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

Optics and Spectroscopy

Influence of the laser-induced continuum structure on cross sections of the over threshold scattering of photons on atom

Грызлова Елена Владимировна, Alexandr I. Magunov, С. И. Страхова

Published Feb 1, 2011• 3 citations
Publisher

Abstract

Process of photon scattering on atoms is considered at energy above the ionization threshold. Influence of the resonant structure in the continuum, induced by a laser field due to coupling with the level 41 S in helium, on the cross sections of elastic and inelastic scattering of a probe radiation on atom in the meta-stable state 21 S is theoretically investigated. In the rotating wave approximation approach dependences of resonant scattering cross sections on the probe and laser radiation characteristics are obtained. The frequency and polarization dependences of the scattering cross sections to the final states of atom 11 S, 21 S and 41 S are calculated.

DOI
10.1134/s0030400x11020081

Related papers

Angular distribution and polarization of photons during resonant above-threshold scattering on an atom

Грызлова Елена Владимировна, Alexandr I. Magunov, С. И. Страхова

The effect of the resonant structure in the continuous spectrum induced by an external laser field due to the coupling of continuum states with the 1s4s 1 S level in helium on cross sections of elastic and inelastic scattering of probe radiation on an atom in the metastable 1s2s 1 S state at an energy above the ionization threshold is theoretically studied. Explicit expressions for the angular distribution and the degree of polarization of scattered photons as functions of probe and laser radiation characteristics are derived in the rotating wave approximation. Frequency, angular, and polarization dependences of the cross sections of scattering into final 1s 2 1 S, 1 s2s 1 S, and 1s4s 1 S atomic states are calculated.

Bulletin of the Lebedev Physics Institute•Dec 1, 2010•0 citations

Manipulating Feshbach resonances in collisions of atoms in laser radiation field

A. D. Gazazyan, E. A. Gazazyan, V. O. Chaltykyan

Collisions of atoms with formation of Feshbach resonances in the presence of laser field are considered. The elastic and inelastic scattering cross sections are calculated. The laser field leads to second resonance in elastic scattering, broadening of resonances, and arising of interference between resonant and potential scattering. The effects associated with interference of the two channels of decay of bound system of two atoms (a molecule) in laser field are studied. It is shown that if the energy equals that of the lower stable Stark-shifted level plus the energy of two photons, the resonance is quenched. It is also shown that with the increase in two-photon effective interaction the pattern of resonance scattering changes essentially.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 29, 2010•1 citation

Electron-atom scattering in a resonant laser field

K. Unnikrishnan

Dressed states of an atom in a classical laser field of frequency close to an atomic transition frequency are obtained, which are a considerable improvement over the usual two-level rotating-wave approximation. These wave functions are used in a calculation of the cross section for elastic electron-atom scattering in a laser field. Numerical calculations for electron-hydrogen scattering demonstrate that scattering involving absorption or emission of photons can be strongly influenced by coupling to the nonresonant states, regardless of the field strength. Inclusion of the counter-rotating terms in the calculation is shown to be essential for extending the applicability of the theory to scattering in nonresonant fields, where a first-order perturbation-theoretic treatment of the atom-field interaction would be expected to be quite justified.

Physical Review A•Sep 1, 1988•15 citations

Photoionisation of a helium atom involving autoionisation states coupled by a circularly polarised laser field

Грызлова Елена Владимировна, Alexandr I. Magunov, I. Rotter +1 more

The rotating wave approximation is used to obtain parametric expressions for the resonance cross section for the atomic ground state ionisation by linearly polarised probe radiation in the vicinity of an autoionisation state coupled resonantly to another autoionisation state through circularly polarised laser radiation. Calculations are made for the 2s2p 1 P and 2s3d 1 D states of the helium atom. It is shown that the structure of the photoionisation cross-section spectrum formed for circularly polarised laser radiation differs qualitatively from the structure formed in the case of linear polarisation. The dependence of this structure on the intensity and frequency of laser radiation and the direction of polarisation of the probe radiation is studied.

Quantum Electronics•Jan 31, 2005•3 citations

Collision of atoms with formation of Feshbach resonance in the case of the coupled decay channels with the presence of laser radiation

E. A. Gazazyan, A. D. Gazazyan, V. O. Chaltykyan

Resonance scattering with formation of Feshbach resonance in the presence of laser radiation in the case of the decays in open and closed channels is considered. The presence of the resonant laser radiation leads to additional channels of the elastic and inelastic scattering. The cross sections of the elastic and inelastic scattering are obtained which show that they are determined by two interconnected phases of resonance scattering and interference phenomena are observed.

