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

Europhysics Letters (EPL)

Collision photography: Imaging of ultrafast atomic processes

Joachim Großer, O. Hoffmann, Frank Rebentrost

Published Apr 1, 2002• 3 citations
Publisher

Abstract

We study the laser excitation of atomic collision pairs in a differential scattering experiment. The interference structure in the differential cross-section is resolved and shows a considerable variation with the linear polarization of the laser light. A systematic analysis allows the accurate determination of the Condon vectors characterizing the optical transition. The method is thus capable to directly visualize geometric aspects of the collision event, very much like an everyday photography.

DOI
10.1209/epl/i2002-00624-x

Related papers

Analysis and manipulation of atomic and molecular collisions using laser light

A. Grimpe

Optical collisions in a crossed beam experiment are examined for the atomic collision pairs LiHe, LiNe, NaNe.Differential cross sections are measured in order to probe the quallity of quantum chemical calculated and spectroscopical determined molecular potentials.The linear polarization of the excitation laser is used to manipulate the contrast of the differential cross sections for NaNe.Using elliptical polarized light total control over the angular position and the contrast of the interference pattern is demonstrated.Differential cross sections for the collision pairs LiH and LiD show a pronounced oscillatory structure, which for the first time is observed for atom-molecule optical collisions.

•Jan 1, 2006•0 citations

Optical collisions in an atomic beam experiment

Joachim Großer, O. Hoffmann, Selina Klose

The optical collision Na(3s)+Kr+hν→Na(3p)+Kr has been investigated in an experiment with crossed atomic beams and with a differential detection of the excited collision products. Three groups of experimental results have been obtained, which all demonstrate unprecedented possibilities for the observation of atomic collisions. 1. The oscillatory structure of the differential cross sections allows a sensitive test of the molecular potentials. 2. Polarization experiments give direct information about the geometric characteristics of the collision complex. 3. State analysis of the collision products provides a tool for the observation of elementary nonadiabatic processes. A number of possible future experiments, which make use of the new ideas, is discussed, in addition.

AIP conference proceedings•Jan 1, 1997•1 citation

Electron-atom collision studies using optically state selected beams. Progress report, 1 May 1985-30 April 1986

R. J. Celotta, Michael H. Kelley

Collisions studies using optically state selected beams is discussed. Measurements of spin resolved differential cross sections for superelastic scattering of electrons from excited sodium atoms (3P) are reported. The excited states are prepared by laser optical pumping with circularly polarized light thus giving a pure atomic state before the collision. A crossed beam arrangement of sodium atoms and electrons is used with a scattered electron detector. Scattered electron intensity as a function of scattering angle, incident electron energy, and relative orientation of the incident electronic and atomic spins is measured. 8 refs., 10 figs.

•Jan 1, 1986•0 citations

Measurement of the collision-induced alignment in the differential scattering by laser-excited atoms: 3P to nS transitions excited by electron scattering on sodium

Heinz W. Hermann, Ingolf Volker Hertel, Werner Reiland +2 more

Electron scattering by excited sodium atoms has been carried out in a crossed-beam experiment. The atoms have been optically pumped into a well defined hyperfine level (3 2 P 3 2/F=3) by a tunable CW dye laser. For two of the most prominent scattering processes, the 3 2 P to 3 2 S and 3 2 P to 4 2 S transitions, the effect of the anisotropy of the initial state introduced by the laser light is studied in detail and is interpreted in terms of multipole moments describing the optical excitation and the collision process. Possibilities and limitations of the experiment are discussed. Electron collisions may be seen as a test case for the understanding of more involved interaction processes.

Journal of Physics B Atomic and Molecular Physics•Feb 1, 1977•59 citations

Differential cross sections for radiation assisted collisions between atoms

Joachim Großer, D Hohmeier, Selina Klose

We report angle resolved measurements of the excited Na atoms from the process with non-resonant light. The experiment provides a method to probe the NaKr collision pair by a photon. The Na( ) angular distribution shows an oscillatory structure, which can be used for a test of the NaKr potential curve system. The signal depends strongly upon the polarization of the photon. The effect provides information about the geometric properties of the collision pair.

