Multiband selective absorbers made of 1D periodic Ag/SiO2/Ag core/shell coaxial cylinders horizontally lying on a planar substrate.

Abstract

In this paper, we present a one-dimensional periodic microstructure for multiband selective absorbers of thermal radiation. The microstructure is made of Ag/SiO2/Ag core/shell coaxial cylinders horizontally lying on top of a SiO2 dielectric spacer and an opaque silver substrate. The spectral-directional absorptivity of the proposed structure was numerically investigated with the finite element based Comsol Multiphysics software. Multiband selective absorption in the wavenumber range from 2500 to 20000 cm-1 for TM-wave incidence was obtained. Physical mechanisms responsible for the multiband selective absorption were elucidated due to the resonance of magnetic polaritons in the SiO2 spacer shell, excitation of surface plasmon polaritons at the SiO2/Ag interface, and the effect of Wood's anomaly. Furthermore, the effects of a silver core radius, spacer shell thickness, a confocal elliptical core/shell cylinder on the property of multiband absorption, and the absorptivity of the structure with one core/four shells coaxial cylinders were explored.