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 Letters

Subnatural coherence effects in saturation spectroscopy using a single traveling wave

Graciela Bertuccelli, Giovanni Giusfredi, N. Beverini, Mara Galli, M. Inguscio, F. Strumia

Published Jun 1, 1985• 14 citations
Publisher

Abstract

We have performed zero-field level-crossing resonance measurements (nonlinear Hanle effect) in a metastable Ca atomic beam. By saturating the optical transitions (3)P(1,2) ? (3)S(1), for which the radiative linewidth is 10.5 MHz, we have recorded resonances corresponding to widths of about 31 kHz. The effect has been investigated as a function of the saturating-radiation intensity. The frequency jitter of the laser used in the measurements is about 40 times wider than the recorded widths.

DOI
10.1364/ol.10.000270

Related papers

Ramsey fringes in the nonlinear Hanle effect in a metastable atomic beam

Graciela Bertuccelli, N. Beverini, Mara Galli +2 more

Evidence of coherence effects has been observed in the Zeeman sublevels by means of nonlinear level crossing in a metastable Ca beam with resonance width 3 orders of magnitude less than the radiative linewidth of the investigated transitions. By using two separate traveling waves, Ramsey-like fringes have been observed. The final measured widths are determined by the transit time, are weakly dependent on the magnetic-field inhomogeneities, and are independent of the natural width of the optical transitions and the laser bandwidth.

Optics Letters•Jun 1, 1986•6 citations

Observation of subnatural fluorescence linewidths due to coherent stabilization of quantum fluctuations

Daniel J. Gauthier, Yifu Zhu, THOMAS W. MOSSBERG

Recently, Narducci et al.1 studied V-configuration three-level atoms and predicted that quantum fluctuations associated with a "strong" optical transition driven by a coherent field can be stabilized through excitation of a coupled "weak" transition. This stabilization is manifest in a narrowing, to subnatural values, of the fluorescence linewidths associated with the strong transition as the weak transition is driven more and more strongly. We have experimentally investigated this problem and provide the first demonstration of the effect. In the experiment, a beam of Ba atoms was intercepted by two copropagating cw laser beams. One of the beams, of Rabi frequency Ω1, was tuned into resonance with the strong, 553.5 nm, 1S0→3P1 transition, while the other beam, of Rabi frequency Ω2, was tuned into resonance with the weak, 791.1 nm, 1S0→3P1 transition. The fluorescence spectrum of the strong transition was recorded for the case when Ω1≈35 MHz and Q2≈45 MHz and, it was found that the spectrum was three-peaked. Most interestingly, the measured linewidth (FWHM) for the central peak was 16 MHz, or 2 MHz less than the 18 MHz natural width of the strong transition even before the substantial instrumental broadening (≈8 MHz) of the peak was deconvolved.

Annual Meeting Optical Society of America•Jan 1, 1990•0 citations

Coherent effects on the Zeeman sublevels of hyperfine states at the D1and D2lines of Rb

G. Alzetta, S. Cartaleva, Yordanka V. Dancheva +4 more

Subnatural-width resonances due to coherent effects in optical pumping at hyperfine (hf) transitions of Rb are investigated using a linearly or circularly polarized single-frequency diode laser beam. The sign and amplitude of the resonances in the fluorescence are measured by scanning the laser frequency over the hf transitions of the Rb D 1 and D 2 lines. The fluorescence perpendicular to the laser beam is detected as a function of magnetic field parallel to the beam propagation and scanned around zero value. In the case of linear polarization of the field, dark resonances are observed for hf transitions with F g → F e = F g -1 and F g → F e = F g , and bright resonances are observed for transitions with F g → F e = F g + 1. This is in agreement with the recently developed theories. For all (except F g = 2→ F e = 3, 85 Rb, D 1 line) hf transitions the sign of the resonances reverses when the polarization of the field changes to circular. The amplitudes of the resonances correspond to the probability of the hf transitions and to the calculated loss rate of the population to the ground hf level not excited by the laser field. The observed narrow resonances (FWHM: few tens of kHz) and their sensitivity to weak magnetic fields are interesting for high-resolution spectroscopy and for development of simple and precise magnetometers.

