Steerable Coherent Terahertz Radiation Using Sheet Electron Beams to Excite 2-D Composite Arrays of Sub-Wavelength Holes

Steerable coherent terahertz wave emission is attractive for various applications. Aiming for that, we propose to use a uniformly moving sheet electron beam to drive a 2-D composite array of sub-wavelength holes (SHs). Each SH is an independent resonator in the terahertz region, and a set of SHs with different orientations form a composite radiating unit. Excited by the electron beam, the emissions from all the units in the array constructively interfere in specified directions via the combination of the famous Cherenkov radiation (CR) and Smith–Purcell radiation (SPR) effects, leading to a directional coherent terahertz radiation, which can be real-timely steered by rotating the array. The detailed theoretical analyses of this radiation are performed and verified by simulations. This radiating scheme promises novel types of multi-functional terahertz sources and devices.