Modeling the excitation of graphene plasmons in periodic grids of graphene ribbons: An analytical approach

Abstract

We study electromagnetic scattering and subsequent plasmonic excitations in periodic grids of graphene ribbons. To address this problem, we develop an analytical method to describe the plasmon-assisted absorption of electromagnetic radiation by a periodic structure of graphene ribbons forming a diffraction grating for THz and mid-IR light. The major advantage of this method lies in its ability to accurately describe the excitation of graphene surface plasmons (GSPs) in one-dimensional (1D) graphene gratings without the use of both time-consuming, and computationally demanding full-wave numerical simulations. We thus provide analytical expressions for the reflectance, transmittance, and plasmon-enhanced absorbance spectra, which can be readily evaluated using any personal computer with little to no programming. We also introduce a semianalytical method to benchmark our previous results and further compare the theoretical data with spectra taken from experiments, for which we observe a very good agreement. These theoretical tools may therefore be applied to design new experiments and cutting-edge nanophotonic devices based on graphene plasmonics.

Impact of Graphene on the Polarizability of a Neighbour Nanoparticle: A Dyadic Green’s Function Study

“…However, the effect of the renormalization of the polarizability is greater for the half-filled case. This is because in this regime the plasmonic resonance has the maximum intensity [16,62] Finally, we have verified that when w → L, we recover the results of a continuous graphene sheet. …”

“…Here, the summation in Λ(ω) is delicate due to the oscillatory nature of the Bessel function (see [62]). For simplicity of the calculation, we approximate β j,n =0 by β j,n =0 ≈…”

“…Instrumental to the calculation of the effective conductivity is the knowledge of the reflection and transmission Fresnel coefficients. These coefficients were computed in approximated analytical form in [62] and we give here only the final results:…”

Probing nonlocal effects in metals with graphene plasmons

“…On top of the SiO 2 , we further consider a semi-infinite layer of silicon (Si) described by an isotropic dielectric constant of ε Si = 11.66 [53]. Our theoretical calculations for the grating system follow from the considerations outlined in the previous sections and they are based on a Fourier modal expansion of the electromagnetic fields described elsewhere [3,38]. To be self-contained, we provide the mathematical details in Appendix B.…”

“…Therefore adjusting the grating period can be used to tune the graphene plasmons' frequency to the desired spectral range. Either graphene itself [38] or a grating may be patterned [39]. When graphene is placed in the vicinity of a metallic surface, e.g., as illustrated in Fig.…”