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

Authors

Tao Zhao, University of Electronic Science and Technology of China
Min Hu, University of Electronic Science and Technology of China
Zhen Lian, University of Electronic Science and Technology of China
Renbin Zhong, University of Electronic Science and Technology of China
Sen Gong, University of Electronic Science and Technology of China
C Zhang, University of WollongongFollow
Shenggang Liu, University of Electronic Science and Technology of China

RIS ID

129525

Publication Details

Zhao, T., Hu, M., Lian, Z., Zhong, R., Gong, S., Zhang, C. & Liu, S. (2018). Coherent terahertz Smith-Purcell radiation from Dirac semimetals grating with very deep and narrow slits. Applied Physics Express, 11 (8), 082801-1-082801-4.

Abstract

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 of SPP modes, the cavity and ordinary SPP modes, can be excited by fast electrons under different excitation conditions and then diffracted into radiation in specific directions. The radiation intensity is remarkably enhanced when SPPs are excited, and frequencies can be widely tuned by adjusting the parameters of grating and electrons. Our findings could provide a promising way for developing room temperature, coherent, tunable, directional, and intense THz radiation sources.