High-harmonic terahertz radiation from prebunched electron beam in the tapered grating structure

Based on the mechanism of incoherent diffraction radiation excited by an electron bunch in the waveguide with periodic structure, this paper presents the concept of coherent THz radiation from the high-harmonic component of modulated free-electron beam in a tapered two-asymmetric grating structure. The results show in this mechanism 0.43THz 3-harmonic radiation can be generated with the efficiency 0.5%.