Journal of Optics B Quantum and Semiclassical Optics•May 29, 2001•45 citations

Level-crossing resonances on open atomic transitions in a buffered Cs vapor cell: Linewidth narrowing, high contrast, and atomic magnetometry applications

Denis V. Brazhnikov, V. I. Vishnyakov, Andrei Goncharov +3 more

The ground-state Hanle effect (GSHE) in alkali-metal atomic vapor using a single circularly polarized light wave underlies one of the most reliable and simple techniques of modern atomic magnetometry. This effect causes a narrow (subnatural-width) resonance in the light wave intensity passing through the vapor cell. The GSHE-based sensors typically operate in the so-called spin-exchange relaxation-free (SERF) regime to reduce the resonance linewidth. However, this regime requires a relatively high temperature of vapors (approximately equal to $150{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$), leading to high heat release and power consumption of the sensor head. In addition, without applying special measures, the SERF regime significantly limits the dynamic range of measurements. Here we study a pump-probe scheme involving a single elliptically polarized light wave and a polarimetric detection technique. The wave is in resonance with two adjacent optical transitions in the cesium ${D}_{1}$ line ($\ensuremath{\lambda}\phantom{\rule{0.16em}{0ex}}\ensuremath{\approx}\phantom{\rule{0.16em}{0ex}}894.5$ nm) due to their overlap in the presence of a buffer gas (130 Torr neon). Using a small ($V\ensuremath{\approx}0.1\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{3}$) glass vapor cell, we demonstrate the possibility to observe subnatural-width resonances with a high contrast-to-width ratio (up to 45%/mG) in low-temperature ($60{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$) operation due to strong light-induced circular dichroism in the medium. Based on the $\mathrm{\ensuremath{\Lambda}}$ scheme of atomic energy levels, we obtain explicit analytical expressions for the shape of the resonance line. The model reveals a linewidth narrowing effect due to openness of the level scheme. The observed bright features are unusual for magneto-optical atomic spectroscopy as openness is commonly considered to be an undesirable effect that degrades resonance characteristics. Measuring the noise voltage, we estimate the sensitivity of the magnetic-field measurements to be 1.8 $\mathrm{pT}/\sqrt{\mathrm{Hz}}$ with a sensitivity of 60 $\mathrm{fT}/\sqrt{\mathrm{Hz}}$ in the photon-shot-noise limit. In general, the results contribute to the theory of GSHE resonances and also can be applied to development of a low-temperature high-sensitivity miniaturized magnetic-field sensor with an extended dynamic range.

arXiv:2205.04925•Physical Review A•Jul 26, 2022•12 citations

Optical Hanle effect

V.Paul Kaftandjian, Christian Delsart, J. Keller

The optical Hanle effect (light-shift-induced zero-field level crossing) has been investigated theoretically and experimentally. In the case of a $J=0\ensuremath{\rightarrow}1\ensuremath{\rightarrow}0$ three-level system and of a $J=0\ensuremath{\rightarrow}1$ two-level system, the resonance line shape has been obtained using a nonlinear-response-function method. Approximate expressions, valid under the conditions for the observation of light shifts, are obtained and compared with exact calculations as well as with the corresponding expression for the magnetic Hanle effect. As concerns the weak laser beam which produces the coherent excitation of atomic substates, we have calculated the linear response in the limiting case of monochromatic and of broad-band excitation. The experimental investigation has been performed for the Ba resonance line using two cw dye lasers at $\ensuremath{\lambda}=5535$ \AA{} and an atomic beam. The absorption- and dispersion-shaped level crossing resonances have been observed, for narrow- and broad-band excitation, by varying the power of the strong nonresonant laser beam. We have checked that the line shapes are only dependent upon the reduced variable $\frac{{P}_{L}}{\ensuremath{\delta}}$ (${P}_{L}$; beam power; $\ensuremath{\delta}$: frequency detuning). Using the theoretical expressions, we have tried to fit the experimental curves. Provided that the Gaussian distribution of the beams is taken into account, we have obtained a good agreement between theory and experiment for the whole set of experimental data.

Physical Review A•Mar 1, 1981•13 citations

Saturation Behavior of a Doppler-Broadened Transition Involving Levels with Closely Spaced Structure

