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High-flux cold Li6 and Rb87 atoms from compact two-dimensional magneto-optical traps

Yun-Xuan Lu1,2,*, An-Wei Zhu1,2,*, Christine E. Frank1,2, Xin-Yi Huang1,2, and Xin-Yu Luo1,3,†

  • *These authors contributed equally to this work.
  • †Contact author: xinyu.luo@mpq.mpg.de
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Phys. Rev. A 113, 053309 – Published 11 May, 2026

DOI: https://doi.org/10.1103/g448-4p5n

Abstract

Integrating two chemically distinct atomic species into a miniaturized, high-flux cold-atom source is a key challenge for modern experiments with ultracold atomic mixtures and polar molecules. Here, we report a compact setup with in-series two-dimensional magneto-optical traps (2D MOTs) that provides high-flux cold lithium and rubidium atoms. Thanks to the efficient short-distance Zeeman slowing, the maximum 3D MOT loading rate of lithium atoms reaches a record value of 6.6×109 atoms/s at a moderate lithium-oven temperature of 372 degrees Celsius, which is 44 times higher than that without the Zeeman slowing light. The flux of rubidium is also as high as 2.3×109 atoms/s with the rubidium oven held at room temperature. Meanwhile, the entire vacuum-chamber system, including an ultra-high-vacuum science cell, is within a small volume of 65×55×70cm3. Our work represents a substantial improvement over traditional bulky and complex dual-species cold-atom setups. It provides a good starting point for the fast production of a double-degenerate lithium-rubidium atomic mixture and large samples of ultracold lithium-rubidium ground-state molecules.

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References (55)

