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

Chinese Optics Letters

Magneto-optical isotope enrichment of potassium-40 with transverse cooling

Shangjin Li, Zixuan Zeng, Bo Yan

Published Jan 1, 2024• 0 citations
Publisher

Abstract

Isotope shifts among different isotopes can be effectively addressed using narrow-linewidth lasers, facilitating laser isotope separation and achieving significant enrichment at a single stage.The separation of potassium isotopes, employing optical pumping and magnetic deflection, has proven to be efficient.To further improve the enrichment of 40 K, we introduce 2D transverse cooling to minimize the divergence angle.Through this modification, we demonstrate enrichment of 40 K, elevating it from 0.012% to 12%-20%.This represents an enrichment increase by three orders of magnitude, surpassing our previous result by one order.Our method is particularly well-suited for isotope enrichment of elements with extremely low abundance.

DOI
10.3788/col202422.070201

Related papers

Isotope separation of Potassium with a magneto-optical combined method

Zixuan Zeng, Shangjin Li, Bo Yan

Due to the similar physical and chemical properties, isotopes are usually hard to separate. On the other hand, the isotope shifts are very well separated in a high-resolution spectrum, making them possible to be addressed individually by lasers, thus separated. Here we report such an isotope separation experiment with Potassium atoms. The isotopes are independently optical pumped to the desired spin states, and then separated with a Stern-Gerlach scheme. A micro-capillary oven is used to collimate the atomic beam, and a Halbach-type magnet array is used to deflect the desired atoms. Finally, the 40K is enriched by two orders of magnitude. This magneto-optical combined method provides an effective way to separate isotopes and can be extended to other elements if the relevant optical pumping scheme is feasible.

arXiv:2111.10918•Frontiers of Physics•Nov 19, 2021•2 citations

LASER ISOTOPE ENRICHMENT VIA MAGNETIC DEFLECTION OF OPTICALLY POLARIZED ATOMIC BEAM

Xiwen Zhu, 中国科学院武汉物理研究所

We describe a novel method to enrich isotopes and isomers via magnetic deflection of optically polarized atomic beam. High electronic polarization with opposite signs for atoms of both isotopes respectively is achieved by selective optical pumping using lasers with different frequencies and polarizations and then the isotopes are enriched by deflecting the oppositely polarized isotopes along different directions by the inhomo-geneous magnetic field in the spin selective magnet. Separation selectivity and throughput are evaluated and the advantages, disadvantages and prospects of possible application of the present method are discussed in comparison with other existing methods. Experimental scheme with lithium or potassium is suggested.

Acta Physica Sinica•Jan 1, 1984•4 citations

Sub-Doppler laser cooling and magnetic trapping of natural-abundance fermionic potassium

Mateusz Bocheński, Mariusz Semczuk

Abstract We demonstrate the largest number of 40K atoms that has ever been cooled to deeply sub-Doppler temperatures in a single-chamber apparatus without using an enriched source of potassium. With gray molasses cooling on the D 1-line following a standard D 2-line magneto-optical trap, we obtain 3 × 10 5 atoms at 10(2) µK. We reach densities high enough to measure the temperature via absorption imaging using the time-of-flight method. We magnetically trap a mixture of m F = − 3 / 2 , − 5 / 2 and − 7 / 2 Zeeman states of the F = 7 / 2 hyperfine ground state confining 5 × 10 4 atoms with a lifetime of 0.6 s or ∼ 10 3 atoms with a lifetime of 2.8 s—depending on whether the temperature of the potassium dispensers was chosen to maximize the atom number or the lifetime. The background pressure-limited lifetime of 0.6 s is a reasonable starting point for proof-of-principle experiments with atoms and/or molecules in optical tweezers as well as for sympathetic cooling with another species if transport to a secondary chamber is implemented. Our results show that unenriched potassium can be used to optimize experimental setups containing 40K in the initial stages of their construction, which can effectively extend the lifetime of enriched sources. Moreover, the demonstration of sub-Doppler cooling and magnetic trapping of a relatively small number of potassium atoms might influence experiments with laser-cooled radioactive isotopes of potassium.

arXiv:2307.16469•Journal of Physics B Atomic Molecular and Optical Physics•Jan 23, 2024•1 citation

Laser isotope enrichment of lithium by magnetic deflection of a polarized atomic beam

Zhu Xiwen, Huang Gui-long, Mei Ganghua +1 more

The authors have succeeded in demonstrating laser isotope enrichment via magnetic deflection of a polarized atomic beam. By using a single dye laser with the frequency tuned to the two accidentally close transitions of the natural lithium (2 2 S 1/2 (F=1/2) to 2 2 P 3/2 for 6 Li and 2 2 S 1/2 (F=2) to 2 2 P 1 2/(F=1) for 7 Li), 6 Li and 7 Li atoms in a beam were positively and negatively polarized respectively. The 6 Li enrichment was achieved via magnetic deflection of the polarized beam through a hexapole magnet which focuses the positively polarized 6 Li atoms and defocuses the negatively polarized 7 Li atoms. The dependence of 7 Li polarization on laser intensity was experimentally examined, and the result was in good agreement with that calculated by rate equations. The abundance ratio of 6 Li to 7 Li was enhanced from 1 : 12.5 to about 1 : 3.1.

