The interaction of an atom with an intense laser field provides an important approach to explore the ultrafast electron dynamics and extract the information of the atomic and molecular structures with unprecedented at...The interaction of an atom with an intense laser field provides an important approach to explore the ultrafast electron dynamics and extract the information of the atomic and molecular structures with unprecedented attosecond temporal and angstrom spatial resolution.To well understand the strong field atomic processes,numerous theoretical methods have been developed,including solving the time-dependent Schrodinger equation(TDSE),classical and semiclassical trajectory method,quantum S-matrix theory within the strong-field approximation,etc.Recently,an alternative and complementary quantum approach,called Bohmian trajectory theory,has been successfully used in the strong-field atomic physics and an exciting progress has been achieved in the study of strong-field phenomena.In this paper,we provide an overview of the Bohmian trajectory method and its perspective on two strong field atomic processes,i.e.,atomic and molecular ionization and high-order harmonic generation,respectively.展开更多
We theoretically study the high-order harmonic generation (HHG) in a two-color laser field using the Bohmian mechanics. Our results show that, for tile case of a weak second-color laser field, the simulation of the ...We theoretically study the high-order harmonic generation (HHG) in a two-color laser field using the Bohmian mechanics. Our results show that, for tile 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 Schrodinger 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. Furthermore, 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.展开更多
Using Bohmlan trajectory (151) method, we investigate the dynamic interference in nlgn-orcter narmonlc generauon from diatomic molecular ions. It is demonstrated that the main characteristics of the molecular harmon...Using Bohmlan trajectory (151) method, we investigate the dynamic interference in nlgn-orcter narmonlc generauon from diatomic molecular ions. It is demonstrated that the main characteristics of the molecular harmonic spectrum can be well reproduced by only two BTs which are located at the two ions. This haiapens because these two localized trajectories can receive and store the whole collision information coming from all of the other re-collision trajectories. Therefore, the amplitudes and frequencies of these two trajectories represent the intensity and frequency distribution of the harmonic generation. Moreover, the interference between these two trajectories shows a dip in the harmonic spectrum, which reveals the molecular structure information.展开更多
The duration of a bound electron tunneling through the barrier formed by atomic potential and electrostatic field is calculated by the Bohmian trajectories scheme. The time of the tunneling ionization decreases with t...The duration of a bound electron tunneling through the barrier formed by atomic potential and electrostatic field is calculated by the Bohmian trajectories scheme. The time of the tunneling ionization decreases with the increase of the amplitude of the electrostatic field. By using the information about the position, velocity and force of the Bohmian trajectories, the dynamical process of tunneling through the barrier is investigated.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11922413,11834015,11874392,11804374,11847243,and 11774387)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21010400)
文摘The interaction of an atom with an intense laser field provides an important approach to explore the ultrafast electron dynamics and extract the information of the atomic and molecular structures with unprecedented attosecond temporal and angstrom spatial resolution.To well understand the strong field atomic processes,numerous theoretical methods have been developed,including solving the time-dependent Schrodinger equation(TDSE),classical and semiclassical trajectory method,quantum S-matrix theory within the strong-field approximation,etc.Recently,an alternative and complementary quantum approach,called Bohmian trajectory theory,has been successfully used in the strong-field atomic physics and an exciting progress has been achieved in the study of strong-field phenomena.In this paper,we provide an overview of the Bohmian trajectory method and its perspective on two strong field atomic processes,i.e.,atomic and molecular ionization and high-order harmonic generation,respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11334009,11474321,and 11527807)
文摘We theoretically study the high-order harmonic generation (HHG) in a two-color laser field using the Bohmian mechanics. Our results show that, for tile 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 Schrodinger 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. Furthermore, 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.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB922200)the National Natural Science Foundation of China(Grant Nos.11274141,11034003,11304116,61275128,11247024,and 11274001)the Research Foundation for Basic Research of Jilin Province,China(Grant No.20140101168JC)
文摘Using Bohmlan trajectory (151) method, we investigate the dynamic interference in nlgn-orcter narmonlc generauon from diatomic molecular ions. It is demonstrated that the main characteristics of the molecular harmonic spectrum can be well reproduced by only two BTs which are located at the two ions. This haiapens because these two localized trajectories can receive and store the whole collision information coming from all of the other re-collision trajectories. Therefore, the amplitudes and frequencies of these two trajectories represent the intensity and frequency distribution of the harmonic generation. Moreover, the interference between these two trajectories shows a dip in the harmonic spectrum, which reveals the molecular structure information.
基金Supported by the National Basic Research Program of China under Grant No 2013CB922200the National Natural Science Foundation of China under Grant Nos 11274141,11304116,11274001 and 11247024the Jilin Provincial Research Foundation for Basic Research under Grant No 20140101168JC
文摘The duration of a bound electron tunneling through the barrier formed by atomic potential and electrostatic field is calculated by the Bohmian trajectories scheme. The time of the tunneling ionization decreases with the increase of the amplitude of the electrostatic field. By using the information about the position, velocity and force of the Bohmian trajectories, the dynamical process of tunneling through the barrier is investigated.