Ciappina M F, Pérez-Hernández J A, Landsman A S, Zimmermann T, Lewenstein M, Roso L, Krausz F
Max-Planck Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany.
Centro de Láseres Pulsados (CLPU), Parque Científico, E-37008 Villamayor, Salamanca, Spain.
Phys Rev Lett. 2015 Apr 10;114(14):143902. doi: 10.1103/PhysRevLett.114.143902. Epub 2015 Apr 8.
We present a theoretical investigation of carrier-wave Rabi flopping in real atoms by employing numerical simulations of high-order harmonic generation (HHG) in alkali species. Given the short HHG cutoff, related to the low saturation intensity, we concentrate on the features of the third harmonic of sodium (Na) and potassium (K) atoms. For pulse areas of 2π and Na atoms, a characteristic unique peak appears, which, after analyzing the ground state population, we correlate with the conventional Rabi flopping. On the other hand, for larger pulse areas, carrier-wave Rabi flopping occurs, and is associated with a more complex structure in the third harmonic. These characteristics observed in K atoms indicate the breakdown of the area theorem, as was already demonstrated under similar circumstances in narrow band gap semiconductors.
我们通过对碱金属原子中的高次谐波产生（HHG）进行数值模拟，对实际原子中的载波拉比振荡进行了理论研究。鉴于与低饱和强度相关的HHG截止较短，我们专注于钠（Na）和钾（K）原子的三次谐波特征。对于2π脉冲面积的Na原子，出现了一个独特的特征峰，在分析基态布居后，我们将其与传统的拉比振荡相关联。另一方面，对于更大的脉冲面积，会发生载波拉比振荡，并且与三次谐波中更复杂的结构相关。在K原子中观察到的这些特征表明了面积定理的失效，这在窄带隙半导体的类似情况下已经得到了证明。
