Tunable bandwidth vanadium dioxide-based terahertz metamaterial absorber

A tunable broadband terahertz metamaterial absorber incorporating vanadium dioxide (VO2) is presented in this study. The device demonstrates adjustable and multifunctional performance within the terahertz (THz) frequency spectrum. In the metallic phase of VO2, the absorber achieves broadband absorption exceeding 90% over the frequency range of 2.89–6.11 THz. Conversely, when VO2 undergoes a phase transition to its insulating state, the device exhibits four distinct narrowband perfect absorption peaks, with absorption rates of 90.6% at 3.96 THz, 98.3% at 4.50 THz, 99.7% at 6.14 THz, and 99.0% at 6.53 THz. By exploiting the contrasting electrical conductivities of VO2 in its metallic and insulating phases, the absorber can be dynamically switched between broadband and multi-band narrowband perfect absorption modes. This tunable absorber design offers substantial potential for applications in electromagnetic stealth technology, pharmaceutical detection, and spectral analysis, thereby providing valuable insights for the development of adaptable terahertz absorption devices.