Journal of Physics B Atomic Molecular and Optical Physics•Jan 28, 1996•9 citations

Laser-induced fluorescence and polarized light in the collision regime: the ) case

S. De Benedictis, Giorgio Dilecce, Vito Luigi Lepore

Laser-induced fluorescence experiments carried out using linearly polarized photons from a pulsed laser on a excitation - detection scheme in electrical discharges at 0.04 - 0.6 Torr, show that light emitted during the interaction and in the subsequent decay manifests anisotropy in its angular distribution and polarization. A rate equation approach is used to discuss the general features of the interaction between polarized light and atoms observed experimentally. The incident electromagnetic field is decomposed into multipolar components that may interact with the atom through an appropriate coupling. Defining the Einstein coefficients for each coupling, it is possible to introduce the equations for the dynamics of the atomic populations. For each direction and polarization, the temporal profile of the intensity during the transition is calculated. The theoretical prediction explains the outcome of the He experiment satisfactorily, providing that the role of the quenching and of the collision mixing within the manifold of the state is duly taken into account. Fitting of the model calculations to the experimental data then allows one to deduce the value of the `thermally averaged' cross section for collision-induced transitions between fine-structure and degenerate components of the sublevel, , for each J,M in the manifold.

Journal of Physics B Atomic Molecular and Optical Physics•Dec 14, 1997•1 citation
We study the laser excitation of atomic collision pairs in a differential scattering experiment. The interference structure in the differential cross-section is resolved and shows a considerable variation with the linear polarization of the laser light. A systematic analysis allows the accurate determination of the Condon vectors characterizing the optical transition. The method is thus capable to directly visualize geometric aspects of the collision event, very much like an everyday photography.
Optical collisions in a crossed beam experiment are examined for the atomic collision pairs LiHe, LiNe, NaNe.Differential cross sections are measured in order to probe the quallity of quantum chemical calculated and spectroscopical determined molecular potentials.The linear polarization of the excitation laser is used to manipulate the contrast of the differential cross sections for NaNe.Using elliptical polarized light total control over the angular position and the contrast of the interference pattern is demonstrated.Differential cross sections for the collision pairs LiH and LiD show a pronounced oscillatory structure, which for the first time is observed for atom-molecule optical collisions.
The optical collision Na(3s)+Kr+hν→Na(3p)+Kr has been investigated in an experiment with crossed atomic beams and with a differential detection of the excited collision products. Three groups of experimental results have been obtained, which all demonstrate unprecedented possibilities for the observation of atomic collisions. 1. The oscillatory structure of the differential cross sections allows a sensitive test of the molecular potentials. 2. Polarization experiments give direct information about the geometric characteristics of the collision complex. 3. State analysis of the collision products provides a tool for the observation of elementary nonadiabatic processes. A number of possible future experiments, which make use of the new ideas, is discussed, in addition.
Collisions studies using optically state selected beams is discussed. Measurements of spin resolved differential cross sections for superelastic scattering of electrons from excited sodium atoms (3P) are reported. The excited states are prepared by laser optical pumping with circularly polarized light thus giving a pure atomic state before the collision. A crossed beam arrangement of sodium atoms and electrons is used with a scattered electron detector. Scattered electron intensity as a function of scattering angle, incident electron energy, and relative orientation of the incident electronic and atomic spins is measured. 8 refs., 10 figs.
Electron scattering by excited sodium atoms has been carried out in a crossed-beam experiment. The atoms have been optically pumped into a well defined hyperfine level (3 2 P 3 2/F=3) by a tunable CW dye laser. For two of the most prominent scattering processes, the 3 2 P to 3 2 S and 3 2 P to 4 2 S transitions, the effect of the anisotropy of the initial state introduced by the laser light is studied in detail and is interpreted in terms of multipole moments describing the optical excitation and the collision process. Possibilities and limitations of the experiment are discussed. Electron collisions may be seen as a test case for the understanding of more involved interaction processes.
Laser-induced fluorescence experiments carried out using linearly polarized photons from a pulsed laser on a excitation - detection scheme in electrical discharges at 0.04 - 0.6 Torr, show that light emitted during the interaction and in the subsequent decay manifests anisotropy in its angular distribution and polarization. A rate equation approach is used to discuss the general features of the interaction between polarized light and atoms observed experimentally. The incident electromagnetic field is decomposed into multipolar components that may interact with the atom through an appropriate coupling. Defining the Einstein coefficients for each coupling, it is possible to introduce the equations for the dynamics of the atomic populations. For each direction and polarization, the temporal profile of the intensity during the transition is calculated. The theoretical prediction explains the outcome of the He experiment satisfactorily, providing that the role of the quenching and of the collision mixing within the manifold of the state is duly taken into account. Fitting of the model calculations to the experimental data then allows one to deduce the value of the `thermally averaged' cross section for collision-induced transitions between fine-structure and degenerate components of the sublevel, , for each J,M in the manifold.