Angle-controlled Simth-Purcell Radiation Excited by Free Electron Beam

When an electron beam passes through the surface of a periodic grating, electromagnetic radiation is generated, and this radiation is referred to as Smith-Purcell radiation. The main methods for modulating Smith-Purcell radiation are changing the grating period and the electron beam voltage. In this study, it is proposed that the Smith-Purcell radiation frequency can be controlled by changing the observation angle, and the experimental observation frequency is consistent with the theory. This has important application significance for the development of free electron radiation sources around Smith-Purcell radiation.