Journal of Physics B Atomic Molecular and Optical Physics•Aug 14, 1992•10 citations

Enhanced Loading of 40 K from Natural Abundance Potassium Source with a High Performance 2D + MOT

Jiang-Ling Yang, Yun Long, Wei-Wei Gao +3 more

40 K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low concentration (0.012%) of 40 K in natural abundance of potassium, most experiments use 4–10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4×10 6 cold 40 K atoms with the help of a high performance of two-dimensional magneto-optical trap (2D + MOT), which is almost three orders of magnitude greater than previous results without the 2D + MOT. The number of the 40 K atoms is sufficient for most ultra-cold 40 K experiments, and our approach provides an ideal alternative for the field.

Chinese Physics Letters•Mar 1, 2018•3 citations

Narrow-line magneto-optical trap of titanium atoms

Rowan Duim, Scott Eustice, Jackson Schrott +2 more

We realize narrow-linewidth magneto-optical traps of $^{46}$Ti, $^{48}$Ti and $^{50}$Ti atoms based on a 1040 nm-wavelength transition, cooling atoms to a minimum temperature in one dimension of $T_z=990(20)$ nK and a three-dimensional temperature of $T_\mathrm{3D}=1.28(7)$ $μ$K. Atoms are pre-cooled in a broad-line magneto-optical trap and then transferred with about 25% efficiency to the narrow-line trap. We operate the narrow-line trap in two stages over 85 ms. First, a single cooling beam, blue-detuned from the narrow-linewidth atomic resonance, optically pumps and traps the atoms on a two-dimensional surface where the Zeeman shift from the applied spherical quadrupole magnetic field brings the light nearly to resonance. Second, four additional beams, counter-propagating in the transverse directions, cool and compress the atoms in all dimensions. The high magnetic moment of the laser cooling state makes the dynamics of the narrow-line titanium trap similar to those of other magnetic atoms. We measure the lifetime of the excited state of the transition to be $τ=8.2(9)$ $μ$s, indicating a transition linewidth of $γ/2π=20(2)$ kHz, and also measure isotope shifts on the narrow-line transition. We use Stern-Gerlach separation on the ultracold Ti gas to measure the $m_J$-distribution in the narrow-line magneto-optical trap, finding over 98% of the atoms in the stretched spin state.

