Dorfman Konstantin E, Wei Pengfei, Liu Jiayun, Li Ruxin
Opt Express. 2019 Mar 4;27(5):7147-7159. doi: 10.1364/OE.27.007147.
Ultrafast pump-high-harmonic-generation-probe spectroscopy aims to provide a unique observation window into electronic dynamics while using the infrared or visible light sources. While it is widely accepted that the role of excited bound states in high-harmonic generation is negligible, its dynamics play a significant role in time-resolved pump-probe measurements. Here we show that the time-resolved pump-high-harmonic-generation-probe measurement may reveal a significant (up to 20%) contribution of the quantum interference in electron ionization and recombination with atomic system, with the initial or the final state being an excited bound state. Interplay of two dephasing mechanisms of electron-ion and electron-atom collisions yields decay and recovery of the time-resolved signal, respectively, signifying the role of the quantum interference involving excited bound states in recovery mode. Our theory, based on the density matrix Liouville space formalism, is supported by experimental measurements in argon gas.
超快泵浦-高次谐波产生-探测光谱旨在利用红外或可见光源，为电子动力学提供一个独特的观测窗口。虽然人们普遍认为激发束缚态在高次谐波产生中的作用可以忽略不计，但其动力学在时间分辨泵浦-探测测量中起着重要作用。在此我们表明，时间分辨泵浦-高次谐波产生-探测测量可能揭示量子干涉对电子与原子系统电离和复合的显著贡献（高达20%），其中初始或终态为激发束缚态。电子-离子和电子-原子碰撞的两种退相机制的相互作用分别产生时间分辨信号的衰减和恢复，这表明量子干涉在恢复模式中涉及激发束缚态的作用。我们基于密度矩阵刘维尔空间形式的理论得到了氩气实验测量的支持。
