Broadband Wide-Angle LIWR Perfect Absorber with Double Dielectric Layer

The wide-bandwidth infrared absorbers of metamaterials have a wide range of applications in thermal emission and imaging. But achieving full window coverage and perfect absorbance in the long-wave infrared band remains a challenge. In order to realize this goal, firstly using impedance matching and equivalent circuits designed a Ti/GaAs/Ti structure. This absorber can achieve a mean absorption of more than 93% in the 8 ~ 13 μm range. To further improve the absorbance and bandwidth, a stacked metamaterial bi-dielectric perfect absorber based on Ti/GaAs/Ti is then proposed, which has a mean absorbance of up to 96.59% with polarization independence in the 8 ~ 15 μm band range. It can be seen that the absorption of over 90% (93.8% in TM mode and 91.4% in TE mode) is still maintained as the angle of incidence is increased to 50°. Perfectly absorbed of Broadband is attained through the mixed effect of the coupled PSPR, LSPR, and the intrinsic absorption of the Si3N4.