Thz Smith Purcell And Grating Transition Radiation From Metasurface: Experiment And Theory

We report the results of experimental and theoretical studies of monochromatic coherent terahertz radiation generated by a short relativistic electron bunch interacting with a metasurface. The metasurface consists of subwavelength metal elements arranged on a dielectric substrate. The constructed theory explains the experimental spectra of Smith-Purcell radiation and grating transition radiation with wry high precision. The orientational distribution of transition radiation shows a fine structure, which, as we suppose, may be due to contribution of coupling between the metasurface's elements. (C) 2021 Optical Society of America