Chiral-selective Plasmonic Metasurface Absorber Based on Bilayer Fourfold Twisted Semicircle Nanostructure at Optical Frequency

Abstract

In this paper, we demonstrate theoretically a plasmonic metasurface absorber (PMSA) for the high chiral-selective absorption for right-handed and left-handed circular polarization (RCP and LCP) lights at optical frequency. The PMSA is composed of a dielectric substrate sandwiched with bi-layer fourfold twisted semicircle nanostructure. Numerical simulation results that the proposed PMSA has a strong chiral selective absorption bands, where absorption peaks for LCP and RCP lights occur at different resonance frequencies resulting in significant circular dichroism (CD) effect. It is shown that the maximum absorbance of the PMSA can reach to 93.2% for LCP light and 91.6% for RCP light, and that the maximum CD magnitude is about 0.85 and 0.91 around 288.5 THz and 404 THz, respectively. The mechanism of the strong chiroptical response of the PMSA is illustrated and revealed by electric fields distributions. Furthermore, the influence of the geometry of the proposed PMSA on the chiral-selective absorption characterization is studied systematically. Due to the strong chiral-selective absorption and CD effect, the proposed PMSA can be found many potential applications in some areas, such as chiral imaging, optical filters, detecting, and optical communications.PACS numbers: 42.25.Bs, 78.20.−e