Abstract

Smith–Purcell radiation (SPR) refers to the far-field, strong, spike radiation generated by the interaction of the evanescent Coulomb field of the moving charged particles and the surrounding medium. In applying SPR for particle detection and nanoscale on-chip light sources, wavelength tunability is desired. Here we report on tunable SPR achieved by moving an electron beam parallel to a two-dimensional (2D) metallic nanodisk array. By in-plane rotating the nanodisk array, the emission spectrum of the SPR splits into two peaks, with the shorter-wavelength peak blueshifted and the longer-wavelength one redshifted by increasing the tuning angle. This effect originates from the fact that the electrons fly effectively over a one-dimensional (1D) quasicrystal projected from the surrounding 2D lattice, and the wavelength of SPR is modulated by quasiperiodic characteristic lengths. The experimental data are in agreement with the simulated ones. We suggest that this tunable radiation provides free-electron-driven tunable multiple photon sources at the nanoscale.

© 2023 Optica Publishing Group

Unidirectional manipulation of Smith–Purcell radiation by phase-gradient metasurfaces

Yadong Xu, Yang Wang, Qingjia Zhou, Lei Gao, and Yangyang Fu
Opt. Lett. 48(15) 4133-4136 (2023)

Coherent and tunable light radiation from nanoscale surface plasmons array via an exotic Smith–Purcell effect

Weihao Liu
Opt. Lett. 40(20) 4579-4582 (2015)

Efficient terahertz and infrared Smith–Purcell radiation from metal-slot metasurfaces

Yanan Song, Jiayuan Du, Ningxiao Jiang, Liu Liu, and Xinhua Hu
Opt. Lett. 43(16) 3858-3861 (2018)

Generation of Airy beams in Smith–Purcell radiation

Liqiao Jing, Dashuang Liao, Jie Tao, Hongsheng Chen, and Zuojia Wang
Opt. Lett. 47(11) 2790-2793 (2022)

THz Smith–Purcell and grating transition radiation from metasurface: experiment and theory

D. Yu. Sergeeva, A. S. Aryshev, A. A. Tishchenko, K. E. Popov, N. Terunuma, and J. Urakawa
Opt. Lett. 46(3) 544-547 (2021)