Dual-band infrared metamaterial absorber based on an asymmetric structure

Abstract A wide-angle, azimuthally insensitive, dual-band metamaterial absorber operating in the mid-infrared region is presented, composed of copper and silicon carbide (SiC). The structure consists of a SiC dielectric layer sandwiched between a continuous copper ground plane and a patterned copper layer on top. Numerical simulations reveal two distinct absorption peaks at different mid-infrared wavelengths, which originate from magnetic polariton resonances excited at those wavelengths. The absorber also exhibits good impedance matching with free space, leading to efficient absorption. High absorption is maintained for incident angles θ ranging from 0° to 80° at azimuthal angles φ = 0° and 90° for both TE and TM polarizations. Furthermore, strong absorption is observed for azimuthal angles φ varying from 0° to 180° at a fixed incident angle of θ = 45°, attributed to the excitation of orthogonal magnetic polariton modes within the asymmetric unit cell. Owing to these characteristics, the proposed metamaterial absorber is well suited for mid-infrared spectroscopy and imaging applications.