Polarization insensitive metamaterial based electromagnetic multiband absorber in the long-wave infrared (LWIR) region

Abstract

In this paper, we propose a design of metamaterials-based polarization insensitive, broadband electromagnetic (EM) wavebands absorber in the long-wave infrared (LWIR) region. The proposed model consists multilayer of gold-magnesium oxide-germanium-gold-germanium layers from the bottom to the top of the structure. The top surface of our proposed metamaterial structure consists of rings and disk-shape resonators. Using the finite element method, the electromagnetic properties of the metamaterials are investigated in terms of reflectance and absorbance. We find that excitation of localized surface plasmon resonance gives rise to highly localized electromagnetic resonance with the structure. Due to the circularly symmetric nature of the ring resonator, the numerical results show that the proposed design of metamaterial has average absorption (above 90 %) from 12.8 μm to 17.8 μm for both transverse electric (TE) and transverse magnetic (TM) polarization over a wide range of incidence angle. Along with this, it can absorb EM waves completely (100 %) at a particular wavelength of 9.1 μm and 17.8 μm. These results show the proposed model configuration may have wide application in energy harvesting and another optoelectronic area.