Multifunctional terahertz metamaterials device based on a dual-tunable structure incorporating graphene and vanadium oxide

This paper presents a multifunctional terahertz device based on a dual-tunable structure incorporating graphene and vanadium oxide (VO₂). This device enables the switching between narrowband perfect absorption and ultra-broadband performance through the phase transition characteristics of VO₂ and the adjustment of graphene Fermi level. Simulation results demonstrate that when VO₂ is in its metallic state, the THz device exhibits ultra-broadband absorption, achieving a high absorption rate exceeding 0.9 within the frequency range of 2.9-7.67 THz. Conversely, when VO₂ is in its insulating state, the THz device displays perfect absorption peaks at 2.8 and 8.41 THz. In the broadband mode, the absorption band can be broadened to an ultra-broadband range by adjusting the Fermi level of graphene. Furthermore, the structural parameters of terahertz devices, as well as the incident and polarization angles of electromagnetic waves, were investigated. The results demonstrated that the terahertz devices exhibit a certain degree of manufacturing tolerance, stability against variations in incident angles, and favorable polarization insensitivity. Overall, this design holds promising application prospects in fields such as terahertz absorption, refractive index sensing, and terahertz detection.