Actively tunable electromagnetically induced transparency in hybrid Dirac-VO₂ metamaterials

In this paper, we present a metamaterial structure of Dirac and vanadium dioxide (VO₂) and investigate its optical properties using the finite-difference time-domain (FDTD) technique. Using the phase transition feature of VO₂, the design can realize active tuning of the plasmon induced transparency (PIT) effect at terahertz frequency, thereby converting from a single PIT to a double-PIT. When VO₂ is in the insulating state, the structure is symmetric to obtain a single-band PIT effect. When VO₂ is in the metallic state, the structure turns asymmetric to realize a dual-band PIT effect. This design provides a reference direction for the design of actively tunable metamaterials. Additionally, it is discovered that the transparent window’s resonant frequency and the Fermi level in this structure have a somewhat linear relationship. In addition, the structure achieves superior refractive index sensitivity in the terahertz band, surpassing 1 THz/RIU. Consequently, the design exhibits encouraging potential for application in refractive index sensors and optical switches.