H. Schlossberg, Ali Javan

The nonlinear absorption or gain characteristics of an optical-frequency, Doppler-broadened atomic resonance involving levels with closely spaced structure are analyzed. The level structures are assumed to be resolved with respect to their natural widths, but not necessarily with respect to the Doppler width at the optical transition. The radiation field consists of two closely spaced monochromatic frequencies lying within the Doppler width of the resonance. This type of radiation field may be obtained, for example, from a laser operating in two of its Fabry-Perot resonator modes. It is shown that, because of saturation of level populations and double-quantum Raman transitions between levels, appreciable nonlinear coupling takes place between the two fields. This coupling shows a resonance behavior when the frequency separation of the two applied fields becomes equal to the frequency splitting between two of the components which form either level structure. The width of this resonance is determined entirely by the natural widths of these two level components and not by the Doppler width of the optical transition or the natural width of other level components. When such a resonance occurs, the over-all gain or attenuation characteristics of the atomic resonance change drastically. In practice the frequency spacing of the fields may be kept constant while the level structures are tuned, e.g., magnetically. The effects are analyzed for cases of running-wave and standing-wave radiation fields. The use of this effect in precise determination of level structures as well as mode or transition coupling of a gas laser is discussed. Portions of the analysis are applicable to resonances with more general forms of inhomogeneous broadening.

