Terahertz wave radiation source based on two-section periodical waveguide structures

A terahertz wave radiation source with two-section periodical waveguide structure (PWS) is proposed and analyzed. The first section (section-I) is used to pre-modulate the electron beam, and the second section (section-II) is for terahertz wave generation. By means of theoretical analysis and numerical simulations, we demonstrate that the starting current density of the beam-wave interaction in section-II can be significantly reduced provided the operation frequency is the harmonic of electron beam´s pre-modulation frequency. This kind of source can generate relatively high power terahertz wave radiation only need the moderate beam current density. And it is a promising tabletop and relatively high power terahertz radiation source for real applications.