Electron Masers Based on Selective Excitation of Talbot-Type Supermodes in Oversized Cavities

摘要

A natural problem arising in the case of realization of a electron maser operating in the terahertz frequency range is the use of oversized microwave system (with characteristic sized significantly exceeding the operating wavelength). In this situation, it is difficult to provide selective excitation of a definite operating transverse mode. We propose to give up working on a fixed transverse mode, and to use excitation of a supermode formed by a fixed set of several transverse modes of an oversized waveguide. The use of the Talbot effect is proposed to create oversized microwave systems that provide high Q-factors for operating supermode. As an example, in this work we describe our simulations for a 2 THz Free-Electron Maser fed by a high-current relativistic electron beam. In addition, we discuss possibilities for using this approach in THz gyrotrons.