Here we discuss the new effects in the light-atom interaction of an atom and two-colour ( ω , 2 ω ) elliptically polarized femtosecond pump beams. We show that the spectrum of atomic response does not include the signal at summary frequency ( ω + 2 ω ) and its harmonics when the frequency components of the pumping field are counter-rotating and the atom is in s -ground state. In the case when the ground state of the atom is p -state ( l = 1), these components vanish in the response spectrum of the longitudinal atomic current. In both cases, the suppression of the summary frequency is accompanied by the suppression of signal at THz frequency.

中文翻译：

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原子介质中双色圆偏振激光场产生的高次谐波频谱

在这里，我们讨论原子和双色椭圆偏振飞秒泵浦光束的光-原子相互作用中的新作用。我们表明，当泵浦场的频率分量反向旋转且原子处于s-基态时，原子响应的光谱不包括总频率（ω+ 2ω）的信号及其谐波。在原子的基态为p-态（l = 1）的情况下，这些成分在纵向原子电流的响应谱中消失。在这两种情况下，总频率的抑制都伴随着对太赫兹频率信号的抑制。