Orbital Angular Momentum Generator Based on Super Smith-Purcell Radiation

摘要

An orbital angular momentum (OAM) generator based on free-electron-driven super Smith-Purcell radiation (super-SPR) is proposed in this paper. The super-SPR carrying the OAM mode can be generated at a specific angle through interaction between the periodically bunched electron beam and a helical grating. The working frequency and topological charge of the OAM mode is related to the dispersion relation and the operating voltage of the free electron beam. The OAM mode of the topological charge of 1 can be achieved at 320GHz at the second harmonic. And the field intensity is significantly enhanced compared with the incoherent Smith-Purcell radiation, which finds potential applications in the OAM communications.