Electron-Beam-Driven Enhanced Terahertz Coherent Smith-Purcell Radiation Within a Cylindrical Quasi-Optical Cavity

In this paper, an electron-beam-driven enhanced terahertz (THz) coherent Smith-Purcell radiation (SPR) from the interaction between cylindrical surface wave and annular electron beam within a cylindrical quasi-optical cavity is presented. The results show that the quasi-optical cavity plays a very important role in the coherent SPR resonance and energy feedback which leads to an enhanced coherent SPR with relatively high efficiency and low current density. Moreover, it is found that the radiated field intensity and field energy of the coherent SPR with the quasi-optical cavity has been improved five times and almost one order of magnitude, respectively, compared with those without the cavity. This system provides an alternative way for high-performance THz sources.