Near and Far Field Characteristics of Two in Line Graphene Coated Dielectric Nanowires Excited by Modulated Electron Beam

The work is dedicated to the analysis of the infrared and terahertz range diffraction radiation of a beam of charged particles passing above two graphene-covered dielectric nanowires. As usual within DR studies, we assume fixed electron beam velocity, apply the separation of variables in the local coordinates and the addition theorem for the cylindrical functions to satisfy wave-scattering boundary-value problem. For the graphene cover, we use the quantum-theory Kubo formalism and the resistive-type boundary conditions. As a result, we transform the diffraction radiation problem into a Fredholm second-kind matrix equation for the expansion coefficients of the scattered field. Due to such treatment, the scattering and absorption characteristics and the field patterns can be found with controlled accuracy. In the focus of the study, there are the resonance effects associated with plasmon supermodes of four different classes of symmetry. Our work can be useful in dielectric laser accelerator design.