We study theoretically the action of subcycle unipolar pulses on the rotational dynamics of polar molecules. We show that efficient excitation of molecular rotational resonances by subcycle pump pulses with respect to bipolar single-cycle one is achieved, provided that duration of excitation pulses is much smaller than the rotational period of the molecule. The excitation probability for different rotational levels is analysed in dependence on the parameters of molecules and pump pulses. Remarkably, our analysis revealed the possibility of the almost single level excitation and the formation of the population inversion in the rotational levels excited by unipolar pulses, in spite of the nonresonant interaction and ultrabroad spectrum of subcycle pulses. This approach is entirely different from the traditional resonant excitation techniques with long quasi-monochromatic pulses tuned to the molecular transition. And from the other methods, when multi-color laser pulses or single-c...

中文翻译：

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单极子周期脉冲激发分子旋转能级

我们从理论上研究了亚周期单极性脉冲对极性分子旋转动力学的作用。我们表明，只要激发脉冲的持续时间比分子的旋转周期小得多，就可以通过子周期泵浦脉冲相对于双极单周期单脉冲有效地激发分子旋转共振。根据分子和泵浦脉冲的参数分析不同旋转水平的激发概率。值得注意的是，我们的分析揭示了尽管单周期脉冲具有非共振相互作用和超宽频谱，但单极脉冲激发的旋转能级中几乎是单能级激发并形成种群反转的可能性。这种方法与传统的共振激发技术完全不同，后者将长的准单色脉冲调谐到分子跃迁。从其他方法来看，当使用多色激光脉冲或单色激光时，...