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

Acta Physica Sinica

NON-EQUILIBRIUM DISTRIBUTION OF THE POPULATION OF ALKALI ATOMS IN THE GROUND STATE INDUCED BY LASER-MW DOUBLE RESONANCES

CHEN XIAO-YUAN, Xiwen Zhu, 中国科学院武汉物理研究所

Published Jan 1, 1987• 0 citations
Publisher

Abstract

We obtained the conditions under which the maximum non-equilibrium distribution of the population of alkali atoms in the ground state in atomic beam pumped by laser-MW double resonance is achieved. These conditions are consistent with recent experiments. We examined the processes which affect the realization of the non-equilibrium distribution of population, and indicated the methods of eliminating the effects of these processes. The features of pumping processes with laser-MW double resonances are discussed, and compared with the two laser pumping process.

DOI
10.7498/aps.36.436

Related papers

Optical--microwave pumping of alkali atoms and population capture

Evgenii B. Aleksandrov, Anton K. Vershovskii

The steady-state distribution of the populations of the hyperfine sublevels of the ground state of alkali atoms is calculated for the case in which the atoms are subjected to a spectrally selective optical pumping on /sup 2/S/sub 1//sub ///sub 2/--/sup 2/P/sub 1/2,3/2/ transitions and a simultaneous pumping by microwave fields which are at resonance with transitions in the hyperfine structure of the ground state, F-italic = 2, M-italic/sub F-italic/ = +- 2, +- 1bold-arrow-left-rightF-italic = 1, M-italic/sub F-italic/ = +- 1. The addition of the microwave pumping is shown to substantially increase the population difference for the O--O transition in the hyperfine structure. During selective optical pumping of the F-italic = 1 level, the population inversion which can be achieved for the O--O transition is limited by the effect of population capture. This capture can be eliminated by using incoherent microwave fields. The quality factor of the O--O resonance is calculated as a function of the parameters of the pump. The outlook for the use of composite pumping in frequency-stabilization systems is discussed.

Optics and Spectroscopy•Dec 1, 1985•0 citations

Production of Atomic Alkali-Metal Beams in Single Hyperfine Sublevels

W. Dreves, H.J. Jänsch, Edmund Koch +1 more

A compact source which produces atomic alkali-metal beams in individual hyperfine sublevels has been developed. The methods are demonstrated with $^{23}\mathrm{Na}$ atoms. Initially nearly all atoms are transferred into one hyperfine sublevel ($|F, {m}_{F}〉=|2, 2〉$) by a double-resonance technique using laser optical pumping and rf transitions. Subsequently the other hyperfine sublevels can be populated selectively by an adiabatic high-frequency transition. The hyperfine sublevel populations are determined by laser-induced fluorescence spectroscopy in a magnetic field.

Physical Review Letters•May 30, 1983•50 citations

Coherent trapping of atomic populations

H. R. Gray, R. M. Whitley, Carlos R. Stroud

It is often desirable in laser spectroscopy and isotope separation to extract as much as possible of an atomic or molecular population that is distributed among a number of ground-state sublevels and low-lying metastable levels. We describe a form of coherent trapping that occurs when multiple resonant laser beams are used to couple the various ground states to a common upper level. This effect prevents the extraction of the entire population. We then study the effect with two dye lasers and an atomic beam and suggest possible ways to maximize the pumping efficiency.

Optics Letters•Dec 1, 1978•768 citations

Particularities of optical pumping effects in cold and ultra-slow beams of Na and Cs in the case of cyclic transitions

Martins Bruvelis, A. Cinins, Aleksandrs Leitis +5 more

The time-dependent population dynamics of hyperfine (HF) levels of n 2 p 3/2 states is examined for cyclic transitions in alkali atoms. We study a slow and cold atomic beam of Na (n = 3) and Cs (n = 6), taking into account the long interaction time of light with atoms (~200 μs) inside the resonant laser beam. Simple analytical expressions for the populations of the excited states and for the intensities of the absorption lines are derived for a three-level system model. We show that at moderate pump laser power the mixing of HF levels is sufficient to form a flow of population from a cyclic transition to partially open transitions. We discuss various phenomena associated with the evolution of optical pumping that cannot be explained by general analysis of two-level system model.

Optics and Spectroscopy•Dec 1, 2015•4 citations

Detailed look at aspects of optical pumping in sodium

Jabez J. McClelland, Michael H. Kelley

Calculations and measurements are presented of the increase in F\ifmmode\bar\else\textasciimacron\fi{}=1 ground-state population as a function of incident laser intensity in optically pumped sodium. The calculations involve numerical integration of a multilevel version of the optical Bloch equations. Agreement between experiment and theory is good when proper account is taken of the residual Doppler width in the atomic beam, which causes a larger increase in the F\ifmmode\bar\else\textasciimacron\fi{}=1 population. The F\ifmmode\bar\else\textasciimacron\fi{}=1 population increases by 3.5% at 35 mW/${\mathrm{cm}}^{2}$, the highest laser intensity investigated.

