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 B Atomic and Molecular Physics

Population trapping in continuum-continuum transitions

Zofia Białynicka-Birula

Published Dec 14, 1983• 13 citations
Publisher

Abstract

An exactly soluble model is used to describe transitions, induced by two strong laser beams, proceeding from the initial discrete state to the continuum via two channels. In the first channel the transition occurs via an intermediate, near-resonant discrete state located close to the continuum edge. In the second channel the intermediate state belongs to the continuum. Population trapping occurs due to an interference between the two channels. The model can be used to describe the photodetachment of electrons from negative ions or the photodissociation of molecules.

DOI
10.1088/0022-3700/16/23/018

Related papers

Threshold effects and photoelectron spectra in model-system descriptions of photodetachment

Stanley L. Haan, P. A. Polstra, W. H. Schotanus +1 more

Near-threshold single-photon photodetachment processes are considered for simple model systems representing negative ions exposed to monochromatic radiation. The model systems considered feature an initial discrete state, the photoelectron continuum, and in some cases an excited or autodetaching discrete state. Population trapping through the formation of a bound dressed state and the photoelectron spectra are examined. Two photoelectron spectra are defined : a primary spectrum which results from decay while the laser interaction is on and a secondary spectrum which results from the destabilization of the bound dressed state if the interaction is turned off again. Careful attention is given to the passage of the poles of the Green's operator through the low-energy boundary of a continuum, and it is concluded that such poles move nonmonotonically through the boundary of an s-wave continuum, but monotonically through the boundary of a p-wave or higher-l-wave continuum. Two example systems, one featuring a single discrete state and an s-wave continuum and one featuring two discrete states and a p-wave continuum, are considered in detail.

Physical Review A•Nov 1, 1992•2 citations

Population trapping in laser-induced continuum-continuum transitions

Kazimierz Rza̧żewski, Joseph W. Haus, L Wang

The authors show that the population trapping phenomenon found by Deng and Eberly (1986, 1988) for free-free transitions between structureless continua occurs under much more general conditions. They solve the time-dependent models exactly and show for asymptotically long times that population trapping can occur for two continua with energy-dependent matrix elements, and for an infinite number of structureless continua with coupled bands. Furthermore, they show that the trapping persists for two continua coupled by a noisy laser. The amount of trapping depends on the initial conditions.

Journal of Physics B Atomic Molecular and Optical Physics•Oct 28, 1989•2 citations

Model photodetachment with two continua

Andrzej Raczyński, Jarosław Zaremba

Non-perturbative, exact, analytical photodetachment spectra for a model negative ion including a single bound state and two continua are calculated with continuum-continuum transitions taken into account. Asymmetric two-peak structures of significant widths are shown to be the typical spectra both for l=1 and for l=2 photoelectrons. The population trapping in the initial state is demonstrated as due to a creation of a bound state of the dressed system.

Journal of Physics B Atomic Molecular and Optical Physics•Feb 14, 1993•2 citations

Coherent trapping in continuum-continuum transitions

Zhifang Deng, Joseph H. Eberly

We study a quantum model in which transitions occur between structureless continua. The population is in one of the continua initially. When the continuum-continuum coupling is very strong, we show that the continua are decoupled and population trapping occurs.

Physical Review A•Sep 1, 1986•16 citations

Laser-induced continuum structure and population trapping in helium (2s1So)

Thomas Halfmann, Леонід Петрович Яценко, M. Shapiro +2 more

In recent years our understanding of how laser fields interact with a continuum of levels has progressed substantially. No longer is the continuum viewed as a dissipative environment, best described by a set of kinetic equations. Recent theoretical* and experimental work has shown that strong laser fields involving a continuum of levels may often maintain perfeet coherence. One of the m ore interesting colterent phenomena involving the continuum is the dressing of a continuum by a bound state, termed laser-induced continuum structure (LICS). In the LICS phenomenon, a strong laser field, connecting an unpopulated bound state to the continuum mixes some bound- state character into the continuum. This optically induced resonance can be detected by a second (weaker) laser field, which induces a transition from a populated bound state to the structured continuum.

•May 3, 1998•0 citations

Selective excitation via the continuum and suppression of ionization

C. E. Carroll, F. T. Hioe

Two laser pulses that overlap in time have been successfully used for coherent excitation of a molecule or atom to a desired state. An intermediate state that is at or near resonance with the laser frequencies has been used in past experiments and calculations. Here we replace this intermediate state by a continuum of intermediate states. An analytic solution of a simple model suggests that the continuum can be used in such an excitation scheme, provided that the laser pulses are arranged in the so-called counterintuitive order. We use a special case of this solution to relate this work to ionization suppression and coherent population trapping.

Physical Review A•Jan 1, 1993•38 citations
An exactly soluble model is used to describe transitions, induced by two strong laser beams, proceeding from the initial discrete state to the continuum via two channels. In the first channel the transition occurs via an intermediate, near-resonant discrete state located close to the continuum edge. In the second channel the intermediate state belongs to the continuum. Population trapping occurs due to an interference between the two channels. The model can be used to describe the photodetachment of electrons from negative ions or the photodissociation of molecules.
Near-threshold single-photon photodetachment processes are considered for simple model systems representing negative ions exposed to monochromatic radiation. The model systems considered feature an initial discrete state, the photoelectron continuum, and in some cases an excited or autodetaching discrete state. Population trapping through the formation of a bound dressed state and the photoelectron spectra are examined. Two photoelectron spectra are defined : a primary spectrum which results from decay while the laser interaction is on and a secondary spectrum which results from the destabilization of the bound dressed state if the interaction is turned off again. Careful attention is given to the passage of the poles of the Green's operator through the low-energy boundary of a continuum, and it is concluded that such poles move nonmonotonically through the boundary of an s-wave continuum, but monotonically through the boundary of a p-wave or higher-l-wave continuum. Two example systems, one featuring a single discrete state and an s-wave continuum and one featuring two discrete states and a p-wave continuum, are considered in detail.
The authors show that the population trapping phenomenon found by Deng and Eberly (1986, 1988) for free-free transitions between structureless continua occurs under much more general conditions. They solve the time-dependent models exactly and show for asymptotically long times that population trapping can occur for two continua with energy-dependent matrix elements, and for an infinite number of structureless continua with coupled bands. Furthermore, they show that the trapping persists for two continua coupled by a noisy laser. The amount of trapping depends on the initial conditions.
In recent years our understanding of how laser fields interact with a continuum of levels has progressed substantially. No longer is the continuum viewed as a dissipative environment, best described by a set of kinetic equations. Recent theoretical* and experimental work has shown that strong laser fields involving a continuum of levels may often maintain perfeet coherence. One of the m ore interesting colterent phenomena involving the continuum is the dressing of a continuum by a bound state, termed laser-induced continuum structure (LICS). In the LICS phenomenon, a strong laser field, connecting an unpopulated bound state to the continuum mixes some bound- state character into the continuum. This optically induced resonance can be detected by a second (weaker) laser field, which induces a transition from a populated bound state to the structured continuum.
Two laser pulses that overlap in time have been successfully used for coherent excitation of a molecule or atom to a desired state. An intermediate state that is at or near resonance with the laser frequencies has been used in past experiments and calculations. Here we replace this intermediate state by a continuum of intermediate states. An analytic solution of a simple model suggests that the continuum can be used in such an excitation scheme, provided that the laser pulses are arranged in the so-called counterintuitive order. We use a special case of this solution to relate this work to ionization suppression and coherent population trapping.