圆偏振激光脉冲附加静电场或太赫兹场时H2+高次谐波产生

本文通过数值求解二维含时薛定谔方程理论的研究了圆偏振激光脉冲(circularly polarized laser pulse, CPLP)作用下H2+的高次谐波产生(high-order harmonic generation, HHG)。通过对比CPLP附加静电场和CPLP附加太赫兹场(terahertz, THz)时的高次谐波发射谱发现，当在CPLP的方向附加静电场时，谐波谱出现双平台结构，且布满调制，通过电子波包概率分布图像发现，电子三次与母核复合，量子轨道之间产生了较严重的干涉。当附加相同强度的THz场时，电子仅两次与母核复合，量子轨道之间的干涉减少，最终得到了86eV到208eV带宽为122eV的连续谱，相比于附加静电场，谐波谱变得连续且平滑，实现了量子轨道调控。最后，利用半经典三步模型、时频分析和电离几率等对谐波发射物理机制进行了深入研究。

High-order harmonic generation of H2+ in a circularly polarized laser pulse combined with a static electric field or with a terahertz field

We investigate high-order harmonic generation (HHG) for the H2+ molecular ion in a circularly polarized laser pulse(CPLP) by solving a two-dimensional time-dependent Schrödinger equation. A comparison is made between a HHG in a CPLP combined with a static electric field and with a terahertz (THz) field. When the CPLP is combined with a static electric field, it is observed that a double-plateau structure appears, and the harmonic spectrum presents large modulation. The electrons recombine with the parent ion three times, the interference of the different quantum paths exists, which will lead to the modulations of HHG. When the CPLP with a THz field, a continuum spectrum can be achieved (86 eV to 208 eV). The electrons recombine with the parent ion twice in the THz field case, which is less than the recombination time of the static electric field case. The HHG process is studied using the semi-classical three-step model, time-frequency analysis and the temporal evolution of the probability density of an electron wave packet.