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

arXiv:1707.02947 · Physical Review A

Two-temperature momentum distribution in a thulium magneto-optical trap

Елена Сергеевна Калганова, Прудников Олег Николаевич, Gulnara A. Vishnyakova, Artem A. Golovizin, Dmitry O. Tregubov, Денис Дмитриевич Сукачев, Ksenia Yu. Khabarova, В. Н. Сорокин, N. Kolachevsky

Published Sep 29, 2017• 19 citations
arXivHTMLPDF

Abstract

Second-stage laser cooling of thulium atoms at the 530.7 nm transition with a natural linewidth of 350 kHz offers an interesting possibility to study different regimes of a magneto-optical trap (MOT). The intermediate value of the spectral linewidth of the cooling transition allows the observation of three distinct regimes depending on the intensity and detuning of the cooling beams, namely, the ``bowl-shaped'' regime when light pressure force competes with gravity, the ``double structure'' regime with interplay between the Doppler and polarization-gradient (sub-Doppler) cooling, and the ``symmetric'' regime when Doppler cooling dominates over sub-Doppler cooling and gravity. The polarization-gradient cooling manifests itself by a two-temperature momentum distribution of atoms resulting in a double-structure of the spatial MOT profile consisting of a cold central fraction surrounded by a hot halo. We studied the double structure regime at different saturation parameters and compared observations with calculations based on semiclassical and quantum approaches. The quantum treatment adequately reproduces experimental results if the MOT magnetic field is properly taken into account.

DOI
10.1103/physreva.96.033418

Related papers

Laser cooling of thulium atoms

Денис Дмитриевич Сукачев, K. Chebakov, А. В. Соколов +3 more

We demonstrated laser cooling and trapping of thulium atoms at sub-Doppler temperatures in a magneto-optical trap (MOT). Up to 3 × 10 6 thulium atoms were trapped in the MOT at temperatures down to 25(5) μK which is approximately 10 times lower than the Doppler limit. The lifetime of atoms in the MOT varied between 0.3–1.5 s and was restricted mostly by optical leaks from the upper cooling level. The lower limit for the leaking rate was estimated to be 22(6) s −1 . Due to a big magnetic moment of Tm atoms, a part of them were trapped in a magnetic trap from the quadrupole field of the MOT. We observed about 3 × 10 4 purely magnetically trapped atoms at temperature of 25 μK with a lifetime in the trap of 0.5 s. Also we set up a “dark” MOT consisting of six crossed hollow beams which increased the number of trapped atoms by a factor of 5 leading to 1.5 × 10 7 atoms at the expense of higher temperature.

Optics and Spectroscopy•Oct 1, 2011•6 citations

Sub-doppler laser cooling of thulium atoms in a magneto-optical trap

D. Sukachev, A. Sokolov, K. Chebakov +3 more

Sub-Doppler laser cooling in a magneto-optical trap for thulium atoms at a wavelength of 410.6 nm has been experimentally studied. Without any dedicated molasses period of sub-Doppler cooling, the cloud of 3 × 106 atoms at a temperature of 25(5) μK was observed. The measured temperature is significantly lower than the Doppler limit of 240 μK for the cooling transition at 410.6 nm. The high efficiency of the sub-Doppler cooling process is due to a near-degeneracy of the Landé g-factors of the lower 4f 136s 2 (J = 7/2) and the upper 4f 125d 3/26s 2 (J = 9/2) cooling levels.

arXiv:1012.5433•Journal of Experimental and Theoretical Physics Letters•Nov 1, 2010•23 citations

Investigation of a two level Atom in a Magneto-optical Trap

F. Y. Loo, Anders Brusch, S. SANGE +4 more

Magnesium atoms are cooled in a magneto-optical trap (MOT) using the 3s(2 1)S(0) --> 3s3p P-1(1) resonance transition. Magnesium is a simple atom which offers a unique possibility for comparison to the Doppler theory of laser cooling. We measure trap parameters as a function of laser-intensity, -detuning and magnetic field gradient. We find the main features well accounted for by Doppler theory, but temperature measurements gave significant higher values than predicted by the Doppler theory. We also observe radiation pressure effects within the MOT that limit the maximum achievable density. Comparing our results to predictions by models in the literature shows a good agreement. Recently we have improved our set-up and now trap about 150 x 10(6) atoms.

