We present an approach, a Terahertz streaking-assisted photoelectron spectrum (THz SAPS), to achieve direct observations of ultrafast coherence dynamics with timescales beyond the pulse duration. Using a 24 fs probe pulse, the THz SAPS enables us to well visualize Rabi oscillations of 11.76 fs and quantum beats of 2.62 fs between the 5S _1/2 and 5P _3/2 in rubidium atoms. The numerical results show that the THz SAPS can simultaneously achieve high resolution in both frequency and time domains without the limitation of Heisenberg uncertainty of the probe pulse. The long probe pulse promises sufficiently high frequency resolution in photoelectron spectroscopy allowing to observe Autler–Townes splittings, whereas the streaking THz field enhances temporal resolution for not only Rabi oscillations but also quantum beats between the ground and excited states. The THz SAPS demonstrates a potential applicability for observation and manipulation of ultrafast coherence processes in frequency and time domains.

我们提出了一种方法，即太赫兹条纹辅助光电子能谱 (THz SAPS)，以实现对超快相干动力学的直接观察，其时间尺度超过脉冲持续时间。使用 24 fs 探测脉冲，太赫兹 SAPS 使我们能够很好地可视化 11.76 fs 的拉比振荡和 5 S _1/2和 5 P _{3/2之间的 2.62 fs 的量子节拍}在铷原子中。数值结果表明，太赫兹 SAPS 可以同时在频域和时域实现高分辨率，而不受探测脉冲海森堡不确定性的限制。长探测脉冲在光电子能谱中保证了足够高的频率分辨率，从而可以观察到 Autler-Townes 分裂，而条纹 THz 场不仅提高了 Rabi 振荡的时间分辨率，还提高了基态和激发态之间的量子节拍的时间分辨率。太赫兹 SAPS 展示了在频域和时域中观察和操纵超快相干过程的潜在适用性。