8. Xiong Xiao, Ding Wenjun And Wu Lin, “Smith-Purcell Radiation From Drift Electrons In Graphene”, Photonics & Electromagnetics Research Symposium (PIERS2019), Xiamen, China, 17-20 December 2019.
Cherenkov radiation is an electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium at a speed greater than the phase velocity of light in that medium . As one of the forms of Cherenkov radiation, Smith-Purcell radiation is the electromagnetic radiation emitted when energetic electrons move closely parallel to a periodic grating, where the phase velocity of the light has been altered by the periodic grating . Recently, both Cherenkov and Smith-Purcell radiations have been experimentally demonstrated using low-energy electrons of 0.25-1.4 keV  and 1.5-6 keV , respectively. This low speed of free electrons in space (0.01c) is almost reachable by the “quasi-free” highly mobile electrons in graphene .
In this work, we demonstrate the feasibility of Smith-Purcell radiation from highly mobile field-effect electrons in graphene. The effects of electron velocity and number of graphene layers are studied. It shows that the radiation frequency can be tuned by applying a voltage. Additionally, we also design the grating underneath, to further engineer the direction and profile of the radiated beam. This proposal opens up the field of constructing compact solid-state Smith-Purcell sources of light.
A*STAR SERC Young Individual Research Grants (YIRG No. A1784c0020)