Active plasmonic switching at mid-infrared wavelengths with graphene ribbon arrays

TL;DR

This paper demonstrates that doping level modulation in graphene ribbon arrays enables significant mid-infrared plasmonic switching, with multi-layer structures outperforming single-layer ones in modulation depth and wavelength shift.

Contribution

It introduces a theoretical and numerical analysis of active plasmonic switching in doped graphene ribbon arrays, highlighting the advantages of multi-layer configurations.

Findings

Four-layer graphene ribbon achieves ~13 dB modulation depth.

Single-layer graphene achieves ~2.8 dB modulation depth.

Resonance wavelength shifts up to 0.94 microns with doping variation.

Abstract

An active plasmonic switch based on single- and few-layer doped graphene ribbon array operating in the mid-infrared spectrum is investigated with theoretical and numerical calculations. It is shown that significant resonance wavelength shifts and modulation depths can be achieved with a slight variation of the doping concentration of the graphene ribbon. The few-layer graphene ribbon array device outperforms the single-layer one in terms of the achievable modulation depth. Our simulations reveal that, by modulating the Fermi-energy level between 0.2 eV and 0.25 eV, a four-layer graphene ribbon array device can achieve a modulation depth and resonance wavelength shift of ~13 dB and 0.94 micron respectively, compared to ~2.8 dB and 1.85 micron for a single-layer device. Additionally, simple fitting models to predict the modulation depth and the resonance wavelength shift are proposed. These prospects pave the way towards ultrafast active graphene-based plasmonic devices for infrared and THz applications.