Observing the ultrafast buildup of a Fano resonance in the time domain
Observing the ultrafast buildup of a Fano resonance in the time domain
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DOI：
10.1126/science.aah6972
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发表时间：
2016-11-11
期刊：
影响因子：
56.9
通讯作者：
Pfeifer, T.
中科院分区：
文献类型：
--
作者：
Kaldun, A.;Blaettermann, A.;Pfeifer, T.
尽管在过去的十年里，吸收光谱中非对称Fano线形随时间的增加引起了极大的理论兴趣，但对这些预测的实验验证一直难以捉摸。本文报道了用强激光场阻断关联双电子激发态的自电离过程，在氦的原型系统中出现Fano共振的实验观察。在激发和终止共振之间的可调时间门允许我们在时间上跟踪Fano线形的形成。与从头计算的一致性验证了我们的实验时间门控技术，用于解决更广泛的主题，如电子关联的出现，电子-核间耦合的开始，以及准粒子的形成。
Although the time-dependent buildup of asymmetric Fano line shapes in absorption spectra has been of great theoretical interest in the past decade, experimental verification of the predictions has been elusive. Here, we report the experimental observation of the emergence of a Fano resonance in the prototype system of helium by interrupting the autoionization process of a correlated two-electron excited state with a strong laser field. The tunable temporal gate between excitation and termination of the resonance allows us to follow the formation of a Fano line shape in time. The agreement with ab initio calculations validates our experimental time-gating technique for addressing an even broader range of topics, such as the emergence of electron correlation, the onset of electron-internuclear coupling, and quasi-particle formation.