Multicolor Terahertz Frequency Mixer Using Multibunching of Free-Electron Beams

Abstract

Terahertz electromagnetic waves have applications in fields as diverse as biological imaging, materials science, and astrophysics. However, the development of compact, high-power, broadly tunable terahertz sources is challenging. The authors propose a frequency mixer that uses a free-electron beam to drive two cascaded gratings, producing multicolor coherent terahertz radiation via the superradiant Smith-Purcell effect. This device can simultaneously generate several terahertz emissions of high average power, and its frequency can be tuned from 0.8 to 1.8 THz, offering a compact, efficient terahertz source.