We derive a simple ionization rate formula for the ground state of a hydrogen atom in the velocity gauge under the conditions:ω〈〈1 a.u.(a.u.is short for atomic unit) and γ〈〈1(ω is the laser frequency and y ...We derive a simple ionization rate formula for the ground state of a hydrogen atom in the velocity gauge under the conditions:ω〈〈1 a.u.(a.u.is short for atomic unit) and γ〈〈1(ω is the laser frequency and y is the Keldysh parameter).Comparisons are made among the different versions of the Keldysh-Faisal-Reiss(KFR) theory.The numerical study shows that with considering the quasi-classical(WKB) Coulomb correction in the final state of the ionized electron,the photoionization rate is enhanced compared with without considering the Coulomb correction,and the Reiss theory with the WKB Coulomb correction gives the correct result in the tunneling regime.Our concise formula of the ionization rate may provide an insight into the ionization mechanism for the ground state of a hydrogen atom.展开更多
This paper proposes a modified strong field approximation model for evaluating nondipole effects on the ionization of an atom in an intense laser field. The photoelectron longitudinal momentum distributions (PLMD) o...This paper proposes a modified strong field approximation model for evaluating nondipole effects on the ionization of an atom in an intense laser field. The photoelectron longitudinal momentum distributions (PLMD) of a hydrogen-like atom exposed to a mid-infrared laser field is calculated. The theoretical results indicate an obvious asymmetry in the PLMD, and an offset of the PLMD peak appears in the opposite direction of the beam propagation due to nondipole effects. The peak offsets of the PLMD increased with the laser intensity, imposed by the initial state of the hydrogen-like atom.展开更多
In this review,we will focus on recent progress on the investigations of nondipole effects in few-electron atoms and molecules interacting with light fields.We first briefly survey several popular theoretical methods ...In this review,we will focus on recent progress on the investigations of nondipole effects in few-electron atoms and molecules interacting with light fields.We first briefly survey several popular theoretical methods and relevant concepts in strong field and attosecond physics beyond the dipole approximation.Physical phenomena stemming from the breakdown of the dipole approximation are then discussed in various topics,including the radiation pressure and photon-momentum transfer,the atomic stabilization,the dynamic interference,and the high-order harmonic generation.Whenever available,the corresponding experimental observations of these nondipole effects are also introduced respectively in each topics.展开更多
We calculate the time-energy distribution(TED)and ionization time distribution(ITD)of photoelectrons emitted by a doubleextreme-ultraviolet(XUV)pulse and a two-color XUV-IR pulse using the Wigner distribution-like fun...We calculate the time-energy distribution(TED)and ionization time distribution(ITD)of photoelectrons emitted by a doubleextreme-ultraviolet(XUV)pulse and a two-color XUV-IR pulse using the Wigner distribution-like function based on the strong field approximation.For a double-XUV pulse,besides two identical broad distributions generated by two XUV pulses,many interference fringes resulting from the interference between electrons generated,respectively,by two pulses appear in the TED.After adding an IR field,the TED intuitively exhibits the effect of the IR field on the electron dynamics.The ITDs during two XUV pulses are no longer the same and show the different changes for the different two-color fields,the origin of which is attributed to the change of the electric field induced by the IR field.Our analysis shows that the emission time of electrons ionized during two XUV pulses mainly depends on the electric field of the combined XUV pulse and IR pulse.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11274149 and 11304185)the Program of Shenyang Key Laboratory of Optoelectronic Materials and Technology,China(Grant No.F12-254-1-00)
文摘We derive a simple ionization rate formula for the ground state of a hydrogen atom in the velocity gauge under the conditions:ω〈〈1 a.u.(a.u.is short for atomic unit) and γ〈〈1(ω is the laser frequency and y is the Keldysh parameter).Comparisons are made among the different versions of the Keldysh-Faisal-Reiss(KFR) theory.The numerical study shows that with considering the quasi-classical(WKB) Coulomb correction in the final state of the ionized electron,the photoionization rate is enhanced compared with without considering the Coulomb correction,and the Reiss theory with the WKB Coulomb correction gives the correct result in the tunneling regime.Our concise formula of the ionization rate may provide an insight into the ionization mechanism for the ground state of a hydrogen atom.
基金Project supported by the National Natural Science Foundation of China(Grant No.11274149)the Program of Shenyang Key Laboratory of Optoelectronic Materials and Technology,China(Grant No.F12-254-1-00)
文摘This paper proposes a modified strong field approximation model for evaluating nondipole effects on the ionization of an atom in an intense laser field. The photoelectron longitudinal momentum distributions (PLMD) of a hydrogen-like atom exposed to a mid-infrared laser field is calculated. The theoretical results indicate an obvious asymmetry in the PLMD, and an offset of the PLMD peak appears in the opposite direction of the beam propagation due to nondipole effects. The peak offsets of the PLMD increased with the laser intensity, imposed by the initial state of the hydrogen-like atom.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11961131008,11725416,and 11574010)the National Key Research and Development Program of China(Grant No.2018YFA0306302)
文摘In this review,we will focus on recent progress on the investigations of nondipole effects in few-electron atoms and molecules interacting with light fields.We first briefly survey several popular theoretical methods and relevant concepts in strong field and attosecond physics beyond the dipole approximation.Physical phenomena stemming from the breakdown of the dipole approximation are then discussed in various topics,including the radiation pressure and photon-momentum transfer,the atomic stabilization,the dynamic interference,and the high-order harmonic generation.Whenever available,the corresponding experimental observations of these nondipole effects are also introduced respectively in each topics.
基金partially supported by the National Key Research and Development Program of China(Nos.2019YFA0307700and 2016YFA0401100)the National Natural Science Foundation of China(NSFC)(Nos.11774361,11775286,11804405,and 12047576)。
文摘We calculate the time-energy distribution(TED)and ionization time distribution(ITD)of photoelectrons emitted by a doubleextreme-ultraviolet(XUV)pulse and a two-color XUV-IR pulse using the Wigner distribution-like function based on the strong field approximation.For a double-XUV pulse,besides two identical broad distributions generated by two XUV pulses,many interference fringes resulting from the interference between electrons generated,respectively,by two pulses appear in the TED.After adding an IR field,the TED intuitively exhibits the effect of the IR field on the electron dynamics.The ITDs during two XUV pulses are no longer the same and show the different changes for the different two-color fields,the origin of which is attributed to the change of the electric field induced by the IR field.Our analysis shows that the emission time of electrons ionized during two XUV pulses mainly depends on the electric field of the combined XUV pulse and IR pulse.