Design of Broadband Metamaterial Absorbers in the Near-Infrared Region

Abstract

A metamaterial absorber with broadband and high absorption based on a metal–dielectric disc–ring structure is proposed. The finite difference time domain (FDTD) method is used to analyze the absorption performance of the absorber. The results show that the absorption of the proposed absorber is more than 90% in the band range from 1500 to 4000 nm with an absorption bandwidth of 2500 nm. The absorber has polarization-insensitive properties due to the high symmetry of the structure. In addition, the absorber has large angle absorption characteristics with average absorptions of 92% and 82% at an incidence angle of 60° in TM and TE modes. The surface plasmon resonance (SPR), localized surface plasmon resonance (LSPR) at the metal interface, and cavity resonance between the circular slits work in synergy to enhance the absorption and broaden the absorption bandwidth. The proposed absorber has a simple structure, easily accessible material, and excellent performance with potential applications in infrared detection, imaging, and other fields.