Terahertz absorber based on vanadium dioxide with high sensitivity and switching capability between ultra-wideband and ultra-narrowband

materials, and the absorption is more than 99% across 3.64-6.96 THz, and it has excellent characteristics such as robustness. Ultra-narrowband perfect absorption has a quality factor greater than 2200 due mainly to the implementation of symmetrically protected BIC with a sensing sensitivity of 2.575 THz per RIU. Therefore, this research could be widely used in the fields of integrated optical circuits, optoelectronic sensing and perceptual modulation of energy, as well as providing additional design ideas for the design of terahertz multifunctional devices.