Graphene-based plasmonic modulator on a groove-structured metasurface

Abstract

Graphene holds great potential to provide efficient modulation in optoelectronic integrated circuits due to its excellent tunability in conductivity, and several types of graphene-based photonic modulators have already been demonstrated. In this Letter, a plasmonic modulator was proposed based on a groove-structured metasurface covered by a single-layer graphene sheet, in which a transverse electrical-like mode is accommodated. Our design takes advantage of the field enhancement of the plasmonic mode and overcomes the orientation mismatch between the electrical field of the free surface plasmons and the graphene plane. Therefore, this graphene-based plasmonic modulator exhibits a greatly improved modulation depth, compared with the conventional plasmonic ones. Our theoretical results also show that this modulator can work in a broadband with acceptable insertion loss, indicating possible applications in nanophotonic integrations.

Graphene-based hybrid plasmonic waveguide for highly efficient broadband mid-infrared propagation and modulation

“…Consequently, the change of graphene conductivity plays a major role in the proposed waveguide propagation performance tuning. To the best of our knowledge, the attenuation modulation property of this design is superior to the recently reported broadband waveguide modulators, which have a typical attenuation modulation ranging from 0.1 dB/μm to 5.75 dB/μm [25,26,35,36]. By taking into account the natural doping of graphene from the substrate [25,55], we set the graphene chemical potential μ c = 0.1 eV (V g = 0.38 V) as the "OFF" state point, and μ c = 1.0 eV (V g = 31.32 V) as the "ON" state point of the proposed waveguide.…”

“…Although there are some efficient spatial graphene modulators by integrating a composite metamaterial with modulation depth of up to 85% [33] and by incorporating a QCL cavity with modulation depth of up to 100% [34] under normal incidence have been achieved, the attenuation modulation (or modulation depth) of the graphene-based waveguide modulators is still low. Recently, a graphene-based modulator on a groove-structured metasurface has been proposed with an enhanced attenuation modulation of 0.47 dB/μm and a lower mode loss of 0.31 dB/μm [35]. By placing the graphene layers in position with the maximum of the electric field in the waveguide, a modulation depth of 5.75 dB/μm can be achieved [36].…”

Large modulation capacity in graphene-based slot modulators by enhanced hybrid plasmonic effects

“…According to previous plasmonic knowledge 12 , 13 , the surface plasmon is localized and significantly enhanced at the sharp corners of metal. Therefore, the idea here is to introduce the sharp corners of the metal inside the double-slots region.…”

Graphene-Integrated Plasmonics Metasurface for Active Controlling Artificial Second Harmonic Generation

“…where η0 ≈ 377 Ω is the impedance of air, k0 is the wavenumber of electromagnetic field in free space, and dg is the thickness of the graphene layer, which is assumed to be 1 nm in our work. Although an anisotropic model of graphene is more accurate [57,58], it may affect the absorption effect in graphene layer. The isotropic model is efficient for the tunable ability of graphene in the proposed structure.…”