Active modulation of electromagnetically induced transparency analog in graphene-based microwave metamaterial

Abstract

Metamaterial analogs of electromagnetically induced transparency (EIT) enable a unique route to enhance light-matter interactions without quantum approach, showing remarkable potentials for slow-light devices and highly sensitive sensors. In particular, dynamic control of EIT in metamaterials opens new avenues for optical networks and electromagnetic communications. Here, we experimentally present, for the first time, the active modulation of EIT analog by integrating graphene into a microwave metamaterial. Experimental results demonstrate that the EIT peak can be dynamically controlled under a relatively low bias voltage applied on graphene. A coupled harmonic oscillation model is exploited to analyze the physical mechanism which lies in the active tuning of the damping rate of the dark mode resonator through varying the graphene's sheet resistance. Via variably dampening the dark resonator using graphene, the coupling condition could be electrically modulated and the continuous tuning of the EIT resonance strength is achieved. In addition, the controllable slow-wave propagation is also performed theoretically based on the tunable phase delay of the transmitted waves. This work opens up promising possibilities for slow-wave manipulation with applications in smart and multifunctional devices.