Uniform Dielectric Cylinder with a Graphene Coating as a Lens

We investigated the focusing effects arising in the diffraction of H-polarized plane wave by a uniform dielectric cylinder with a graphene coating. The analytical solution of the wave-scattering problem is based on the Maxwell equations and the resistive boundary conditions on the zero-thickness graphene cover where the graphene electron conductivity was determined from the Kubo formalism. We use the spectra of normalized cross-sections: scattering and the absorption for finding the frequencies of plasmon resonance in graphene layer. Spatial distribution was computed of the field amplitude in the absorption maxima. Computations were performed out in the wide range of cylinder radius and the wavelength of incident radiation. We demonstrate that the field focusing at the rear surface of the cylinder takes place when the surface plasmon resonance occurs in the structure; the resonance frequencies of different plasmon modes fall into a wide band. An optimal value of the cylinder radius and the frequency of the incident wave were found corresponding to the highest focusing effect.