Thermally controlled electromagnetically induced transparency metamaterial through the near-field coupling of electric and toroidal resonances

Abstract

We investigate a thermally controlled electromagnetically induced transparency terahertz metamaterial through the near-field coupling of electric and toroidal resonances. The fundamental unit consists of a composite design incorporating both metal and vanadium dioxide components aimed at inducing toroidal resonance, along with a pair of metal strips generating electric resonance. Simulation results authenticate the coupling mechanism and illustrate that the envisioned EIT phenomenon can be dynamically adjusted by temperature. In a coupled oscillator model analysis, the control over coupling strength primarily emerges from the fluctuating damping rate of the bright-mode oscillator. Moreover, the displacement of the EIT peak is linked to alterations in the inherent resonant frequency of the bright-mode oscillator. This study not only broadens the potential applications for toroidal terahertz metamaterials but also enhances the range of EIT methodologies available, providing practical approaches for the utilization of terahertz slow-light devices, sensors, and switch devices.