Rotationally induced population inversion between the B2Σu+ and X2Σg+ states of N2+ exposed to an intense laser pulse
Rotationally induced population inversion between the B2Σu+ and X2Σg+ states of N2+ exposed to an intense laser pulse
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DOI：
10.1103/physreva.101.053412
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发表时间：
2020-05
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
我们研究了转动激发在800 nm强飞秒近红外激光脉冲照射下产生的391 nm相干单向辐射空气激光中的作用。通过引入振动自由度和转动自由度，模拟了在强超短激光脉冲中突然产生的含时布居转移过程，揭示了当光场强度较小时，只有在态的振动基态和振动基态的转动高激发能级之间才能实现布居反转，从而实现了391 nm处的激光，即使电子激发态的总布居相对于电子基态的总布居并不反转。
We investigate the role of the rotational excitation in the coherent and unidirectionalemission ofat 391 nm called air lasing generated whenis irradiated with intense femtosecond near-infrared laser pulses at 800 nm. We simulate the time-dependent population transfer process of, which is assumed to be generated suddenly in an intense ultrashort laser pulse, by including vibrational and rotational degrees of freedom, and reveal that, when the light field intensity is below, the population inversion can be achieved inonly between rotationally highly excited levels in the vibrational ground () state of thestate and those in the vibrational ground () state of thestate, so that the lasing at 391 nm is realized even when the total population in thestate of the electronically excitedstate is not inverted with respect to the total population in thestate of the electronic groundstate.