Bandwidth-tunable THz absorber based on diagonally distributed double-sized VO disks.

Terahertz absorbers combined with phase-changing are a class of stealth materials with adjustable absorptance. However, such absorbers still suffer from insufficient absorption bandwidth. We propose a three-layer terahertz (THz) absorber, consisting of an array of diagonally distributed double-sized disks on a silica-coated gold film. We find this structure can generate the superposition of three resonant absorption peaks to broaden the absorption band. The finite element simulation (FES) results show that the absorption bandwidth can be adjusted from 2.63 to 5.04 THz by simply changing the sizes of the disks. In addition, the peak absorptance can be continuously regulated from 9.8% to 96% by varying the conductivity of . Finally, the absorber is polarization-insensitive and has wide-angle absorption. The wide absorption band and adjustable bandwidth of the absorbers have important applications potentially for intelligent stealth materials.