Theoretical and Experimental Demonstrations of a Dual-Band Metamaterial Absorber at Mid-Infrared

Abstract

We present the design, fabrication, and physical interpretation of an infrared dual-band metamaterial absorber. The unit cell of the metamaterial absorber consists of a cross resonator ringed by four split-ring resonators spaced a distance above a gold ground plane with a dielectric layer of SiO 2 . The absorber shows two absorption peaks of 90.3% and 88.4% at 4.17 µm and 4.86 µm, respectively. The multireflection interference theory is applied to explain the absorption mechanism with the gold ground plane described by Drude model, and the theoretical calculation agrees well with the simulations and experiments. In addition, the designed absorber is insensitive to incident angle and polarization direction in a broad range, which are highly favorable features in practical applications.

Inverted nanotaper-based Ag film for optical absorption and SERS applications

“…Metamaterials based on plasmonic elements are particularly efficient as absorbing media, because both the electrical and the magnetic properties of a metamaterial can be tuned by structured design [14][15][16][17]. Recent theoretical modeling results also predict different designs with high light absorption of metamaterials in a controllable wavelength range, yet usually under infrared or microwave regimes [6,18,19]. Therefore, to achieve a strong and broad-band light absorption, it will be an efficient way to combine plasmonic resonances based on different metallic elements in a fashion that ultimately enhances the total light absorption.…”