  1. L. D. Carr, D. DeMille, R. V. Krems, and J. Ye, Cold and ultracold molecules: Science, technology and applications, New J. Phys. 11, 055049 (2009).
  2. S. Moses, J. Covey, M. Miecnikowski, D. Jin, and J. Ye, New frontiers for quantum gases of polar molecules, Nat. Phys. 13, 13 (2017).
  3. Y. Yin, X. Bai, X. Li, J. Yu, G. Wang, Y. Han, and X.-Y. Luo, Genetics-based deperturbation analysis for the spin-orbit-coupled AΣ+1 and bΠ0+3 states of LiRb, Phys. Rev. A 110, 042812 (2024).
  4. F. Deng, X.-Y. Chen, X.-Y. Luo, W. Zhang, S. Yi, and T. Shi, Effective potential and superfluidity of microwave-shielded polar molecules, Phys. Rev. Lett. 130, 183001 (2023).
  5. C. Silber, S. Günther, C. Marzok, B. Deh, P. W. Courteille, and C. Zimmermann, Quantum-degenerate mixture of fermionic lithium and bosonic rubidium gases, Phys. Rev. Lett. 95, 170408 (2005).
  6. M. Taglieber, A.-C. Voigt, T. Aoki, T. W. Hänsch, and K. Dieckmann, Quantum degenerate two-species Fermi-Fermi mixture coexisting with a Bose-Einstein condensate, Phys. Rev. Lett. 100, 010401 (2008).
  7. B. Deh, C. Marzok, C. Zimmermann, and P. W. Courteille, Feshbach resonances in mixtures of ultracold Li6 and Rb87 gases, Phys. Rev. A 77, 010701(R) (2008).
  8. B. Deh, W. Gunton, B. G. Klappauf, Z. Li, M. Semczuk, J. Van Dongen, and K. W. Madison, Giant Feshbach resonances in Li6−Rb85 mixtures, Phys. Rev. A 82, 020701(R) (2010).
  9. W. D. Phillips and H. Metcalf, Laser deceleration of an atomic beam, Phys. Rev. Lett. 48, 596 (1982).
  10. M. A. Joffe, W. Ketterle, A. Martin, and D. E. Pritchard, Transverse cooling and deflection of an atomic beam inside a Zeeman slower, J. Opt. Soc. Am. B 10, 2257 (1993).
  11. M.-O. Mewes, G. Ferrari, F. Schreck, A. Sinatra, and C. Salomon, Simultaneous magneto-optical trapping of two lithium isotopes, Phys. Rev. A 61, 011403(R) (1999).
  12. Z. Hadzibabic, C. A. Stan, K. Dieckmann, S. Gupta, M. W. Zwierlein, A. Görlitz, and W. Ketterle, Two-species mixture of quantum degenerate Bose and Fermi gases, Phys. Rev. Lett. 88, 160401 (2002).
  13. M. Taglieber, A.-C. Voigt, F. Henkel, S. Fray, T. W. Hänsch, and K. Dieckmann, Simultaneous magneto-optical trapping of three atomic species, Phys. Rev. A 73, 011402(R) (2006).
  14. G. E. Marti, R. Olf, E. Vogt, A. Öttl, and D. M. Stamper-Kurn, Two-element Zeeman slower for rubidium and lithium, Phys. Rev. A 81, 043424 (2010).
  15. A. Ridinger, S. Chaudhuri, T. Salez, U. Eismann, D. R. Fernandes, K. Magalhães, D. Wilkowski, C. Salomon, and F. Chevy, Large atom number dual-species magneto-optical trap for fermionic Li6 and K40 atoms, Eur. Phys. J. D 65, 223 (2011).
  16. J. W. Park, C.-H. Wu, I. Santiago, T. G. Tiecke, S. Will, P. Ahmadi, and M. W. Zwierlein, Quantum degenerate Bose-Fermi mixture of chemically different atomic species with widely tunable interactions, Phys. Rev. A 85, 051602(R) (2012).
  17. S. A. Hopkins, K. Butler, A. Guttridge, S. Kemp, R. Freytag, E. A. Hinds, M. R. Tarbutt, and S. L. Cornish, A versatile dual-species Zeeman slower for caesium and ytterbium, Rev. Sci. Instrum. 87, 043109 (2016).
  18. Y.-P. Wu, X.-C. Yao, H.-Z. Chen, X.-P. Liu, X.-Q. Wang, Y.-A. Chen, and J.-W. Pan, A quantum degenerate Bose–Fermi mixture of K41 and Li6, J. Phys. B: At. Mol. Opt. Phys. 50, 094001 (2017).
  19. P. Ilzhöfer, G. Durastante, A. Patscheider, A. Trautmann, M. J. Mark, and F. Ferlaino, Two-species five-beam magneto-optical trap for erbium and dysprosium, Phys. Rev. A 97, 023633 (2018).
  20. X. Ma, Z. Ye, L. Xie, Z. Guo, L. You, and M. K. Tey, A dual-species magneto-optical trap for lithium and strontium atoms, arXiv:1904.05230.
  21. R. G. Hulet, J. H. V. Nguyen, and R. Senaratne, Methods for preparing quantum gases of lithium, Rev. Sci. Instrum. 91, 011101 (2020).
  22. C. Warner, A. Z. Lam, N. Bigagli, H. C. Liu, I. Stevenson, and S. Will, Overlapping Bose-Einstein condensates of Na23 and Cs133, Phys. Rev. A 104, 033302 (2021).
  23. M. Vayninger, A. Xiang, N. D. Bhanushali, X. Chen, M. Verma, S. Yang, R. T. Kapur, D. DeMille, and Z. Z. Yan, A magneto-optical trap of silver and potassium atoms Phys. Rev. A 112, 063306 (2025).
  24. K. Dieckmann, R. J. C. Spreeuw, M. Weidemüller, and J. T. M. Walraven, Two-dimensional magneto-optical trap as a source of slow atoms, Phys. Rev. A 58, 3891 (1998).
  25. A. Z. Lam, C. Warner, N. Bigagli, S. Roschinski, W. Yuan, I. Stevenson, and S. Will, Compact two-dimensional magneto-optical trap for ultracold atom setups, arXiv:2012.06688.
  26. Y.-D. Chen, W.-X. Li, M.-E. Chou, C.-H. Kuo, C.-S. Li, and S. Tung, Lithium-cesium slow beam from a two-dimensional magneto-optical trap, Phys. Rev. A 103, 023102 (2021).
  27. C. Pür, M. Hetzel, M. Quensen, A. Hüper, J. Geng, J. Kruse, W. Ertmer, and C. Klempt, Rapid generation and number-resolved detection of spinor rubidium Bose-Einstein condensates, Phys. Rev. A 107, 033303 (2023).
  28. S. Sutradhar, A. Misra, G. Pal, S. Majumder, S. Roy, and S. Chaudhuri, Fast loaded dual species magneto optical trap of cold sodium and potassium atoms with light-assisted inter-species interaction, AIP Adv. 13, 065317 (2023).
