Spoof-surface-plasmons-assisted enhanced terahertz vacuum electronic source

摘要

Spoof surface plasmons (SSP) is the localized collective electron oscillation mode which is propagating along the corrugated metal surface. The extreme strong near field of SSP mode is very attractive to develop novel terahertz (THz) electronic source. In this paper, SSP-assisted enhanced Terahertz vacuum electronic sources on the metallic grating have been studied with the help of particle-in-cell (PIC) simulation at the frequency near 1THz. Besides, in order to improve the output power of this kind of THz electronic source, three different gradient metasurfaces on the metallic grating are proposed and investigated. One method is to increase the lattice periodicity with a constant grating filling-factor, the second is decreasing lattice periodicity but with a constant groove width and the third one is increasing the lattice periodicity with groove width unchanged. For each case, different variation ratio is optimized by PIC simulation and there is a different variation ratio where the output power can be increased compared with the conventional structure by the same electron beam and other optimized conditions. PIC simulation results show that the maximum output power can be increased by 10% compared with the traditional metallic grating. Our studies about the excitation of SSP on the gradient metallic grating are helpful to develop this kind of THz vacuum electronic source.