Coherent emission and attosecond transient absorption of Nin strong fields
作者机构：Department of Physics National University of Defense Technology Hunan Key Laboratory of Extreme Matter and Applications National University of Defense Technology
出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学:物理学 力学 天文学(英文版))
年 卷 期：2024年
核心收录：
学科分类：07[理学] 070203[理学-原子与分子物理] 0702[理学-物理学]
基 金：supported by the National Key Research and Development Program of China (Grant No. 2019YFA0307703) the National Natural Science Foundation of China (Grant Nos. 12234020, 11874066, 12274461, and11974426) the Science and Technology Innovation Program of Hunan Province (Grant No. 2022RC1193)
摘 要：The ionic dynamics induced by strong-field ionization are essential to understand the fundamental physics and chemical *** solving the ionization-coupling equation theoretically, we can simultaneously address strong-field ionization and coupling dynamics in ions. By employing the driving pulse at the wavelength of 1580 nm, we show that the B2Σu+state of the strong field ionization created N2+could be populated by polarization effect and five-photon resonance but there is no population inversion between X2Σg+and B2Σu+states for the nitrogen molecular ions aligning along the laser polarization. In addition, both the ultraviolet supercontinuum and the attosecond transient absorption spectroscopy（ATAS） are calculated to illustrate the characteristics of population and coherence. The Stark shift observed from the transient absorption confirms the origin of ultraviolet supercontinuum. Our results show the evolution of the absorption spectral lineshape, varying from Lorentzian to Fano to inverted Lorentzian and back forth and the optical gain is achieved at 394 eV due to the vibrational coherent dynamics. This study offers valuable insights into the strong-field quantum optics of molecular ions.
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