Actively Tunable and Polarization-Independent Toroidal Resonance in Hybrid Metal-Vanadium Dioxide Metamaterial

Abstract

Actively tunable and polarization-independent toroidal resonance in hybrid metal-vanadium dioxide metamaterial is proposed and demonstrated numerically in terahertz regime. Simulation results illustrate that a toroidal dipolar resonance is excited by hybrid metal and vanadium dioxide resonator and insensitive with polarization angle of incident plane wave, calculated scattered powers verify the toroidal resonance is strengthened. A novel modulation of resonance strength in proposed toroidal metamaterial is obtained as the phase transition process of vanadium dioxide and contrary to former hybrid metal-vanadium dioxide toroidal metamaterials. The theoretical fitting results reveal that physical mechanism of active modulation in resonance strength can be attributed to the variation of overall damping rate caused by tuning conductivity of vanadium dioxide.