Active Modulation of an All-Dielectric Metasurface Analogue of Electromagnetically Induced Transparency in Terahertz

Abstract

In this work, an analogue of electromagnetically induced transparency (EIT) is excited by a periodic unit consisting of a silicon rectangular bar resonator and a silicon ring resonator in terahertz (THz). The analogue of the EIT effect can be well excited by coupling of the "bright mode" and the "dark mode" supported by the bar and the ring, respectively. Using the semimetallic properties of graphene, active control of the EIT-like effect can be realized by integrating a monolayer graphene into THz metamaterials. By adjusting the Fermi energy of graphene, the resonating electron distribution changes in the dielectric structures, resulting in the varying of the EIT-like effect. The transmission can be modulated from 0.9 to 0.3 with the Fermi energy of graphene placed under the ring resonator mold varying from 0 to 0.6 eV, while a modulation range of 0.9−0.3 corresponds to Fermi energy from 0 to 0.3 eV when graphene is placed under the rectangular bar resonator. Our results may provide potential applications in slow light devices and an ultrafast optical signal.

Graphene-based terahertz bias-driven negative-conductivity metasurface

“…20–23 The conductivity of graphene can be effectively regulated via chemical doping or by applying externally excited light or an external bias voltage, possibly enabling the combination of graphene and metasurfaces. 24–26…”

Plasmon-Induced Transparency for Tunable Atom Trapping in a Chiral Metamaterial Structure

“…Plasmonic metamaterials, whose microstructure units are composed of noble metals (e. g., Au, Ag), have surface plasmon-related properties [6][7][8]. Here, the EIT is usually called plasmon-induced transparency (PIT), while all-dielectric systems generally use high refractive indices and low-loss materials, such as Si, to design the microstructure units [20][21][22]. Metamaterials-based EIT effect has essential applications in optical storage, nanosensing, filtering, and slow light [6][7][8][20][21][22].…”

“…Here, the EIT is usually called plasmon-induced transparency (PIT), while all-dielectric systems generally use high refractive indices and low-loss materials, such as Si, to design the microstructure units [20][21][22]. Metamaterials-based EIT effect has essential applications in optical storage, nanosensing, filtering, and slow light [6][7][8][20][21][22]. Yang et al proposed a high Q-factor (Q≈483) cavity based on the all-dielectric EIT effect [20].…”

Tunable Extraordinary Optical Transmission with Graphene in Terahertz

“…19 Gao et al 20 realized high-contrast, terahertz-wave modulation using gated graphene and based on extraordinary transmission through ring apertures. Wang et al 25 achieved active tuning of the analogue of electromagnetically induced transparency effects by integrating monolayer graphene into all-dielectric metamaterials in THz. Liu et al 26 investigated the tuning ability of the incorporated graphene in metamaterials based on the anapole mode.…”

“…Moreover, according to evolving requirements in applications, there is an ever-growing desire for adjustable EOT. Intriguingly, the unique tuning properties of graphene in the THz band have captured widespread attention. − The Fermi energy of graphene can be modulated conveniently by applying an external voltage, which achieves ultrawideband tunability by controlling electromagnetic fields . Gao et al realized high-contrast, terahertz-wave modulation using gated graphene and based on extraordinary transmission through ring apertures.…”