•Jan 1, 2004•27 citations

Investigations of a two-level atom in a magneto-optical trap using magnesium

F. Y. Loo, Anders Brusch, Sébastien Sauge +4 more

Magnesium atoms are cooled in a magneto-optical trap (MOT) using the 3s2 S0 → 3s3p P1 resonance transition. Magnesium is a simple atom which offers a unique possibility for comparison to the Doppler theory of laser cooling. We measure trap parameters as a function of laser-intensity, -detuning and magnetic field gradient. We find the main features well accounted for by Doppler theory, but temperature measurements gave significant higher values than predicted by the Doppler theory. We also observe radiation pressure effects within the MOT that limit the maximum achievable density. Comparing our results to predictions by models in the literature shows a good agreement. Recently we have improved our set-up and now trap about 150 × 106 atoms.

Journal of Optics B Quantum and Semiclassical Optics•Nov 7, 2003•3 citations

Capture of Thulium Atoms into a Magneto-Optical Trap and Their Detection Using the 530-nm Transition

Daniil I. Provorchenko, A. A. Dvurechenskii, B. A. Bessmertnykh +4 more

The efficient capture of thulium atoms from an atomic beam into a magneto-optical trap at the spectrally narrow 530-nm transition with a natural linewidth of 350 kHz, avoiding the primary cooling stage that is standard in many experiments, has been demonstrated. To optimize the capture parameters, a machine learning method with automated control of the experimental setup and feedback has been used, which has made it possible to achieve more than 75% capture efficiency compared to the previously used configuration. In addition, the number of atoms has been measured using 530-nm probe radiation with the ability to achieve signal-to-noise levels comparable to those obtained with fluorescence detection on the strong 410-nm transition. This significantly reduces the requirements for the 410-nm laser system, which was previously used for primary cooling and detection of atoms, simplifying the experimental setup and paving the way toward transportable thulium optical clocks.

Journal of Experimental and Theoretical Physics Letters•Jun 1, 2026•0 citations

Two-stage laser cooling and optical trapping of thulium atoms

Gulnara A. Vishnyakova, Елена Сергеевна Калганова, Денис Дмитриевич Сукачев +5 more

We propose to use the magnetic-dipole transition at coupling two ground state fine-structure components of thulium (Tm), as a 'clock transition' in optical clocks. We have demonstrated first stage laser cooling of Tm atoms down to a temperature of 25 K using a strong transition at and we have also shown preliminary results for second stage cooling using a weaker transition at (natural linewidth γ G = 350 kHz). Laser cooled atoms have been trapped in an optical dipole trap and in a 1D optical lattice operating near 532 nm.

