Electromagnetically induced transparency control in terahertz metasurfaces based on bright-bright mode coupling

TL;DR

This paper demonstrates a tunable electromagnetically induced transparency effect in terahertz metasurfaces using bright-bright mode coupling, verified experimentally and theoretically, with potential for active optical control.

Contribution

It introduces a novel terahertz EIT metasurface based on bright-bright mode coupling and demonstrates dynamic tuning via integrated photosensitive silicon pads.

Findings

Successful experimental verification of two-bright mode coupling in terahertz EIT metasurfaces.

Numerical and theoretical analysis confirming the EIT mechanism.

Active control of EIT window achieved through hybrid metasurface with silicon pads.

Abstract

We demonstrate a classical analogue of electromagnetically induced transparency (EIT) in a highly flexible planar terahertz metamaterial (MM) comprised of three-gap split ring resonators. The keys to achieve EIT in this system are the frequency detuning and hybridization processes between two bright modes coexisting in the same unit cell as opposed to bright-dark modes. We present experimental verification of two-bright mode coupling for a terahertz EIT-MM in the context of numerical results and theoretical analysis based on a coupled Lorentz oscillator model. In addition, a hybrid variation of the EIT-MM is proposed and implemented numerically in order to dynamically tune the EIT window by incorporating photosensitive silicon pads in the split gap region of the resonators. As a result, this hybrid MM enables the potential active optical control of a transition from the on-state (EIT mode) to the off-state (dipole mode).