In this paper, we present a plasmonic chiral metasurface absorber (CMSA), which can achieve the high selective absorption for right-handed and left-handed circular polarization (RCP, “+”, and LCP, “-”) lights at optical frequency. The CMSA is composed of a dielectric substrate sandwiched with bi-layer fourfold twisted semicircle metal nanostructure. The proposed CMSA has a strong selective absorption band, where absorption peaks for LCP and RCP lights occur at different resonance frequencies, reflecting the existence of a significant circular dichroism (CD) effect. It is shown that the absorbance of the CMSA can reach to 93.2% for LCP light and 91.6% for RCP light, and that the maximum CD magnitude is up to 0.85 and 0.91 around 288.5 THz and 404 THz, respectively. The mechanism of the strong chiroptical response of the CMSA is illustrated by electric fields distributions of the unit-cell nanostructure. Furthermore, the influence of the geometry of the proposed CMSA on the circular polarization selective absorption characterization is studied systematically.

A broadband metamaterial absorber (MMA) with optical transmittance property was designed to address the electromagnetic (EM) pollution in gigahertz (GHz). The proposed MMA with high optical transmittance polymethyl methacrylate (PMMA) between a periodic arrayed indium tin oxide (ITO) film and a low-resistivity ITO reflective layer. Over 90% microwave absorbance can be achieved in the frequency range of 6-17.8 GHz and three distinct absorption peaks can be found in the reflection spectrum. The results also show wide-angular stability, good polarization insensitiveness, and optical transmittance properties. The microwave attenuation mechanisms of the proposed MMA were investigated using surface current distribution and power loss density. The excellent microwave absorption and optical transmittance properties indicate that the designed MMA has strong potential for developing optical transmittance microwave absorption windows and devices.

No abstract

No 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