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

Physical Review A

Examination of subnatural spectroscopy using optical pumping

James C. Camparo, R. P. Frueholz, Charles M. Klimcak

Published Sep 1, 1987• 1 citation
Publisher

Abstract

Recent experiments have shown that optical pumping can produce line shapes with subnatural structure, and that this structure could prove to be useful for extracting oscillator strengths. A key question, however, regarding the optical-pumping technique's potential usefulness is how well it allows the determination of resonance line center. In the present paper we address this question theoretically by considering laser optical pumping and probing of an atomic beam. From the analysis (i) we find that depending on laser polarization the optical-pumping subnatural feature is either a dip or a signal enhancement, (ii) we derive the rigorously correct formula relating the dip width to the transition oscillator strength for an alkali-like atom exhibiting a homogeneous line shape, and (iii) we show that, compared to shot-noise-limited laser-induced fluorescence, the optical-pumping technique of signal enhancement is capable of a 15% improvement in the ability to find resonance line center.

DOI
10.1103/physreva.36.2072

Related papers

Subnatural optical pumping dips

Charles M. Klimcak, James C. Camparo, Robert Cook +1 more

The technique of optical pumping dips has been employed to generate subnatural structure in a $^{87}\mathrm{Rb}$ ${D}_{1}$ line (natural width 5.6 MHz). Structure as narrow as 1.4 MHz was observed. These experiments represent the first observation of subnatural spectral structure generated without requiring atomic coherence. Additionally, line shapes observed in these studies may be analyzed to yield transition dipole moments without requiring internal standards or an absolute calibration of fluorescence collection efficiency in the experimental apparatus.

Physical Review A•Aug 1, 1986•1 citation

Observation of optical pumping effects in collinear atomic beam - laser beam(s) interaction

N. Bendali, H. T. Duong, J.M. Saint Jalm +1 more

The detection of optical resonances by observation of the fluorescence light emitted from a fast atomic beam of Na interacting with a collinear laser beam is limited in sensitivity by optical pumping processes. In the experiment reported here, we take advantage of the optical pumping by using a second collinear laser beam, achieving then a gain in fluorescence signal. The effects of the lasers power and polarization on line shapes have been studied in the single laser excitation case as well as in the two laser beams one.

Journal de physique•Jan 1, 1983•7 citations

Sub-atomic-natural linewidth optical-pumping dips in a homogeneously broadened spectral line

Meng-Yang Li, J. S. Fu

We observed sub-atomic-natural linewidth optical-pumping dips in a homogeneously broadened fluorescence line in Na atomic beam spectroscopy. To our knowledge this is the first observation of sub-atomic-natural linewidth dip by optical pumping. The theoretic explanation has been given out.

•Nov 1, 1985•0 citations

Anomalies in the shape of atomic resonant absorption lines under conditions of strong optical pumping of hyperfine structure components of the ground state

А. И. Пархоменко, S.P. Pod'yachev, Timofei Privalov +1 more

The ground electronic state of even such simple atoms as those of alkali elements has the set of sublevels. These sublevels are hyperfine (HF) components and magnetic sublevels. The collisions with particles of nonmagnetic buffer gas or even with walls (when walls have proper coating) do not mix practically the populations of ground state HF sublevels, if the orbital moment of electrons in the ground state is equal to zero. Due to this reason these sublevels may be extremely long lived. Because of this, for instance, the so-called effects of optical orientation and optical pumping are apparent in atoms of alkali metals. The radiation can pump practically all the atoms (with which there is effective interaction) to a single HF component. In a situation in which optical pumping is a minor effect, the monochromatic absorption line consists of separate lines corresponding to intra-atomic transitions. The optical pumping is not significant, for example, if the radiation intensity is so low that now pumping between HF sublevels occurs in the time it takes the atom to traverse the light beam. Under the conditions of optical pumping and when other nonlinear effects are present, the absorption line profile can undergo considerable alteration. Many theoretical and experimental investigations have been done in the laser spectroscopy of resonant transitions of atoms (atoms of alkali metals) under the conditions of optical pumping within ground state HF structure. A characteristic feature of all such investigations is the velocity-selective excitation of absorbing atoms. Also, as a rule, the value of HF splitting is not very big in comparison to Doppler broadening in these experiments. Under such conditions, the absorption spectra consists of Doppler- broadened lines with nonlinear resonances, which emerge when two fields of different frequencies or different propagation directions are employed. When only one monochromatic traveling wave is employed, optical pumping leads to formation of a single smooth absorption line occupying a position between the resonant transitions frequencies associated with HF components. As HF splitting grows, the line profile remains smooth, its width is approximately equal to the size of the HF splitting. The strength of the optical pumping from one ground state HF component to another is greater for greater HF splitting in comparison to the Doppler width. In this regard, Cs and Rb are the most typical of the alkali atoms (the HF splitting exceeds the Doppler width by a factor close to 20). This is the qualitative picture of the absorption line profile (particularly for a monochromatic radiation) under the conditions of optical pumping between the HF sublevels of the electronic ground state, this qualitative picture had formed by now.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 21, 1998•0 citations

