Generation and control of high-order harmonics in a cesium-atom magnetic-resonance system under strong radio-frequency driving
Phys. Rev. A 114, 013123 – Published 27 July, 2026
DOI: https://doi.org/10.1103/j8rl-7th8
Abstract
We report the experimental demonstration of the odd- and even-order harmonics predicted by [Chen et al., Phys. Rev. A 102, 053703 (2020)] and [S. Ashhab, J. R. Johansson, A. M. Zagoskin, and F. Nori, Phys. Rev. A 75, 063414 (2007)]. Using a cesium-atom magnetic-resonance platform under strong periodic driving, we observe a distinct transition in the time-domain signal between armchair- and sawtooth-like plateaus. Analysis of the Fourier amplitude spectrum reveals strict symmetry constraints within the monochromatic field region, where odd- and even-order harmonics can only occur individually. By implementing a bichromatic driving scheme, the selection rules in the case of a monochromatic field are broken, enabling the coexistence of odd- and even-order harmonics. This bichromatic harmonic engineering mechanism provides a physically meaningful means of control for periodically driven quantum systems. Our work establishes an experimental atomic magnetic-resonance platform for revealing symmetry-controlled harmonic engineering in a periodically driven quantum system, providing a generic physical paradigm that is conceptually relevant to bichromatic Floquet-control protocols in other quantum platforms.
