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

Soviet Journal of Quantum Electronics

Extended two-level model of multiphoton absorption

Joseph H. Eberly, Stephen V. O'Neil, Jacob L. F. de Meijere

Published Oct 31, 1980• 0 citations
Publisher

Abstract

An analysis is made of a two-level model of multiphoton absorption in the specific case of four-photon ionization of a cesium atom. Allowance is made for the damping and level-shift effects. An expression is obtained for the overall ionization rate and a comparison is made between the theoretical and experimental results.
DOI
10.1070/qe1980v010n10abeh010534

Related papers

Theory of resonant multiphoton ionization: Application to the cesium atom

Yves Gontier, M. Trahin

A quantitative treatment is carried out for the exact operator expressions derived in a previous paper. The formalism of the dressed atom and the concept of level crossings (anticrossings) are used throughout and provide a basis for the quantitative investigation of the resonant three- and four-photon ionization of cesium. The numerical results obtained within this framework are in excellent agreement with experimental observations.

Physical Review A•Jan 1, 1979•97 citations

ATOMS INTERACTING WITH ELECTROMAGNETIC FIELDS, MULTIPHOTON IONIZATION

G. Mainfray

The non linear interaction between an intense laser radiation and atoms leads to ionization through the absorption of N photons from the laser radiation via laser-induced virtual states. The multiphoton ionization rate varies as a function of the laser intensity I as IN. We discuss the two most important effects which govern multiphoton ionization processes : resonance effects and laser-coherence effects. In a moderate laser intensity range (107 - 109 W cm-2) corresponding to the two, three or four-photon ionization of atoms, resonance effects play a dominant role while the photon statistics of the laser radiation are relatively unimportant. On the contrary, in the very high intensity range (1012 - 1013 W cm-2) required to observe large Nth - order ionization processes, coherence effects play a dominant role through N! enhancement in the N-photon ionization rate, while resonance effects are completely damped due to the high laser intensity. We conclude by reviewing the possible applications of multiphoton absorption processes in other fields.

Le Journal de Physique Colloques•Nov 1, 1982•1 citation

Analysis of Multiphoton Transitions within the Two-Level Scheme

Tatiana I. Kuznetsova

Abstract The contribution of a single pair of energy levels to multiphoton absorption under pulsed optical pumping is discussed. A simplified model is proposed to describe multiphoton ionization, which allows approximate estimates of the process rate as a function of system parameters.

Bulletin of the Lebedev Physics Institute•Dec 1, 2022•0 citations

Theory of multiphoton ionization: Near-resonance effects in two-photon ionization

P. Lambropoulos

I present a perturbation theory of multiphoton ionization based on the resolvent operator. The theory is applied to a detailed study of two-photon ionization under near-resonance conditions. It is shown that a distinction must be made between linear level shifts and widths, and resonance shifts and widths which appear in the transition probability. The resonance shifts and widths exhibit saturation effects and their values tend to be much smaller than those of the linear level shifts and widths. Using numerical examples corresponding to tunable dye lasers and alkali-metal atoms, we show that the above shifts can have a dramatic effect on the ionization rate even when the laser is not in exact resonance with the intermediate level. The question of "one-step" vs "two-step" two-photon ionization is also discussed. It is shown that exact resonance does not necessarily imply a two-step process. In fact, in most cases it is quite the opposite. A quantitative criterion for this distinction is established. Finally, a distinction is made between instrumental saturation and saturation of the transition probability. The two are shown to be of different nature. Further extensions of the work are also discussed.

Physical Review A•May 1, 1974•104 citations

Experimental multiphoton ionization of cesium atoms through the 9D 3/2 resonant level

G. Brincourt

In this letter we report the results of an experiment concerning the multiphoton ionization of cesium atoms through the 9D3/2 resonant level, using a ruby laser. The experimental dispersion curve of the resonance obtained is compared to the theoretical shape of the resonant multiphoton ionization profile for cesium deduced from the calculations of B. L. Beers and L. Armstrong [1].

Journal de Physique Lettres•Jan 1, 1977•3 citations

Effects of ionization and cascade decay on two-photon two-level interactions

Barbara A. Capron, Murray Sargent

We extend the semiclassical two-photon two-level model to include upper-level ionization and upper-level decay via an intermediate level. We examine the effects of these relaxation mechanisms on multiwave interactions, finding the generalized one- and two-wave two-photon absorption coefficients and the three-wave coupling coefficient. These mechanisms cause asymmetries to appear in the absorption spectra in addition to those caused by Stark shifts. The Stark-shift term becomes more complicated and fails to vanish even when it does in the simpler model. For recombination rates and ionization decay rates comparable to the coherence decay rate, coherent dips fill in.

Physical Review A•Oct 1, 1986•6 citations
The non linear interaction between an intense laser radiation and atoms leads to ionization through the absorption of N photons from the laser radiation via laser-induced virtual states. The multiphoton ionization rate varies as a function of the laser intensity I as IN. We discuss the two most important effects which govern multiphoton ionization processes : resonance effects and laser-coherence effects. In a moderate laser intensity range (107 - 109 W cm-2) corresponding to the two, three or four-photon ionization of atoms, resonance effects play a dominant role while the photon statistics of the laser radiation are relatively unimportant. On the contrary, in the very high intensity range (1012 - 1013 W cm-2) required to observe large Nth - order ionization processes, coherence effects play a dominant role through N! enhancement in the N-photon ionization rate, while resonance effects are completely damped due to the high laser intensity. We conclude by reviewing the possible applications of multiphoton absorption processes in other fields.
I present a perturbation theory of multiphoton ionization based on the resolvent operator. The theory is applied to a detailed study of two-photon ionization under near-resonance conditions. It is shown that a distinction must be made between linear level shifts and widths, and resonance shifts and widths which appear in the transition probability. The resonance shifts and widths exhibit saturation effects and their values tend to be much smaller than those of the linear level shifts and widths. Using numerical examples corresponding to tunable dye lasers and alkali-metal atoms, we show that the above shifts can have a dramatic effect on the ionization rate even when the laser is not in exact resonance with the intermediate level. The question of "one-step" vs "two-step" two-photon ionization is also discussed. It is shown that exact resonance does not necessarily imply a two-step process. In fact, in most cases it is quite the opposite. A quantitative criterion for this distinction is established. Finally, a distinction is made between instrumental saturation and saturation of the transition probability. The two are shown to be of different nature. Further extensions of the work are also discussed.
We extend the semiclassical two-photon two-level model to include upper-level ionization and upper-level decay via an intermediate level. We examine the effects of these relaxation mechanisms on multiwave interactions, finding the generalized one- and two-wave two-photon absorption coefficients and the three-wave coupling coefficient. These mechanisms cause asymmetries to appear in the absorption spectra in addition to those caused by Stark shifts. The Stark-shift term becomes more complicated and fails to vanish even when it does in the simpler model. For recombination rates and ionization decay rates comparable to the coherence decay rate, coherent dips fill in.