Polarization-rotation resonances with subnatural widths using a control laser

Sapam Ranjita Chanu, Kanhaiya Pandey, Vineet Bharti +2 more

We demonstrate extremely narrow resonances for polarization rotation in an atomic vapor. The resonances are created using a strong control laser on the same transition, which polarizes the atoms due to optical pumping among the magnetic sublevels. As the power in the control laser is increased, successively higher-order nested polarization-rotation resonances are created, with progressively narrower linewidths. We study these resonances in the D 2 line of Rb in a room temperature vapor cell, and demonstrate a width of for the third-order rotation. The physical basis for the observed resonances is that optical pumping results in a simplified ΛV-type level structure with differential dressing of the levels by the control laser , which is why the control power has to be sufficiently high for each resonance to appear. This explanation is borne out by a density-matrix analysis of the system. The dispersive lineshape and subnatural width of the resonance lends itself naturally to applications such as laser locking to atomic transitions and precision measurements.

arXiv:1310.7330•Europhysics Letters (EPL)•May 1, 2014•4 citations

Phase-modulation laser spectroscopy

Axel Schenzle, Ralph G. DeVoe, Richard G. Brewer

A novel phase-modulation technique which permits subkilohertz-laser stability and new levels of precision in laser spectroscopy was reported recently. For spectroscopy, the basic arrangement consists of a combination of an optical pump and a probe field which is phase modulated. The pump prepares the atomic sample by burning a narrow hole within the atom's inhomogeneous line shape, and the probe beam samples the prepared hole when its modulation sidebands are swept into resonance. Off resonance, the probe is balanced as pairs of sidebands produce heterodyne beat signals of opposite phase which just cancel. On resonance, the balance is upset and yields a nonvanishing beat signal with a Lorentzian absorption or dispersion line shape and with residual noise approaching the shot noise limit. Here we investigate the theory of phase-modulation spectroscopy. We treat the nonlinear response of an atomic two-level quantum system subject to an intense pump and a weak copropagating or counterpropagating phase-modulated probe beam. The density-matrix equations of motion are solved by a Laplace-transform method and by the novel use of a translation operator which allows the infinite hierarchy of coupled equations to close. A solution equivalent to the rate-equation result is developed and coherence corrections are found which predict new resonances that have just been detected in this laboratory. The delayed pump-probe technique encountered in solid-state laser spectroscopy is analyzed in this context for two- and three-level quantum systems. The response of a Fabry-Perot cavity to a phase-modulated light wave is examined also and reveals an unexpected absorption feature.