  29. A. J. Matthies, J. M. Mortlock, L. A. McArd, A. P. Raghuram, A. D. Innes, P. D. Gregory, S. L. Bromley, and S. L. Cornish, Long-distance optical-conveyor-belt transport of ultracold Cs133 and Rb87 atoms, Phys. Rev. A 109, 023321 (2024).
  30. T. G. Tiecke, S. D. Gensemer, A. Ludewig, and J. T. M. Walraven, High-flux two-dimensional magneto-optical-trap source for cold lithium atoms, Phys. Rev. A 80, 013409 (2009).
  31. T. Hammel, M. Kaiser, D. Dux, P. M. Preiss, M. Weidemüller, and S. Jochim, Modular quantum gas platform, Phys. Rev. A 111, 033314 (2025).
  32. N. Jain, J. Zhang, M. Culemann, and P. M. Preiss, Programmable assembly of ground state fermionic tweezer arrays, arXiv:2512.09849.
  33. G. Lamporesi, S. Donadello, S. Serafini, and G. Ferrari, Compact high-flux source of cold sodium atoms, Rev. Sci. Instrum. 84, 063102 (2013).
  34. Z.-L. Li, Z.-L. Shi, and P.-J. Wang, Design and research of two-dimensional magneto-optical trap of sodium atom using permanent magnets, Acta Phys. Sin. 69, 126701 (2020).
  35. Z. Li, Z. Gu, Z. Shi, P. Wang, and J. Zhang, Quantum degenerate Bose-Fermi atomic gas mixture of Na23 and K40, Chin. Phys. B 32, 023701 (2023).
  36. I. Nosske, L. Couturier, F. Hu, C. Tan, C. Qiao, J. Blume, Y. H. Jiang, P. Chen, and M. Weidemüller, Two-dimensional magneto-optical trap as a source for cold strontium atoms, Phys. Rev. A 96, 053415 (2017).
  37. E. Wodey, R. J. Rengelink, C. Meiners, E. M. Rasel, and D. Schlippert, A robust, high-flux source of laser-cooled ytterbium atoms, J. Phys. B 54, 035301 (2021).
  38. S. Biswas, S. Eppelt, C. Buchberger, X.-Y. Chen, A. Schindewolf, M. Hani, E. Biebl, I. Bloch, and X.-Y. Luo, Generation of strong ultralow-phase-noise microwave fields with tunable ellipticity for ultracold polar molecules, Rev. Sci. Instrum. 97, 044706 (2026).
  39. M. E. Gehm, Preparation of an optically-trapped degenerate Fermi gas of Li6: Finding the route to degeneracy, Ph.D. thesis, Duke University, 2003.
  40. The Li oven temperature is monitored by two thermocouples attached to the top and bottom of the oven body within thermal insulation. Due to the temperature gradient within the oven, the measured temperatures are lower than the actual temperature of the Li sample inside the stainless steel oven. Moreover, any loose connection or imperfect thermal contact between the thermocouple and the oven wall can lead to inaccurate temperature readings. To account for thermal gradients and any possible deviations, the readings were calibrated in situ using the observed temperature plateau during the solid-to-liquid phase transition of the Li6 sample. A two-point calibration was then applied using room temperature (20.9∘C) and the literature melting point of Li6 (180.5∘C). All lithium oven temperatures reported in this work were calibrated following the above procedure.
  41. C. Gross (private communication).
  42. D. A. Steck, Rubidium 87 D line data, http://steck.us/alkalidata.
  43. D. A. Steck, Rubidium 85 D line data, http://steck.us/alkalidata.
  44. D. Das and V. Natarajan, Absolute frequency measurement of the lithium D lines: Precise determination of isotope shifts and fine-structure intervals, Phys. Rev. A 75, 052508 (2007).
  45. C.-H. Wei and S.-H. Yan, Simple and robust method for rapid cooling of Rb87 to quantum degeneracy, Chin. Phys. B 29, 064208 (2020).
  46. J. Ye, S. Swartz, P. Jungner, and J. L. Hall, Hyperfine structure and absolute frequency of the Rb875P3/2 state, Opt. Lett. 21, 1280 (1996).
  47. A. M. Steane, M. Chowdhury, and C. J. Foot, Radiation force in the magneto-optical trap, J. Opt. Soc. Am. B 9, 2142 (1992).
  48. C. Monroe, W. Swann, H. Robinson, and C. Wieman, Very cold trapped atoms in a vapor cell, Phys. Rev. Lett. 65, 1571 (1990).
  49. T. P. Dinneen, K. R. Vogel, E. Arimondo, J. L. Hall, and A. Gallagher, Cold collisions of Sr* - Sr in a magneto-optical trap, Phys. Rev. A 59, 1216 (1999).
  50. F. Serwane, The setup of a magneto optical trap for the preparation of a mesoscopic degenerate Fermi gas, Master's thesis, University of Heidelberg, Max-Planck-Institute for Nuclear Physics, 2007.
  51. C. Chen, K. Liu, D. Deng, S. Ma, P. Zhu, Z. He, J. F. Che, X. Wu, and P. Chen, A compact dual-beam Zeeman slower for high-flux cold atoms, Phys. Rev. Appl. 24, 054071 (2025).
  52. T. Hammel, Design and construction of a new experiment for programmable quantum simulation using ultracold Li6 fermions, Master's thesis, Physikalisches Institut Heidelberg, 2021.
  53. S. Jöllenbeck, J. Mahnke, R. Randoll, W. Ertmer, J. Arlt, and C. Klempt, Hexapole-compensated magneto-optical trap on a mesoscopic atom chip, Phys. Rev. A 83, 043406 (2011).
  54. B. Höltkemeier, 2D MOT as a source of a cold atom target, Diploma thesis, University of Heidelberg, 2011.
  55. M. Parry, Construction, and performance towards a versatile Rb87 & K41 BEC apparatus, Master's thesis, The University of Queensland, 2015.

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Phys. Rev. A 113, 053309– Published 11 May, 2026
  • Received 5 January 2026
  • Accepted 16 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by Max Planck Society.

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