Ultra-Broadband Polarization-Independent Terahertz Absorber Based on All-Dielectric GaN Metamaterials

In this article, an ultra-wideband wide-angle absorber based on all dielectric gallium arsenide (GaN) is proposed. The proposed absorber comprises a all dielectric square GaN structure and a GaN substrate. Numerical simulation results demonstrate that the proposed absorber achieves over 90% ultra-wideband absorption in the range of 0.26-1.7 THz, with a relative bandwidth of 146.9%. The ultra-broadband absorption property of the proposed absorber is further validated by an equivalent circuit model, which agrees well with the full-wave numerical simulation results obtained using the finite element method. The simulated electromagnetic field distribution indicates that ultra-wideband absorption primarily originates from the excitation of Fabry-Perot interference modes and electromagnetic resonance. The proposed absorber exhibits wide-angle incidence properties and polarization insensitivity in both transverse electric and transverse magnetic modes. Thus, the proposed GaN ultra-wideband terahertz absorber holds significant potential for applications in fields such as imaging technology and biomedicine.