Coherent terahertz Smith–Purcell radiation from Dirac semimetals grating with very deep and narrow slits

• DOI: 10.7567/apex.11.082801
• Publication Date: 2018-07-03T09:33:22Z
• Authors: Tao Zhao; Min Hu; Zhen Lian; Renbin Zhong; Sen Gong; Chao Zhang; Shenggang Liu
• Keywords: Engineering; 0103 physical sciences; Science and Technology Studies; 01 natural sciences

We demonstrate a physical mechanism of multicolor coherent terahertz (THz) Smith–Purcell radiation from surface plasmon polaritons (SPPs). In Dirac semimetals gratings with very deep and narrow slits, two types SPP modes, the cavity ordinary can be excited by fast electrons under different excitation conditions then diffracted into in specific directions. The intensity is remarkably enhanced when SPPs are excited, frequencies widely tuned adjusting parameters grating electrons. Our findings could provide promising way for developing room temperature, coherent, tunable, directional, intense THz sources.