Mi Kang, Cao Wei, Xu Huiyao, Zhang Qingbin, Lu Peixiang
Opt Express. 2021 Jan 18;29(2):2798-2808. doi: 10.1364/OE.413829.
Ultrafast wave-mixing spectroscopies involving extreme ultraviolet (EUV) attosecond pulses provide unprecedented insight into electronic dynamics. Here, we proposed a versatile lifetime-detection method for doubly excited states with odd or even parities by mixing an attosecond EUV pulse with two few-cycle near infrared (NIR) pulses in atomic helium under a noncollinear geometry. By properly choosing the time order of the pulse sequence, the spatially resolved nonlinear signals carry significant information of the decaying dynamics of excited states, which can be utilized to retrieve the lifetimes of states with different parities in a single measurement. The validity and robustness of the method has been verified by numerical simulations based on a few-level model of helium including the spatial distribution of atoms. The accuracy of the lifetime measurement method is better than a few hundred attoseconds. It provides a powerful tool for probing decaying dynamics of the electronic wave packet with superb resolution.
涉及极紫外（EUV）阿秒脉冲的超快波混频光谱技术为电子动力学提供了前所未有的见解。在此，我们提出了一种通用的寿命检测方法，用于在非共线几何结构下，通过将阿秒EUV脉冲与两个少周期近红外（NIR）脉冲在氦原子中混合，来检测具有奇宇称或偶宇称的双激发态。通过适当选择脉冲序列的时间顺序，空间分辨的非线性信号携带了激发态衰减动力学的重要信息，这些信息可用于在单次测量中获取不同宇称态的寿命。该方法的有效性和稳健性已通过基于包含原子空间分布的氦原子多能级模型的数值模拟得到验证。寿命测量方法的精度优于几百阿秒。它为以超高分辨率探测电子波包的衰减动力学提供了一个强大的工具。