Physical Review A•May 1, 1982•88 citations
Recent experiments have shown that optical pumping can produce line shapes with subnatural structure, and that this structure could prove to be useful for extracting oscillator strengths. A key question, however, regarding the optical-pumping technique's potential usefulness is how well it allows the determination of resonance line center. In the present paper we address this question theoretically by considering laser optical pumping and probing of an atomic beam. From the analysis (i) we find that depending on laser polarization the optical-pumping subnatural feature is either a dip or a signal enhancement, (ii) we derive the rigorously correct formula relating the dip width to the transition oscillator strength for an alkali-like atom exhibiting a homogeneous line shape, and (iii) we show that, compared to shot-noise-limited laser-induced fluorescence, the optical-pumping technique of signal enhancement is capable of a 15% improvement in the ability to find resonance line center.
The technique of optical pumping dips has been employed to generate subnatural structure in a 87Rb^{87}\mathrm{Rb}87Rb D1{D}_{1}D1​ line (natural width 5.6 MHz). Structure as narrow as 1.4 MHz was observed. These experiments represent the first observation of subnatural spectral structure generated without requiring atomic coherence. Additionally, line shapes observed in these studies may be analyzed to yield transition dipole moments without requiring internal standards or an absolute calibration of fluorescence collection efficiency in the experimental apparatus.
The detection of optical resonances by observation of the fluorescence light emitted from a fast atomic beam of Na interacting with a collinear laser beam is limited in sensitivity by optical pumping processes. In the experiment reported here, we take advantage of the optical pumping by using a second collinear laser beam, achieving then a gain in fluorescence signal. The effects of the lasers power and polarization on line shapes have been studied in the single laser excitation case as well as in the two laser beams one.
The ground electronic state of even such simple atoms as those of alkali elements has the set of sublevels. These sublevels are hyperfine (HF) components and magnetic sublevels. The collisions with particles of nonmagnetic buffer gas or even with walls (when walls have proper coating) do not mix practically the populations of ground state HF sublevels, if the orbital moment of electrons in the ground state is equal to zero. Due to this reason these sublevels may be extremely long lived. Because of this, for instance, the so-called effects of optical orientation and optical pumping are apparent in atoms of alkali metals. The radiation can pump practically all the atoms (with which there is effective interaction) to a single HF component. In a situation in which optical pumping is a minor effect, the monochromatic absorption line consists of separate lines corresponding to intra-atomic transitions. The optical pumping is not significant, for example, if the radiation intensity is so low that now pumping between HF sublevels occurs in the time it takes the atom to traverse the light beam. Under the conditions of optical pumping and when other nonlinear effects are present, the absorption line profile can undergo considerable alteration. Many theoretical and experimental investigations have been done in the laser spectroscopy of resonant transitions of atoms (atoms of alkali metals) under the conditions of optical pumping within ground state HF structure. A characteristic feature of all such investigations is the velocity-selective excitation of absorbing atoms. Also, as a rule, the value of HF splitting is not very big in comparison to Doppler broadening in these experiments. Under such conditions, the absorption spectra consists of Doppler- broadened lines with nonlinear resonances, which emerge when two fields of different frequencies or different propagation directions are employed. When only one monochromatic traveling wave is employed, optical pumping leads to formation of a single smooth absorption line occupying a position between the resonant transitions frequencies associated with HF components. As HF splitting grows, the line profile remains smooth, its width is approximately equal to the size of the HF splitting. The strength of the optical pumping from one ground state HF component to another is greater for greater HF splitting in comparison to the Doppler width. In this regard, Cs and Rb are the most typical of the alkali atoms (the HF splitting exceeds the Doppler width by a factor close to 20). This is the qualitative picture of the absorption line profile (particularly for a monochromatic radiation) under the conditions of optical pumping between the HF sublevels of the electronic ground state, this qualitative picture had formed by now.
We demonstrate extremely narrow resonances for polarization rotation in an atomic vapor. The resonances are created using a strong control laser on the same transition, which polarizes the atoms due to optical pumping among the magnetic sublevels. As the power in the control laser is increased, successively higher-order nested polarization-rotation resonances are created, with progressively narrower linewidths. We study these resonances in the D 2 line of Rb in a room temperature vapor cell, and demonstrate a width of for the third-order rotation. The physical basis for the observed resonances is that optical pumping results in a simplified ΛV-type level structure with differential dressing of the levels by the control laser , which is why the control power has to be sufficiently high for each resonance to appear. This explanation is borne out by a density-matrix analysis of the system. The dispersive lineshape and subnatural width of the resonance lends itself naturally to applications such as laser locking to atomic transitions and precision measurements.
A novel phase-modulation technique which permits subkilohertz-laser stability and new levels of precision in laser spectroscopy was reported recently. For spectroscopy, the basic arrangement consists of a combination of an optical pump and a probe field which is phase modulated. The pump prepares the atomic sample by burning a narrow hole within the atom's inhomogeneous line shape, and the probe beam samples the prepared hole when its modulation sidebands are swept into resonance. Off resonance, the probe is balanced as pairs of sidebands produce heterodyne beat signals of opposite phase which just cancel. On resonance, the balance is upset and yields a nonvanishing beat signal with a Lorentzian absorption or dispersion line shape and with residual noise approaching the shot noise limit. Here we investigate the theory of phase-modulation spectroscopy. We treat the nonlinear response of an atomic two-level quantum system subject to an intense pump and a weak copropagating or counterpropagating phase-modulated probe beam. The density-matrix equations of motion are solved by a Laplace-transform method and by the novel use of a translation operator which allows the infinite hierarchy of coupled equations to close. A solution equivalent to the rate-equation result is developed and coherence corrections are found which predict new resonances that have just been detected in this laboratory. The delayed pump-probe technique encountered in solid-state laser spectroscopy is analyzed in this context for two- and three-level quantum systems. The response of a Fabry-Perot cavity to a phase-modulated light wave is examined also and reveals an unexpected absorption feature.