Generation of Terahertz Waves Using Ultrashort Electron Beams from a Photocathode Radio‐Frequency Gun Linac

Abstract

SUMMARYUltrashort (picosecond or femtosecond) electron beams are useful for electromagnetic radiation production in the terahertz (THz) range because the inverse of a 1 ps bunch length corresponds to a frequency of 1 THz. The electron beams were generated by a photocathode radio‐frequency (RF) gun linac. Electron beams with an energy of about 4 MeV at the RF gun exit were accelerated to about 30 MeV in a linac. The accelerated electron beams were compressed by a magnetic bunch compressor, resulting in femtosecond pulse width. THz radiation of the order of 0.1 THz based on coherent Cherenkov radiation (CCR) using hollow dielectric tubes and Smith−Purcell radiation (SPR) using a metallic grating or metasurface are described.