Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Physics Conference Series

Manipulating quantum interferences in laser dressed-helium by the transferred momentum between the electron projectile and helium target

Hicham Agueny, A. Makhoute, Alain Dubois

Published Jul 1, 2017• 0 citations
Publisher

Abstract

We present theoretical study of energetic electron-impact excitation of "six-level helium atom" embedded in a laser field. During the scattering process, the combined interactions lead to a change in the kinetic energy and the angular distribution of the scattered electron. The latter contains all information about the combined interactions. The analysis of the angular distribution reveals the emergence of a peak profile. This is will be discussed in terms of quantum-path interferences in bound-bound electronic transitions. Furthermore, the sensitivity of the phenomenon to the collision dynamics will also be discussed.

DOI
10.1088/1742-6596/875/6/052034

Related papers

Monoenergetic electron-beam stimulated light-dressing-induced resonance in a helium atom

Hicham Agueny, A. Makhoute

Abstract We present a theoretical study of energetic electron-beam excitation of ‘six-level helium atom’ embedded in a laser field. The angular distribution of the scattered electron-beam, which contains all information about the combined interactions, is analyzed and exhibits a resonant peak in the vicinity of the 1 sns – 1 snp ( n = 2, 3) transitions. Here, we show that this resonant feature can be stimulated by means of the transferred momentum between the collision partners during the scattering process. By manipulating the latter parameter, one can enhance the resonant peak or lead to its attenuation and even to its cancellation. Our findings are supported by additional calculations based on the time-dependent perturbation theory, where a spurious divergence is expected at a resonant region.

Journal of Physics B Atomic Molecular and Optical Physics•Nov 14, 2017•2 citations

Dynamic-Stark-effect-induced coherent mixture of virtual paths in laser-dressed helium: energetic electron impact excitation

Hicham Agueny, A. Makhoute, Alain Dubois

Abstract We theoretically investigate quantum virtual path interference caused by the dynamic Stark effect in bound–bound electronic transitions. The effect is studied in an intermediate resonant region and in connection with the energetic electron impact excitation of a helium atom embedded in a weak low-frequency laser field. The process under investigation is dealt with via a Born–Floquet approach. Numerical calculations show a resonant feature in laser-assisted cross sections. The latter is found to be sensitive to the intensity of the laser field dressing. We show that this feature is a signature of quantum beats which result from the coherent mixture of different quantum virtual pathways, and that excitation may follow in order to end up with a common final channel. This mixture arises from the dynamic Stark effect, which produces a set of avoided crossings in laser-dressed states. The effect allows one to coherently control quantum virtual path interference by varying the intensity of the laser field dressing. Our findings suggest that the combination of an energetic electron and a weak laser field is a useful tool for the coherent control of nonadiabatic transitions in an intermediate resonant region.

Journal of Physics B Atomic Molecular and Optical Physics•Apr 13, 2017•4 citations

Electron-impact excitation of atoms in the presence of a nearly resonant laser field

P. Francken, C. J. Joachain

We have studied the electron-impact excitation of an atom, in the presence of a laser field whose photon energy is tuned close to the energy difference between two excited final states. Both the laser-projectile and the laser-target interactions are treated nonperturbatively, while the electron-atom interaction is treated within the first Born approximation. As an application, we have analyzed the resonant laser-assisted excitation of the ${2}^{1}$S and ${2}^{1}$P states of helium. The agreement between the present nonperturbative results and previous perturbative ones is excellent, except for very small detunings. The present nonperturbative treatment also shows that the results given by perturbation theory on both sides of the resonance, when plotted as a function of the laser frequency, correspond to the excitation of different Floquet pseudostates. This is related to the presence of avoided crossings in the diagram of the Floquet pseudoenergies, as a function of the laser frequency.

Physical Review A•Apr 1, 1990•22 citations

Free-free experiments: dressed-atom effects during inelastic electron scattering

Nicholas L S Martin, B N Kim, C.M. Weaver +1 more

Synopsis Experiments and theory will be presented for the emission/absorption of 1.17 eV photons by electrons during the electron-impact excitation of a helium target in a laser field.

Journal of Physics Conference Series•Jan 1, 2020•0 citations

Quantum interference in attosecond transient absorption of laser-dressed helium atoms

Shaohao Chen, Mengxi Wu, Mette B. Gaarde +1 more

We calculate the transient absorption of an isolated attosecond pulse (IAP) by helium atoms subject to a delayed infrared (IR) laser pulse. With the central frequency of the broad attosecond spectrum near the ionization threshold, the absorption spectrum is strongly modulated at the sub-IR-cycle level. Given that the absorption spectrum results from a time-integrated measurement, we investigate the extent to which the delay dependence of the absorption yields information about the attosecond dynamics of the atom-field energy exchange. We find two configurations in which this is possible. The first involves multiphoton transitions between bound states that result in interference between different excitation pathways. The second involves the modification of the bound state absorption lines by the IR field, which we find can result in a subcycle time dependence only when ionization limits the duration of the strong-field interaction.

