Observation of a transition in the dynamics of strong-field atomic excitation

Autor: Shilin Hu, Linqiang Hua, Zheng Shu, YanLan Wang, ZhiLei Xiao, Meng Zhao, Cheng Gong, Jing Chen, MingZheng Wei, SongPo Xu, XuanYang Lai, RenPing Sun, Yu Zhou, Mingqing Liu, XiaoJun Liu, Wei Quan
Rok vydání: 2020
Předmět:
Zdroj: Physical Review A. 102
ISSN: 2469-9934
2469-9926
Popis: The consensus on the mechanism of atomic excitation in an intense laser field has not been reached so far because the proposed mechanisms may dominate in different regimes. In this paper, we show a clear transition of the underlying physical mechanism of strong-field atomic excitation from multiphoton resonance to coherent recapture by investigating the intensity dependence of the yields of neutral excited atoms $({\mathrm{Ar}}^{*})$ and singly charged ions $({\mathrm{Ar}}^{+})$ of argon experimentally and theoretically. Our results indicate that, for 400 nm, the multiphoton resonance mechanism plays a significant role at low intensity and coherent recapture mechanism becomes important at high intensity. While for 800 nm, distinctive out-of-phase oscillations of ${\mathrm{Ar}}^{*}$ and ${\mathrm{Ar}}^{+}$ yields are identified, implying that coherent recapture mechanism dominates. Our work provides a more comprehensive understanding of the atomic excitation mechanism in an intense laser field.
Databáze: OpenAIRE