DOI: 10.1063/5.0344312 ISSN: 0003-6951
Free electron radiation based on gradient metasurfaces
Gaoli Xiang, Zhigang Lu, Ping Zhang, Sunchao Huang, Zhanliang Wang, Yuan Zheng, Shaomeng Wang, Yubin GongA free electron radiation mechanism based on gradient metasurfaces (GMs) is proposed in this Letter. Owing to the additional wave vector provided by the GM, surface waves of the electron bunch can be transformed into directional spatial radiated waves according to the generalized Snell's law. Furthermore, the radiation angle can be adjusted by changing the velocity of the electron bunch or the phase gradient of the GM. Simulations in the terahertz (THz) band are carried out and the results agree well with the theoretical predictions. Our proposal here may enable compact and integrable electromagnetic radiation sources, especially for frequencies in the THz band.