少周期激光脉冲附加太赫兹场对高次谐波发射的影响

本文通过数值求解非伯恩奥本海默近似下电子一维核一维的含时薛定谔方程,研究了少周期线偏振激光与氢分子离子相互作用下,太赫兹场的加入对高次谐波的发射影响.我们发现,在短周期线偏振激光脉冲的y方向上附加一个强度较弱的太赫兹场可以有效地扩展谐波的截止位置,并对量子轨道实现调控.通过时频分析、电子波包随时间变化以及半经典三步模型研究了高次谐波发射的物理机制,并对获得的物理现象给出合理的解释.

Influences of circularly polarized laser pulse combined with a terahertz field on the high order harmonic generation

We theoretically investigate the high-order harmonic generation (HHG) from a full one-dimensional (1D) model of H2+ molecule in a few-cycle linearly polarized laser field by using numerical solutions of the non-Born-Oppenheimer time-dependent Schrödinger equation (TDSE). We find that the cut-off of harmonic can be greatly extended and the electronic quantum path can be controlled when a THz field is added. We also investigate emission time of harmonics in terms of the time-frequency analysis, the temporal evolution of the probability density of electron wave packet and the semi-classical three-step model to illustrate the physical mechanism of high-order harmonic generation.