Studies on Terahertz electronic sources based on asymmetric doubly-corrugated plasmonic waveguide

The extreme strong near field of spoof surface plasmon (SSP) on the corrugated metal surface is attractive to develop powerful and efficient Terahertz (THz) electronic sources. In this paper, a THz electronic source based on the generation of SSP modes on the asymmetric doubly-corrugated waveguide is studied both theoretically and numerically. Dispersion characteristics of SSP modes on the asymmetric structure are derived and presented by a simplified modal expansion method. Besides, THz electronic sources on this asymmetric doubly-corrugated metallic waveguide are modeled and studied by particle-in-cell simulation based on FDTD algorithm. The results reveal that output power decreases slightly with the asymmetry of doubly-corrugated structure. However, output power can be significantly improved by using an acentric electron beam on the given doubly-corrugated metal surfaces. Our studies on the excitation of SSP modes on the asymmetric doubly-corrugated metal surfaces are instructive to develop this kind of THz electronic sources.