Journal of Physics Conference Series•Mar 14, 2012•0 citations

Collision of atoms under action of external magnetic and laser radiation fields with formation of Fano-Feshbach resonances

E. A. Gazazyan, A. D. Gazazyan, V. O. Chaltykyan

We investigate collision of two atoms in an external magnetic field and in the field of laser radiation with formation of Fano-Feshbach resonances. At one-photon resonance of laser radiation with two discrete vibrational states of molecule the dressed states are formed (Autler-Townes effect) which form Fano-Feshbach resonances in interaction with the external magnetic field. In addition, the lower molecular vibrational state is coupled with the continuum of the elastic channel via also LICS (laser-induced continuum structure) forming laser-induced resonance. We obtain cross-sections of elastic and inelastic resonant scattering and expression for the scattering length depending on the external magnetic and laser radiation fields.

Journal of Contemporary Physics (Armenian Academy of Sciences)•Nov 1, 2012•1 citation
Process of photon scattering on atoms is considered at energy above the ionization threshold. Influence of the resonant structure in the continuum, induced by a laser field due to coupling with the level 41 S in helium, on the cross sections of elastic and inelastic scattering of a probe radiation on atom in the meta-stable state 21 S is theoretically investigated. In the rotating wave approximation approach dependences of resonant scattering cross sections on the probe and laser radiation characteristics are obtained. The frequency and polarization dependences of the scattering cross sections to the final states of atom 11 S, 21 S and 41 S are calculated.
The effect of the resonant structure in the continuous spectrum induced by an external laser field due to the coupling of continuum states with the 1s4s 1 S level in helium on cross sections of elastic and inelastic scattering of probe radiation on an atom in the metastable 1s2s 1 S state at an energy above the ionization threshold is theoretically studied. Explicit expressions for the angular distribution and the degree of polarization of scattered photons as functions of probe and laser radiation characteristics are derived in the rotating wave approximation. Frequency, angular, and polarization dependences of the cross sections of scattering into final 1s 2 1 S, 1 s2s 1 S, and 1s4s 1 S atomic states are calculated.
Collisions of atoms with formation of Feshbach resonances in the presence of laser field are considered. The elastic and inelastic scattering cross sections are calculated. The laser field leads to second resonance in elastic scattering, broadening of resonances, and arising of interference between resonant and potential scattering. The effects associated with interference of the two channels of decay of bound system of two atoms (a molecule) in laser field are studied. It is shown that if the energy equals that of the lower stable Stark-shifted level plus the energy of two photons, the resonance is quenched. It is also shown that with the increase in two-photon effective interaction the pattern of resonance scattering changes essentially.
Dressed states of an atom in a classical laser field of frequency close to an atomic transition frequency are obtained, which are a considerable improvement over the usual two-level rotating-wave approximation. These wave functions are used in a calculation of the cross section for elastic electron-atom scattering in a laser field. Numerical calculations for electron-hydrogen scattering demonstrate that scattering involving absorption or emission of photons can be strongly influenced by coupling to the nonresonant states, regardless of the field strength. Inclusion of the counter-rotating terms in the calculation is shown to be essential for extending the applicability of the theory to scattering in nonresonant fields, where a first-order perturbation-theoretic treatment of the atom-field interaction would be expected to be quite justified.
The rotating wave approximation is used to obtain parametric expressions for the resonance cross section for the atomic ground state ionisation by linearly polarised probe radiation in the vicinity of an autoionisation state coupled resonantly to another autoionisation state through circularly polarised laser radiation. Calculations are made for the 2s2p 1 P and 2s3d 1 D states of the helium atom. It is shown that the structure of the photoionisation cross-section spectrum formed for circularly polarised laser radiation differs qualitatively from the structure formed in the case of linear polarisation. The dependence of this structure on the intensity and frequency of laser radiation and the direction of polarisation of the probe radiation is studied.
We investigate collision of two atoms in an external magnetic field and in the field of laser radiation with formation of Fano-Feshbach resonances. At one-photon resonance of laser radiation with two discrete vibrational states of molecule the dressed states are formed (Autler-Townes effect) which form Fano-Feshbach resonances in interaction with the external magnetic field. In addition, the lower molecular vibrational state is coupled with the continuum of the elastic channel via also LICS (laser-induced continuum structure) forming laser-induced resonance. We obtain cross-sections of elastic and inelastic resonant scattering and expression for the scattering length depending on the external magnetic and laser radiation fields.