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

Current Applied Physics

Experimental apparatus for production and transport of a 6Li quantum gas

Seongwook Hong, Sungjae Won, Giacomo do Hvaring, Andrea Vecchione, Woo Jin Kwon

Published Jun 9, 2026• 0 citations
Publisher

Abstract

We report our experimental apparatus for producing 6 Li quantum gases with good optical access. Atoms are first captured in a D 2 magneto-optical trap (MOT) and subsequently cooled via a compressed MOT and D 1 gray molasses, reaching sub-Doppler temperatures as low as 70 μ K . The cold atoms are then loaded into a single-beam optical dipole trap and transported into a compact octagonal glass cell, where forced evaporative cooling is performed. We achieve quantum degeneracy, observe the formation of a molecular Bose–Einstein condensate containing 1 × 10 5 atom pairs, and demonstrate controlled tomographic imaging, thereby establishing a versatile platform for future studies of three-dimensional (3D) superfluid dynamics.

DOI
10.1016/j.cap.2026.06.001

Related papers

All-optical production of6Li quantum gases

A. Burchianti, Jorge Amin Seman, Giacomo Valtolina +4 more

We report efficient production of quantum gases of 6 Li using a sub-Doppler cooling scheme based on the D 1 transition. After loading in a standard magneto-optical trap, an atomic sample of 10 9 atoms is cooled at a temperature of 40 μ K by a bichromatic D 1 gray-molasses. More than 2 × 10 7 atoms are then transferred into a high-intensity optical dipole trap, where a two-spin state mixture is evaporatively cooled down to quantum degeneracy. We observe that D 1 cooling remains effective in the deep trapping potential, allowing an effective increase of the atomic phase-space density before starting the evaporation. In a total experimental cycle of 11 s, we produce weakly-interacting degenerate Fermi gases of 7 × 10 5 atoms at T/T F < 0.1 and molecular Bose-Einstein condensates of up 5 × 10 5 molecules. We further describe a simple and compact optical system both for high-resolution imaging and for imprinting a thin optical barrier on the atomic cloud; this represents a first step towards the study of quantum tunneling in strongly interacting superfluid Fermi gases.

Journal of Physics Conference Series•Mar 18, 2015•5 citations

Cooling 6Li to Quantum Degeneracy by 166Er in a Novel Ultracold Fermi-Bose Gas Mixture

Florian Johannes Kiesel

Simulating highly correlated quantum systems with classical computers exceed their capa- bilities as the system size increases. In analog quantum simulators, the system of interest is mimicked by another quantum system in a highly controllable and accessible environ- ment. Even though quantum simulations with ultracold atoms have been demonstrated successfully, ultra-low temperature regimes are experimentally challenging to achieve and still remain to be explored. New approaches to realizing ever lower temperatures, especially in Fermi systems, have been and continue to be a constant pursuit in Atomic, Molecular, and Optical Physics (AMO). Within this thesis, a new quantum gas experiment of fermionic 6Li and bosonic 166Er is presented and first results on sympathetic cooling of Li to quantum degeneracy by Er are demonstrated. The experimental apparatus is described in detail with a focus on the Li subsystem of the dual-species experiment. Standard and further developed laser cooling techniques used to produce a Magneto-Optical Trap (MOT) of Li are characterized, along with their associated vacuum system stages. In this context, a combined Optical Pumping / Transversal Cooling (OP/TC) technique of the atomic beam on the D1-line is presented, and an enhancement of the MOT loading rate by one order of magnitude is demonstrated. The architecture and building blocks of the laser system for providing resonant light at 671 nm for laser cooling of Li are detailed, and laser locking techniques for frequency stabilization and light amplification by injection locking of high-power laser diodes are presented. Special focus is placed on the introduction and characterization of a new laser- diode-independent injection locking technique, keeping spectrally pure amplified light by a periodic slave current optimization routine executed by a microcontroller. The system has been submitted for patent approval. In further steps of optical cooling of Li, a non-standard free-space Gray Molasses (GM) technique based on intensity ramps, providing temperatures as low as 13 µK, is presented. The non-standard technique is characterized and compared to the standard pulse GM approach, which typically achieves 50 µK only. Cooling steps for preparing an ultracold Li cloud in the glass cell start from an Optical Dipole Trap (ODT) loaded by a compressed Magneto-Optical Trap (cMOT) and consecutive evaporation into a 1D transport lattice of counter propagating 1064 nm laser beams. By detuning one of the lattice beams, optical transport over 1 m to the glass cell with an efficiency of 74% is demonstrated. In a combined ErLi sequence, the two species are transported to the glass cell together and loaded to 1064 nm ODTs. Sympathetic cooling of Li by forced evaporation of Er to T/TF = 0.77 ± 0.10 next to the production of an Er BEC are presented. To conclude, this work introduces a new promising dual-species quantum gas experiment and its ability for providing sympathetic cooling of Li by Er to quantum degeneracy is demon- strated. These findings are an encouraging foundation for achieving higher degeneracies by refined experimental control in pursuit of penetrating unexplored temperature regimes in quantum simulators.

