双色反向旋转圆偏振激光场下氩原子高次谐波的产生

通过二阶分裂算符法数值求解了二维含时薛定谔方程，研究了双色反向旋转圆偏振激光场作用下氩原子的高次谐波的产生.研究表明，双色反向旋转圆偏振激光场的幅值比对高次谐波发射的效率有较大影响，当幅值比为1.4时高次谐波的发射效率最高，并应用时频分析方法、经典三步模型以及利萨茹图形等解释了高次谐波发射的物理机制.研究了不同幅值比情况下谐波场的旋转偏振特性，发现对不同频段的谐波谱的电场进行叠加，谐波场的偏振特性随幅值比的不同而发生变化，但谐波场的旋向性与入射激光脉冲的旋向性相同，不受幅值比变化的影响.

The high-order harmonic generation of Ar atom driven by bichromatic circularly polarized laser fields

The circularly polarized high-order harmonic generation of Ar atom driven by bichromatic circularly polarized laser fields is theoretically investigated by solving a two-dimensional time-dependent Schrödinger equation using the splitting-operator fast-Fourier transform technique. It is found that changing the relative intensity ratio, the harmonic plateau is enhanced, and the polarization properties of the harmonic field are changed. The highest harmonic efficiency is found at the relative intensity ratio, which is consistent with the results in the literature. We also explain the characteristics of harmonic spectrum by using the time-frequency analysis, the semi-classical three step model and Lissajous figures. Furthermore, we superpose the harmonic fields of different frequencies with different relative intensity ratios and find that the rotation of the harmonic field is the same as that of the incident laser pulse. However, the polarization properties of the harmonic field are changed under the different relative intensity ratios. Therefore, the enhancements of the harmonic plateau and the rotation polarization characteristics are regulated by the change of relative intensity ratio.