Orbital angular momentum generator based on super Smith-Purcell radiation

Zhang, Zi-Wen and Du, Chao-Hai and Zhu, Juan-Feng and Li, Fan-Hong and Liu, Pu-Kun and Cross, Adrian W. and Zhang, Liang; (2020) Orbital angular momentum generator based on super Smith-Purcell radiation. In: 2020 13th UK-Europe-China Workshop on Millimetre-Waves and Terahertz Technologies, UCMMT 2020. 2020 13th UK-Europe-China Workshop on Millimetre-Waves and Terahertz Technologies, UCMMT 2020 . Institute of Electrical and Electronics Engineers Inc., CHN. ISBN 9781728190648 (https://doi.org/10.1109/UCMMT49983.2020.9296121)

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Abstract

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.