with visible to near-infrared light. The experimentally attained reflection contrast between left- and right-handed circularly polarized light peaks at ~90%, in excellent agreement with analytical theory. These results are important for the development of future photonic and plasmonic polarization-based technologies.