Effects of ionization timing for off-resonant population transfer by postionization excitation in N2+
Effects of ionization timing for off-resonant population transfer by postionization excitation in N2+
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DOI：
10.1103/physreva.106.063109
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发表时间：
2022-12
影响因子：
2.9
通讯作者：
Youyuan Zhang;E. Lötstedt;K. Yamanouchi
中科院分区：
文献类型：
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作者：
Youyuan Zhang;E. Lötstedt;K. Yamanouchi
我们使用突然开启模型，通过明确地包括整个激光脉冲中的电离定时效应，研究了在超短脉冲强激光场中创建的三种低位电子态之间的位置化粒子转移过程。通过采用包含电子、振动和旋转自由度的罗振动模型，我们揭示了当电离发生在激光场强度时间形状的中心峰值附近时，在R-和P分支的特定旋转量子数范围内可以实现态与态之间的粒子数反转。基于准稳态Floquet理论，我们检验了上Floquet态最终布居数与激光场强度的依赖性，结果表明只要激光场强度小于0，布居转移就可以通过电离时刻的电离来解释，而当场强变大时，需要考虑在激光脉冲的整个范围内发生的电离过程。
We investigate postionization population transfer processes among the three low-lying electronic states—,, and—ofcreated in an ultrashort-pulsed intense laser field using a sudden turn-on model by explicitly including the ionization timing effect throughout the entire laser pulse. By adopting the rovibronic model in which the electronic, vibrational, and rotational degrees of freedom ofare included, we have revealed that the population inversion between thestate andstate can be realized in the specific rotational quantum number ranges in the R- and P branches when ionization occurs around the central peak of the temporal shape of the laser field intensity. Based on the quasistationary Floquet theory, we have examined the laser field intensity dependence of the final population in the upper Floquet state, corresponding to thestate of, and revealed that the population transfer can be interpreted by the ionization at the ionization timing ofas long as the laser field intensity is less than, while the ionization processes occurring in the entire range of the laser pulse need to be taken into account when the field intensity becomes larger.