arXiv:1301.0771•Physical Review A•Mar 8, 2013•92 citations

Combining laser and electron interactions – current experiments and future possibilities in excitation and ionization studies

Andrew James Murray

In this brief review a number of different experimental techniques that combine the advantages of laser and electron interactions with atoms and molecules will be described. These processes range from super-elastic electron scattering from laser excited atoms so as to ascertain the electron collision parameters over all scattering geometries, through new electron interactions with laser cooled and trapped atoms, to the process of electron impact ionization of laser-aligned targets. Examples from work carried out in Manchester are given, and new types of measurements that may be possible in the future are described. © 2010 IOP Publishing Ltd.

Journal of Physics Conference Series•Feb 1, 2010•2 citations
We present theoretical study of energetic electron-impact excitation of "six-level helium atom" embedded in a laser field. During the scattering process, the combined interactions lead to a change in the kinetic energy and the angular distribution of the scattered electron. The latter contains all information about the combined interactions. The analysis of the angular distribution reveals the emergence of a peak profile. This is will be discussed in terms of quantum-path interferences in bound-bound electronic transitions. Furthermore, the sensitivity of the phenomenon to the collision dynamics will also be discussed.
Abstract We present a theoretical study of energetic electron-beam excitation of ‘six-level helium atom’ embedded in a laser field. The angular distribution of the scattered electron-beam, which contains all information about the combined interactions, is analyzed and exhibits a resonant peak in the vicinity of the 1 sns – 1 snp ( n = 2, 3) transitions. Here, we show that this resonant feature can be stimulated by means of the transferred momentum between the collision partners during the scattering process. By manipulating the latter parameter, one can enhance the resonant peak or lead to its attenuation and even to its cancellation. Our findings are supported by additional calculations based on the time-dependent perturbation theory, where a spurious divergence is expected at a resonant region.
Abstract We theoretically investigate quantum virtual path interference caused by the dynamic Stark effect in bound–bound electronic transitions. The effect is studied in an intermediate resonant region and in connection with the energetic electron impact excitation of a helium atom embedded in a weak low-frequency laser field. The process under investigation is dealt with via a Born–Floquet approach. Numerical calculations show a resonant feature in laser-assisted cross sections. The latter is found to be sensitive to the intensity of the laser field dressing. We show that this feature is a signature of quantum beats which result from the coherent mixture of different quantum virtual pathways, and that excitation may follow in order to end up with a common final channel. This mixture arises from the dynamic Stark effect, which produces a set of avoided crossings in laser-dressed states. The effect allows one to coherently control quantum virtual path interference by varying the intensity of the laser field dressing. Our findings suggest that the combination of an energetic electron and a weak laser field is a useful tool for the coherent control of nonadiabatic transitions in an intermediate resonant region.
We have studied the electron-impact excitation of an atom, in the presence of a laser field whose photon energy is tuned close to the energy difference between two excited final states. Both the laser-projectile and the laser-target interactions are treated nonperturbatively, while the electron-atom interaction is treated within the first Born approximation. As an application, we have analyzed the resonant laser-assisted excitation of the 21{2}^{1}21S and 21{2}^{1}21P states of helium. The agreement between the present nonperturbative results and previous perturbative ones is excellent, except for very small detunings. The present nonperturbative treatment also shows that the results given by perturbation theory on both sides of the resonance, when plotted as a function of the laser frequency, correspond to the excitation of different Floquet pseudostates. This is related to the presence of avoided crossings in the diagram of the Floquet pseudoenergies, as a function of the laser frequency.
We calculate the transient absorption of an isolated attosecond pulse (IAP) by helium atoms subject to a delayed infrared (IR) laser pulse. With the central frequency of the broad attosecond spectrum near the ionization threshold, the absorption spectrum is strongly modulated at the sub-IR-cycle level. Given that the absorption spectrum results from a time-integrated measurement, we investigate the extent to which the delay dependence of the absorption yields information about the attosecond dynamics of the atom-field energy exchange. We find two configurations in which this is possible. The first involves multiphoton transitions between bound states that result in interference between different excitation pathways. The second involves the modification of the bound state absorption lines by the IR field, which we find can result in a subcycle time dependence only when ionization limits the duration of the strong-field interaction.
In this brief review a number of different experimental techniques that combine the advantages of laser and electron interactions with atoms and molecules will be described. These processes range from super-elastic electron scattering from laser excited atoms so as to ascertain the electron collision parameters over all scattering geometries, through new electron interactions with laser cooled and trapped atoms, to the process of electron impact ionization of laser-aligned targets. Examples from work carried out in Manchester are given, and new types of measurements that may be possible in the future are described. © 2010 IOP Publishing Ltd.