We report on the observation of time-resolved quantum beats in the helium fluorescence from the transition 1s3p → 1s2s, where the initial state is excited by XUV free electron laser radiation. The quantum beats originate from the Zeeman splitting of the magnetic substates due to an external magnetic field. We perform a systematic study of this effect and discuss the possibilities of studying this phenomenon in the XUV and x-ray regime.

中文翻译：

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XUV辐射共振激发的氦荧光中的时间分辨量子拍

我们报告了从1 s 3 p →1 s 2 s跃迁中氦荧光中时间分辨的量子跳变的观察结果，其中初始状态由XUV自由电子激光辐射激发。量子节拍源自外部磁场导致的磁性亚态的塞曼分裂。我们对此效果进行了系统的研究，并讨论了在XUV和X射线研究中研究此现象的可能性。