A tunable stacked metamaterial absorber with wide-to-narrow band switching from terahertz to far-infrared based on BDS and VO₂

To address the limitations of traditional absorbers, which are typically restricted to either broadband or narrowband single-function performance, this work introduces a dual-functional metamaterial stacked absorber using vanadium dioxide (VO₂) and a three-dimensional bulk Dirac semimetal (BDS). The study designs a terahertz (THz) absorber with adjustable absorption modes and a simple structure. This absorber demonstrates a broadband absorption bandwidth of 44.73 THz, achieving an average absorption rate of 97.4%. Additionally, when configured for narrowband performance, it exhibits seven absorption peaks with a maximum sensitivity of 1474 GHz per RIU. The potential applications of this absorber include THz thermal imaging and stealth technology.