Highly polarization and wide-angle insensitive metamaterial absorber for terahertz applications

Metamaterial absorbers, due to their potential applications in the field of photonics, are vastly studied in the last decade. Herein, we present a novel design of a resonant metamaterial absorber in the terahertz (THz) region based on numerical simulations. This perfect THz absorber, due to its symmetry, is highly independent on the polarization state of an incident plane wave. Moreover, the absorber is insensitive to a wide range of incident angle from 0 to 70°. The absorbance approaches unity at a resonance frequency of 3.74 THz. The absorber shows remarkable results even at the two extreme incident angles, e.g. a minimum absorbance value of ∼80% was recorded at an incident angle of 70°. With this promising performance, the proposed THz absorber can serve as a possible sensing device for transparent analytes adsorbed on it. For this structure, aluminum and TiO2 are used. Both materials are commonly available for manufacturing photonic devices.