Sensing the Charged-Particle Beam Position Using the Terahertz Range Diffraction Radiation from Two Dielectric Rods Covered with Graphene

Abstract

This work considers the terahertz (THz) range diffraction radiation (DR) from a modulated beam of particles passing between two identical dielectric circular microwires covered with graphene. The resistive boundary conditions are set on the zero-thickness graphene covers with the electron conductivity determined from the Kubo formalism. Assuming that the beam velocity is fixed, we use the separation of variables in local coordinates and the addition theorems for cylindrical functions and cast the DR problem to a Fredholm second-kind matrix equation. This allows us to compute both near and far-field characteristics with controlled accuracy. The analysis reveals that a shift of the beam trajectory from the central-symmetric position enables the excitation of additional resonances. “Ignition” of these resonances can be considered as a tool for the beam position monitoring with microscale devices.