Bandwidth-tunable THz absorber based on diagonally distributed double-sized VO2 disks

摘要

Terahertz absorbers combined with phase-changing VO2 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-sizedVO(2) 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 VO2 disks. In addition, the peak absorptance can be continuously regulated from 9.8% to 96% by varying the conductivity of VO2. Finally, the absorber is polarizationinsensitive and has wide-angle absorption. The wide absorption band and adjustable bandwidth of the absorbers have important applications potentially for intelligent stealth materials. (C) 2021 Optical Society of America