Design of highly absorbing metamaterials for infrared frequencies

Simple designs for polarization independent, metamaterial absorbers at mid-infrared wavelengths and over wide angle of incidence are evaluated computationally. One design consists of an array of circular metallic disks separated from a continuous metallic film by a dielectric film, and shows over 99.9% peak absorbance and a resonant bandwidth of about 0.2 μm wavelengths. The effects of various geometric parameters are analyzed for this metamaterial. Another design consisting of an array of stacked metal-dielectric-metal disks is shown to have an absorbance of over 90% in a comparatively large band of over 1 μm bandwidth, although with a lower peak absorbance of 97%.