arXiv:2609.10725•Sep 9, 2026•0 citations
Isotope shifts among different isotopes can be effectively addressed using narrow-linewidth lasers, facilitating laser isotope separation and achieving significant enrichment at a single stage.The separation of potassium isotopes, employing optical pumping and magnetic deflection, has proven to be efficient.To further improve the enrichment of 40 K, we introduce 2D transverse cooling to minimize the divergence angle.Through this modification, we demonstrate enrichment of 40 K, elevating it from 0.012% to 12%-20%.This represents an enrichment increase by three orders of magnitude, surpassing our previous result by one order.Our method is particularly well-suited for isotope enrichment of elements with extremely low abundance.
Due to the similar physical and chemical properties, isotopes are usually hard to separate. On the other hand, the isotope shifts are very well separated in a high-resolution spectrum, making them possible to be addressed individually by lasers, thus separated. Here we report such an isotope separation experiment with Potassium atoms. The isotopes are independently optical pumped to the desired spin states, and then separated with a Stern-Gerlach scheme. A micro-capillary oven is used to collimate the atomic beam, and a Halbach-type magnet array is used to deflect the desired atoms. Finally, the 40K is enriched by two orders of magnitude. This magneto-optical combined method provides an effective way to separate isotopes and can be extended to other elements if the relevant optical pumping scheme is feasible.
We describe a novel method to enrich isotopes and isomers via magnetic deflection of optically polarized atomic beam. High electronic polarization with opposite signs for atoms of both isotopes respectively is achieved by selective optical pumping using lasers with different frequencies and polarizations and then the isotopes are enriched by deflecting the oppositely polarized isotopes along different directions by the inhomo-geneous magnetic field in the spin selective magnet. Separation selectivity and throughput are evaluated and the advantages, disadvantages and prospects of possible application of the present method are discussed in comparison with other existing methods. Experimental scheme with lithium or potassium is suggested.
Abstract We demonstrate the largest number of 40K atoms that has ever been cooled to deeply sub-Doppler temperatures in a single-chamber apparatus without using an enriched source of potassium. With gray molasses cooling on the D 1-line following a standard D 2-line magneto-optical trap, we obtain 3 × 10 5 atoms at 10(2) µK. We reach densities high enough to measure the temperature via absorption imaging using the time-of-flight method. We magnetically trap a mixture of m F = − 3 / 2 , − 5 / 2 and − 7 / 2 Zeeman states of the F = 7 / 2 hyperfine ground state confining 5 × 10 4 atoms with a lifetime of 0.6 s or ∼ 10 3 atoms with a lifetime of 2.8 s—depending on whether the temperature of the potassium dispensers was chosen to maximize the atom number or the lifetime. The background pressure-limited lifetime of 0.6 s is a reasonable starting point for proof-of-principle experiments with atoms and/or molecules in optical tweezers as well as for sympathetic cooling with another species if transport to a secondary chamber is implemented. Our results show that unenriched potassium can be used to optimize experimental setups containing 40K in the initial stages of their construction, which can effectively extend the lifetime of enriched sources. Moreover, the demonstration of sub-Doppler cooling and magnetic trapping of a relatively small number of potassium atoms might influence experiments with laser-cooled radioactive isotopes of potassium.
The authors have succeeded in demonstrating laser isotope enrichment via magnetic deflection of a polarized atomic beam. By using a single dye laser with the frequency tuned to the two accidentally close transitions of the natural lithium (2 2 S 1/2 (F=1/2) to 2 2 P 3/2 for 6 Li and 2 2 S 1/2 (F=2) to 2 2 P 1 2/(F=1) for 7 Li), 6 Li and 7 Li atoms in a beam were positively and negatively polarized respectively. The 6 Li enrichment was achieved via magnetic deflection of the polarized beam through a hexapole magnet which focuses the positively polarized 6 Li atoms and defocuses the negatively polarized 7 Li atoms. The dependence of 7 Li polarization on laser intensity was experimentally examined, and the result was in good agreement with that calculated by rate equations. The abundance ratio of 6 Li to 7 Li was enhanced from 1 : 12.5 to about 1 : 3.1.
40 K is one of the most important atomic species for ultra-cold atomic physics. Due to the extremely low concentration (0.012%) of 40 K in natural abundance of potassium, most experiments use 4–10% enriched potassium source, which have greatly suffered from the extremely low annual production and significant price hikes in recent years. Using naturally abundant potassium source, we capture 5.4×10 6 cold 40 K atoms with the help of a high performance of two-dimensional magneto-optical trap (2D + MOT), which is almost three orders of magnitude greater than previous results without the 2D + MOT. The number of the 40 K atoms is sufficient for most ultra-cold 40 K experiments, and our approach provides an ideal alternative for the field.
We realize narrow-linewidth magneto-optical traps of 46^{46}46Ti, 48^{48}48Ti and 50^{50}50Ti atoms based on a 1040 nm-wavelength transition, cooling atoms to a minimum temperature in one dimension of Tz=990(20)T_z=990(20)Tz​=990(20) nK and a three-dimensional temperature of T3D=1.28(7)T_\mathrm{3D}=1.28(7)T3D​=1.28(7) μμμK. Atoms are pre-cooled in a broad-line magneto-optical trap and then transferred with about 25% efficiency to the narrow-line trap. We operate the narrow-line trap in two stages over 85 ms. First, a single cooling beam, blue-detuned from the narrow-linewidth atomic resonance, optically pumps and traps the atoms on a two-dimensional surface where the Zeeman shift from the applied spherical quadrupole magnetic field brings the light nearly to resonance. Second, four additional beams, counter-propagating in the transverse directions, cool and compress the atoms in all dimensions. The high magnetic moment of the laser cooling state makes the dynamics of the narrow-line titanium trap similar to those of other magnetic atoms. We measure the lifetime of the excited state of the transition to be τ=8.2(9)τ=8.2(9)τ=8.2(9) μμμs, indicating a transition linewidth of γ/2π=20(2)γ/2π=20(2)γ/2π=20(2) kHz, and also measure isotope shifts on the narrow-line transition. We use Stern-Gerlach separation on the ultracold Ti gas to measure the mJm_JmJ​-distribution in the narrow-line magneto-optical trap, finding over 98% of the atoms in the stretched spin state.