Physical Review•Oct 7, 1966•185 citations
We have performed zero-field level-crossing resonance measurements (nonlinear Hanle effect) in a metastable Ca atomic beam. By saturating the optical transitions (3)P(1,2) ? (3)S(1), for which the radiative linewidth is 10.5 MHz, we have recorded resonances corresponding to widths of about 31 kHz. The effect has been investigated as a function of the saturating-radiation intensity. The frequency jitter of the laser used in the measurements is about 40 times wider than the recorded widths.
Evidence of coherence effects has been observed in the Zeeman sublevels by means of nonlinear level crossing in a metastable Ca beam with resonance width 3 orders of magnitude less than the radiative linewidth of the investigated transitions. By using two separate traveling waves, Ramsey-like fringes have been observed. The final measured widths are determined by the transit time, are weakly dependent on the magnetic-field inhomogeneities, and are independent of the natural width of the optical transitions and the laser bandwidth.
Recently, Narducci et al.1 studied V-configuration three-level atoms and predicted that quantum fluctuations associated with a "strong" optical transition driven by a coherent field can be stabilized through excitation of a coupled "weak" transition. This stabilization is manifest in a narrowing, to subnatural values, of the fluorescence linewidths associated with the strong transition as the weak transition is driven more and more strongly. We have experimentally investigated this problem and provide the first demonstration of the effect. In the experiment, a beam of Ba atoms was intercepted by two copropagating cw laser beams. One of the beams, of Rabi frequency Ω1, was tuned into resonance with the strong, 553.5 nm, 1S0→3P1 transition, while the other beam, of Rabi frequency Ω2, was tuned into resonance with the weak, 791.1 nm, 1S0→3P1 transition. The fluorescence spectrum of the strong transition was recorded for the case when Ω1≈35 MHz and Q2≈45 MHz and, it was found that the spectrum was three-peaked. Most interestingly, the measured linewidth (FWHM) for the central peak was 16 MHz, or 2 MHz less than the 18 MHz natural width of the strong transition even before the substantial instrumental broadening (≈8 MHz) of the peak was deconvolved.
Subnatural-width resonances due to coherent effects in optical pumping at hyperfine (hf) transitions of Rb are investigated using a linearly or circularly polarized single-frequency diode laser beam. The sign and amplitude of the resonances in the fluorescence are measured by scanning the laser frequency over the hf transitions of the Rb D 1 and D 2 lines. The fluorescence perpendicular to the laser beam is detected as a function of magnetic field parallel to the beam propagation and scanned around zero value. In the case of linear polarization of the field, dark resonances are observed for hf transitions with F g → F e = F g -1 and F g → F e = F g , and bright resonances are observed for transitions with F g → F e = F g + 1. This is in agreement with the recently developed theories. For all (except F g = 2→ F e = 3, 85 Rb, D 1 line) hf transitions the sign of the resonances reverses when the polarization of the field changes to circular. The amplitudes of the resonances correspond to the probability of the hf transitions and to the calculated loss rate of the population to the ground hf level not excited by the laser field. The observed narrow resonances (FWHM: few tens of kHz) and their sensitivity to weak magnetic fields are interesting for high-resolution spectroscopy and for development of simple and precise magnetometers.
The ground-state Hanle effect (GSHE) in alkali-metal atomic vapor using a single circularly polarized light wave underlies one of the most reliable and simple techniques of modern atomic magnetometry. This effect causes a narrow (subnatural-width) resonance in the light wave intensity passing through the vapor cell. The GSHE-based sensors typically operate in the so-called spin-exchange relaxation-free (SERF) regime to reduce the resonance linewidth. However, this regime requires a relatively high temperature of vapors (approximately equal to $150{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$), leading to high heat release and power consumption of the sensor head. In addition, without applying special measures, the SERF regime significantly limits the dynamic range of measurements. Here we study a pump-probe scheme involving a single elliptically polarized light wave and a polarimetric detection technique. The wave is in resonance with two adjacent optical transitions in the cesium D1{D}_{1}D1​ line ($\ensuremath{\lambda}\phantom{\rule{0.16em}{0ex}}\ensuremath{\approx}\phantom{\rule{0.16em}{0ex}}894.5$ nm) due to their overlap in the presence of a buffer gas (130 Torr neon). Using a small ($V\ensuremath{\approx}0.1\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{3}$) glass vapor cell, we demonstrate the possibility to observe subnatural-width resonances with a high contrast-to-width ratio (up to 45%/mG) in low-temperature ($60{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$) operation due to strong light-induced circular dichroism in the medium. Based on the $\mathrm{\ensuremath{\Lambda}}$ scheme of atomic energy levels, we obtain explicit analytical expressions for the shape of the resonance line. The model reveals a linewidth narrowing effect due to openness of the level scheme. The observed bright features are unusual for magneto-optical atomic spectroscopy as openness is commonly considered to be an undesirable effect that degrades resonance characteristics. Measuring the noise voltage, we estimate the sensitivity of the magnetic-field measurements to be 1.8 pT/Hz\mathrm{pT}/\sqrt{\mathrm{Hz}}pT/Hz​ with a sensitivity of 60 fT/Hz\mathrm{fT}/\sqrt{\mathrm{Hz}}fT/Hz​ in the photon-shot-noise limit. In general, the results contribute to the theory of GSHE resonances and also can be applied to development of a low-temperature high-sensitivity miniaturized magnetic-field sensor with an extended dynamic range.
The optical Hanle effect (light-shift-induced zero-field level crossing) has been investigated theoretically and experimentally. In the case of a $J=0\ensuremath{\rightarrow}1\ensuremath{\rightarrow}0$ three-level system and of a $J=0\ensuremath{\rightarrow}1$ two-level system, the resonance line shape has been obtained using a nonlinear-response-function method. Approximate expressions, valid under the conditions for the observation of light shifts, are obtained and compared with exact calculations as well as with the corresponding expression for the magnetic Hanle effect. As concerns the weak laser beam which produces the coherent excitation of atomic substates, we have calculated the linear response in the limiting case of monochromatic and of broad-band excitation. The experimental investigation has been performed for the Ba resonance line using two cw dye lasers at $\ensuremath{\lambda}=5535$ \AA{} and an atomic beam. The absorption- and dispersion-shaped level crossing resonances have been observed, for narrow- and broad-band excitation, by varying the power of the strong nonresonant laser beam. We have checked that the line shapes are only dependent upon the reduced variable $\frac{{P}_{L}}{\ensuremath{\delta}}$ (PL{P}_{L}PL​; beam power; $\ensuremath{\delta}$: frequency detuning). Using the theoretical expressions, we have tried to fit the experimental curves. Provided that the Gaussian distribution of the beams is taken into account, we have obtained a good agreement between theory and experiment for the whole set of experimental data.
The nonlinear absorption or gain characteristics of an optical-frequency, Doppler-broadened atomic resonance involving levels with closely spaced structure are analyzed. The level structures are assumed to be resolved with respect to their natural widths, but not necessarily with respect to the Doppler width at the optical transition. The radiation field consists of two closely spaced monochromatic frequencies lying within the Doppler width of the resonance. This type of radiation field may be obtained, for example, from a laser operating in two of its Fabry-Perot resonator modes. It is shown that, because of saturation of level populations and double-quantum Raman transitions between levels, appreciable nonlinear coupling takes place between the two fields. This coupling shows a resonance behavior when the frequency separation of the two applied fields becomes equal to the frequency splitting between two of the components which form either level structure. The width of this resonance is determined entirely by the natural widths of these two level components and not by the Doppler width of the optical transition or the natural width of other level components. When such a resonance occurs, the over-all gain or attenuation characteristics of the atomic resonance change drastically. In practice the frequency spacing of the fields may be kept constant while the level structures are tuned, e.g., magnetically. The effects are analyzed for cases of running-wave and standing-wave radiation fields. The use of this effect in precise determination of level structures as well as mode or transition coupling of a gas laser is discussed. Portions of the analysis are applicable to resonances with more general forms of inhomogeneous broadening.