Laser Physics•Jun 13, 2014•19 citations
Second-stage laser cooling of thulium atoms at the 530.7 nm transition with a natural linewidth of 350 kHz offers an interesting possibility to study different regimes of a magneto-optical trap (MOT). The intermediate value of the spectral linewidth of the cooling transition allows the observation of three distinct regimes depending on the intensity and detuning of the cooling beams, namely, the bowl-shaped'' regime when light pressure force competes with gravity, the double structure'' regime with interplay between the Doppler and polarization-gradient (sub-Doppler) cooling, and the ``symmetric'' regime when Doppler cooling dominates over sub-Doppler cooling and gravity. The polarization-gradient cooling manifests itself by a two-temperature momentum distribution of atoms resulting in a double-structure of the spatial MOT profile consisting of a cold central fraction surrounded by a hot halo. We studied the double structure regime at different saturation parameters and compared observations with calculations based on semiclassical and quantum approaches. The quantum treatment adequately reproduces experimental results if the MOT magnetic field is properly taken into account.
We demonstrated laser cooling and trapping of thulium atoms at sub-Doppler temperatures in a magneto-optical trap (MOT). Up to 3 × 10 6 thulium atoms were trapped in the MOT at temperatures down to 25(5) μK which is approximately 10 times lower than the Doppler limit. The lifetime of atoms in the MOT varied between 0.3–1.5 s and was restricted mostly by optical leaks from the upper cooling level. The lower limit for the leaking rate was estimated to be 22(6) s −1 . Due to a big magnetic moment of Tm atoms, a part of them were trapped in a magnetic trap from the quadrupole field of the MOT. We observed about 3 × 10 4 purely magnetically trapped atoms at temperature of 25 μK with a lifetime in the trap of 0.5 s. Also we set up a “dark” MOT consisting of six crossed hollow beams which increased the number of trapped atoms by a factor of 5 leading to 1.5 × 10 7 atoms at the expense of higher temperature.
Sub-Doppler laser cooling in a magneto-optical trap for thulium atoms at a wavelength of 410.6 nm has been experimentally studied. Without any dedicated molasses period of sub-Doppler cooling, the cloud of 3 × 106 atoms at a temperature of 25(5) μK was observed. The measured temperature is significantly lower than the Doppler limit of 240 μK for the cooling transition at 410.6 nm. The high efficiency of the sub-Doppler cooling process is due to a near-degeneracy of the Landé g-factors of the lower 4f 136s 2 (J = 7/2) and the upper 4f 125d 3/26s 2 (J = 9/2) cooling levels.
Magnesium atoms are cooled in a magneto-optical trap (MOT) using the 3s(2 1)S(0) --> 3s3p P-1(1) resonance transition. Magnesium is a simple atom which offers a unique possibility for comparison to the Doppler theory of laser cooling. We measure trap parameters as a function of laser-intensity, -detuning and magnetic field gradient. We find the main features well accounted for by Doppler theory, but temperature measurements gave significant higher values than predicted by the Doppler theory. We also observe radiation pressure effects within the MOT that limit the maximum achievable density. Comparing our results to predictions by models in the literature shows a good agreement. Recently we have improved our set-up and now trap about 150 x 10(6) atoms.
Magnesium atoms are cooled in a magneto-optical trap (MOT) using the 3s2 S0 → 3s3p P1 resonance transition. Magnesium is a simple atom which offers a unique possibility for comparison to the Doppler theory of laser cooling. We measure trap parameters as a function of laser-intensity, -detuning and magnetic field gradient. We find the main features well accounted for by Doppler theory, but temperature measurements gave significant higher values than predicted by the Doppler theory. We also observe radiation pressure effects within the MOT that limit the maximum achievable density. Comparing our results to predictions by models in the literature shows a good agreement. Recently we have improved our set-up and now trap about 150 × 106 atoms.
The efficient capture of thulium atoms from an atomic beam into a magneto-optical trap at the spectrally narrow 530-nm transition with a natural linewidth of 350 kHz, avoiding the primary cooling stage that is standard in many experiments, has been demonstrated. To optimize the capture parameters, a machine learning method with automated control of the experimental setup and feedback has been used, which has made it possible to achieve more than 75% capture efficiency compared to the previously used configuration. In addition, the number of atoms has been measured using 530-nm probe radiation with the ability to achieve signal-to-noise levels comparable to those obtained with fluorescence detection on the strong 410-nm transition. This significantly reduces the requirements for the 410-nm laser system, which was previously used for primary cooling and detection of atoms, simplifying the experimental setup and paving the way toward transportable thulium optical clocks.
We propose to use the magnetic-dipole transition at coupling two ground state fine-structure components of thulium (Tm), as a 'clock transition' in optical clocks. We have demonstrated first stage laser cooling of Tm atoms down to a temperature of 25 K using a strong transition at and we have also shown preliminary results for second stage cooling using a weaker transition at (natural linewidth γ G = 350 kHz). Laser cooled atoms have been trapped in an optical dipole trap and in a 1D optical lattice operating near 532 nm.