A Traveling-Wave Ring Resonator with Bragg Deflectors in a Two-Stage Terahertz Free-Electron Laser

摘要

We propose a scheme of a two-stage terahertz free-electron laser (FEL) based on a Bragg travel- ing-wave ring resonator and parallel ribbon relativistic electron beams. The first beam moves in the field of a planar undulator and generates a pumping wave in the millimeter range. At the second stage, this wave trans- forms into terahertz radiation in the course of intraresonator backscattering on the second parallel electron beam. The ring resonator consists of four Bragg deflectors, each deflecting radiation by 90° in the vicinity of Bragg resonance, thus closing the feedback ring of the low-frequency pumping generator and simultaneously providing effective transfer of the pumping wave to the scattering stage.