Physical Review A•Jun 1, 1985•78 citations

Lasing and phase transition in atomic system with dressed states

Igor Yu. Chestnov, A. P. Alodjants, Sergei M Arakelyan

The problem of phase transitions in the system of high-density gas of two-level atoms non-resonantly interacting with a pump field in the presence of optical collisions (OCs) and placed in the cavity is studied. The OCs are considered in the framework of thermalization of atomic dressed state (DS) population. For the case of a strong atom-field coupling condition we analyze the problem of thermodynamic equilibrium superradiant phase transition for the order parameter representing real amplitude of cavity mode and taking place as a result of the atomic DS thermalization process. At the same time such a transition can be connected with condensed (coherent) properties of low branch DS-polaritons occurring in the cavity. Various aspects of non-equilibrium phase transition to laser field generation by using atomic DS levels are studied in detail. It is important that for positive atom-light detuning DS lasing can be obtained in the presence of quasi-equilibrium DS population that corresponds to a true two-level atomic system with inversion in perturbative limit.

Laser Physics•May 29, 2014•0 citations
We obtained the conditions under which the maximum non-equilibrium distribution of the population of alkali atoms in the ground state in atomic beam pumped by laser-MW double resonance is achieved. These conditions are consistent with recent experiments. We examined the processes which affect the realization of the non-equilibrium distribution of population, and indicated the methods of eliminating the effects of these processes. The features of pumping processes with laser-MW double resonances are discussed, and compared with the two laser pumping process.
The steady-state distribution of the populations of the hyperfine sublevels of the ground state of alkali atoms is calculated for the case in which the atoms are subjected to a spectrally selective optical pumping on /sup 2/S/sub 1//sub ///sub 2/--/sup 2/P/sub 1/2,3/2/ transitions and a simultaneous pumping by microwave fields which are at resonance with transitions in the hyperfine structure of the ground state, F-italic = 2, M-italic/sub F-italic/ = +- 2, +- 1bold-arrow-left-rightF-italic = 1, M-italic/sub F-italic/ = +- 1. The addition of the microwave pumping is shown to substantially increase the population difference for the O--O transition in the hyperfine structure. During selective optical pumping of the F-italic = 1 level, the population inversion which can be achieved for the O--O transition is limited by the effect of population capture. This capture can be eliminated by using incoherent microwave fields. The quality factor of the O--O resonance is calculated as a function of the parameters of the pump. The outlook for the use of composite pumping in frequency-stabilization systems is discussed.
A compact source which produces atomic alkali-metal beams in individual hyperfine sublevels has been developed. The methods are demonstrated with 23Na^{23}\mathrm{Na}23Na atoms. Initially nearly all atoms are transferred into one hyperfine sublevel (∣F,mF〉=∣2,2〉|F, {m}_{F}〉=|2, 2〉∣F,mF​〉=∣2,2〉) by a double-resonance technique using laser optical pumping and rf transitions. Subsequently the other hyperfine sublevels can be populated selectively by an adiabatic high-frequency transition. The hyperfine sublevel populations are determined by laser-induced fluorescence spectroscopy in a magnetic field.
It is often desirable in laser spectroscopy and isotope separation to extract as much as possible of an atomic or molecular population that is distributed among a number of ground-state sublevels and low-lying metastable levels. We describe a form of coherent trapping that occurs when multiple resonant laser beams are used to couple the various ground states to a common upper level. This effect prevents the extraction of the entire population. We then study the effect with two dye lasers and an atomic beam and suggest possible ways to maximize the pumping efficiency.
The time-dependent population dynamics of hyperfine (HF) levels of n 2 p 3/2 states is examined for cyclic transitions in alkali atoms. We study a slow and cold atomic beam of Na (n = 3) and Cs (n = 6), taking into account the long interaction time of light with atoms (~200 μs) inside the resonant laser beam. Simple analytical expressions for the populations of the excited states and for the intensities of the absorption lines are derived for a three-level system model. We show that at moderate pump laser power the mixing of HF levels is sufficient to form a flow of population from a cyclic transition to partially open transitions. We discuss various phenomena associated with the evolution of optical pumping that cannot be explained by general analysis of two-level system model.
Calculations and measurements are presented of the increase in F\ifmmode\bar\else\textasciimacron\fi{}=1 ground-state population as a function of incident laser intensity in optically pumped sodium. The calculations involve numerical integration of a multilevel version of the optical Bloch equations. Agreement between experiment and theory is good when proper account is taken of the residual Doppler width in the atomic beam, which causes a larger increase in the F\ifmmode\bar\else\textasciimacron\fi{}=1 population. The F\ifmmode\bar\else\textasciimacron\fi{}=1 population increases by 3.5% at 35 mW/cm2{\mathrm{cm}}^{2}cm2, the highest laser intensity investigated.
The problem of phase transitions in the system of high-density gas of two-level atoms non-resonantly interacting with a pump field in the presence of optical collisions (OCs) and placed in the cavity is studied. The OCs are considered in the framework of thermalization of atomic dressed state (DS) population. For the case of a strong atom-field coupling condition we analyze the problem of thermodynamic equilibrium superradiant phase transition for the order parameter representing real amplitude of cavity mode and taking place as a result of the atomic DS thermalization process. At the same time such a transition can be connected with condensed (coherent) properties of low branch DS-polaritons occurring in the cavity. Various aspects of non-equilibrium phase transition to laser field generation by using atomic DS levels are studied in detail. It is important that for positive atom-light detuning DS lasing can be obtained in the presence of quasi-equilibrium DS population that corresponds to a true two-level atomic system with inversion in perturbative limit.