Confined plasmons in graphene microstructures: Experiments and theory

mon modes in graphene. We show that the long-wavelength plasmon modes in graphene microstructures can be described by an eigenvalue equation. Using perturbation theory, we extend the eigenvalue equation to plasmon supermodes of arrays of interacting graphene microstructures. The results obtained from this method match well the results obtained using a numerical finite-difference time-domain (FDTD) technique. By comparing the measured transmission spectra of interacting plasmon modes in arrays of graphene strips with the theoretical results, we show that the theoretical models quantitatively match the experimental data very well.