Ultrabroadband Terahertz Absorption by Uniaxial Anisotropic Nanowire Metamaterials

Three-dimensional structure terahertz metamaterial absorbers with the properties of ultrabroadband and polarization-insensitive absorption were proposed. Different from the recent designs of the multilayer horizontal configurations, our design consists of the uniaxial anisotropic gold nanowire arrays that are filled in the frustum pyramid dielectric medium. The principle for the ultrabroadband absorption originates from the overlapping of the different but very closely positioned electromagnetic resonances. Each resonance frequency follows the equation of the odd multiple of the quarter wavelengths, which can be flexibly controlled by varying the height of the corresponding gold nanowires. In addition to the great prospect for the potential applications in terahertz, our design could also be easily extended to the other frequency regimes for a host of applications such as electromagnetic stealth, infrared detection, imaging, and solar cell.