Observation of Rabi dynamics with a short-wavelength free-electron laser

Here we show that femtosecond extreme-ultraviolet pulses from a seeded free-electron laser can drive Rabi dynamics between the ground state and an excited state in helium atoms. S.Nandi et al. Nature, 608, 488 (2022).
The sinusoidal energy transfer between the XUV-FEL coupled states |a⟩ and |b⟩ (black horizontal lines) is associated with sign changes of state amplitudes between adjacent Rabi cycles (+ and −)
The possibility to simultaneously drive and interrogate ultrafast coherent processes using XUV-FEL pulses has been demonstrated. Previous attempts to understand Rabi dynamics at short wavelengths have relied on the strong-field approximation, where the influence of the atomic potential is neglected, leading to an inconsistent  Autler–Townes (AT) doublet when compared with numerical simulations. In contrast, our analytical model includes the full effect of the atomic potential and Rabi dynamics in the two-level subspace, whereas the remaining transitions to and within the complement of the Hilbert space are treated by time-dependent perturbation theory.

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Nandi S, Olofsson E, Bertolino M, Carlström S, Zapata F, Busto D, Callegari C, Di Fraia M, Eng-Johnsson P, Feifel R, Gallician G, Gisselbrecht M, Maclot S, Neoričić L, Peschel J, Plekan O, Prince K C, Squibb R J, Zhong S, Demekhin P V, Meyer M, Miron C, Badano L, Danailov M B, Giannessi L, Manfredda M, Sottocorona F, Zangrando M, Dahlström J M
Nature, Vol. 608, pp. 488-493 (2022)
doi: 10.1038/s41586-022-04948-y
 
Last Updated on Friday, 07 October 2022 12:22