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arXiv · 2007.15723

Orbital angular momentum beam generation using a free-electron laser oscillator

Peifan Liu·Jun Yan·Andrei Afanasev·Stephen V. Benson·Hao Hao·Stepan F. Mikhailov·Victor G. Popov·Ying K. Wu
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Abstract

With wavelength tunability, free-electron lasers (FELs) are well-suited for generating orbital angular momentum (OAM) beams in a wide photon energy range. We report the first experimental demonstration of OAM beam generation using an oscillator FEL. Lasing around 458 nm, we have produced the four lowest orders of coherently mixed OAM beams with good beam quality, excellent stability, and substantial intracavity power. We have also developed a pulsed mode operation of the OAM beam with a highly reproducible temporal structure for a range of modulation frequencies from 1 to 30 Hz. This development can be extended to short wavelengths, for example to x-rays using a future x-ray FEL oscillator. The operation of such an OAM FEL also paves the way for the generation of OAM gamma-ray beams via Compton scattering.

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Peifan Liu, Jun Yan, Andrei Afanasev, Stephen V. Benson, Hao Hao, Stepan F. Mikhailov, Victor G. Popov, Ying K. Wu. 2020-07-30. Orbital angular momentum beam generation using a free-electron laser oscillator. https://doi.org/10.1364/oe.510649

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