Hybrid bilayer plasmonic metasurfaces with intrinsic chiral optical responses

Abstract

Plasmonic metasurfaces with giant chiral optical responses are good candidates for chirality study and application, which are usually composed of few-layer or three-dimensional nanostructures. Here, we demonstrate that hybrid bilayer plasmonic metasurfaces simply fabricated via a facile one-step nanofabrication process are good candidates for the realization of intrinsic chiral optical responses and spin-selective transmission. We prove that the intrinsic chiral optical response of the proposed metasurface, which can be easily manipulated, is attributed to the spin-selective collective interference of locally enhanced electric fields caused by the strong interlayer coupling. We further experimentally prove the advantages of fabricated hybrid bilayer plasmonic metasurfaces for optical encryption. With the advantages of compact design, chiral optical response easy to control and lower fabrication demand, the proposed metasurfaces can further expand the applications of chiral plasmonic nanostructures in the area of spin nanophotonics, nonlinear optics, and optical sensing.