Zhao Z (2025)
Publication Type: Journal article
Publication year: 2025
Book Volume: 134
Article Number: 043804
Issue: 4
Journal Issue: 4
DOI: 10.1103/PhysRevLett.134.043804
The quantum interaction between free electrons and photons is fundamental to free-electron-based light sources and free-electron quantum optics applications. A large coupling between free electrons and photons is generally desired. In this Letter, I obtain the upper bound for the quantum coupling between free electrons and photons. The upper bound has a straightforward expression and can be applied to a broad range of optical materials, especially widely used low-loss photonic materials. The upper bound depends on the optical medium, the free-electron velocity, and the separation between the free electron and the optical medium. With simple structures, the numerically calculated coupling coefficient can reach ∼99% of the upper bound. This study provides simple and practical guidance to reach the strong coupling between free electrons and photons.
APA:
Zhao, Z. (2025). Upper Bound for the Quantum Coupling between Free Electrons and Photons. Physical Review Letters, 134(4). https://doi.org/10.1103/PhysRevLett.134.043804
MLA:
Zhao, Zhexin. "Upper Bound for the Quantum Coupling between Free Electrons and Photons." Physical Review Letters 134.4 (2025).
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