High-order harmonic generation in a two-color strong laser field with Bohmian trajectory theory

• 来源期刊: 中国物理B（英文版）
• 关键词: high-order harmonic generation two-color laser field Bohmian trajectory
• 年，卷（期）: 2018,（7）
• 页码范围: 333-339
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/7/073204

摘要

We theoretically study the high-order harmonic generation (HHG) in a two-color laser field using the Bohmian me-chanics. Our results show that, for the case of a weak second-color laser field, the simulation of the HHG with only one central Bohmian trajectory is in a good agreement with the ab initio time-dependent Schr?dinger equation (TDSE) results. In contrast, with the increase of the amplitude of the second-color laser field, the HHG spectra from the single central Bohmian trajectory deviate from the TDSE results more and more significantly. By analyzing the Bohmian trajectories, we find that the significant deviation is due to the fact that the central Bohmian trajectory leaves the core quickly in the two-color laser field with the breaking of inversion symmetry. Interestingly, we find that another Bohmian trajectory with different initial position, which keeps oscillating around the core, could qualitatively well reproduce the TDSE results. Fur-thermore, we study the HHG spectrum in a two-color laser field with inversion symmetry and find that the HHG spectrum in TDSE can be still well simulated with the central Bohmian trajectory. These results indicate that, similar to the case of one color laser field, the HHG spectra in a two-color laser field can be also reproduced with a single Bohmian trajectory, although the initial position of the trajectory is dependent on the symmetry of the laser field. Our work thus demonstrates that Bohmian trajectory theory can be used as a promising tool in investigating the HHG process in a two-color laser field.