•Feb 20, 2026•0 citations

Efficient all-optical production of large [superscript 6]Li quantum gases using D[subscript 1] gray-molasses cooling

A. Burchianti, Giacomo Valtolina, Jorge Amin Seman +5 more

We use a gray molasses operating on the D[subscript 1] atomic transition to produce degenerate quantum gases of [superscript 6]Li with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of 10[superscript 9] atoms from 500 to 40 μK in 2 ms. We observe that D[subscript 1] cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5 × 10[superscript 5] molecules and weakly interacting degenerate Fermi gases of 7×10[superscript 5] atoms at T/T[subscript F] < 0.1 with a typical experimental duty cycle of 11 s.

Physical Review Letters•Oct 1, 2014•0 citations

Molecular Bose–Einstein condensation in a versatile low power crossed dipole trap

Jean-Noël Fuchs, G J Duffy, G. Veeravalli +5 more

We produce Bose–Einstein condensates of 6 Li 2 molecules in a low power (22 W) crossed optical dipole trap. Fermionic 6 Li atoms are collected in a magneto-optical trap from a Zeeman slowed atomic beam and then loaded into the optical dipole trap where they are evaporatively cooled to quantum degeneracy. Our simplified system offers a high degree of flexibility in trapping geometry for studying ultracold Fermi and Bose gases.

arXiv:0709.2212•Journal of Physics B Atomic Molecular and Optical Physics•Oct 9, 2007•25 citations

Production of Degenerate Fermi Gases of 6Li Atoms in an Optical Dipole Trap

Xiangchuan Yan, Da-Li Sun, Lu Wang +3 more

We report the experimental production of degenerate Fermi gases of 6Li atoms in an optical dipole trap. The gray-molasses technique is carried out to decrease the atomic temperature to 57 μK, which facilitates the efficient loading of cold atoms into the optical dipole trap. The Fermi degeneracy is achieved by evaporative cooling of a two-spin mixture of 6Li atoms on the Feshbach resonance. The degenerate atom number per spin is 3.5 × 104, and the reduced temperature T/T F is as low as 0.1, where T F is the Fermi temperature of the non-interacting Fermi gas. We also observe the anisotropic expansion of the atom cloud in the strongly interacting regime.

Chinese Physics Letters•Jun 1, 2021•8 citations

Efficient all-optical production of large Li6 quantum gases using D1 gray-molasses cooling

A. Burchianti, Giacomo Valtolina, Jorge Amin Seman +5 more

We use a gray molasses operating on the ${D}_{1}$ atomic transition to produce degenerate quantum gases of $^{6}\mathrm{Li}$ with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of $10{}^{9}$ atoms from 500 to 40 $\ensuremath{\mu}\mathrm{K}$ in 2 ms. We observe that ${D}_{1}$ cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5 $\ifmmode\times\else\texttimes\fi{}$ $10{}^{5}$ molecules and weakly interacting degenerate Fermi gases of $7\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms at $T/{T}_{F}<0.1$ with a typical experimental duty cycle of 11 s.

arXiv:1406.4788•Physical Review A•Oct 8, 2014•101 citations
We report our experimental apparatus for producing 6 Li quantum gases with good optical access. Atoms are first captured in a D 2 magneto-optical trap (MOT) and subsequently cooled via a compressed MOT and D 1 gray molasses, reaching sub-Doppler temperatures as low as 70 μ K . The cold atoms are then loaded into a single-beam optical dipole trap and transported into a compact octagonal glass cell, where forced evaporative cooling is performed. We achieve quantum degeneracy, observe the formation of a molecular Bose–Einstein condensate containing 1 × 10 5 atom pairs, and demonstrate controlled tomographic imaging, thereby establishing a versatile platform for future studies of three-dimensional (3D) superfluid dynamics.
We report efficient production of quantum gases of 6 Li using a sub-Doppler cooling scheme based on the D 1 transition. After loading in a standard magneto-optical trap, an atomic sample of 10 9 atoms is cooled at a temperature of 40 μ K by a bichromatic D 1 gray-molasses. More than 2 × 10 7 atoms are then transferred into a high-intensity optical dipole trap, where a two-spin state mixture is evaporatively cooled down to quantum degeneracy. We observe that D 1 cooling remains effective in the deep trapping potential, allowing an effective increase of the atomic phase-space density before starting the evaporation. In a total experimental cycle of 11 s, we produce weakly-interacting degenerate Fermi gases of 7 × 10 5 atoms at T/T F < 0.1 and molecular Bose-Einstein condensates of up 5 × 10 5 molecules. We further describe a simple and compact optical system both for high-resolution imaging and for imprinting a thin optical barrier on the atomic cloud; this represents a first step towards the study of quantum tunneling in strongly interacting superfluid Fermi gases.
Simulating highly correlated quantum systems with classical computers exceed their capa- bilities as the system size increases. In analog quantum simulators, the system of interest is mimicked by another quantum system in a highly controllable and accessible environ- ment. Even though quantum simulations with ultracold atoms have been demonstrated successfully, ultra-low temperature regimes are experimentally challenging to achieve and still remain to be explored. New approaches to realizing ever lower temperatures, especially in Fermi systems, have been and continue to be a constant pursuit in Atomic, Molecular, and Optical Physics (AMO). Within this thesis, a new quantum gas experiment of fermionic 6Li and bosonic 166Er is presented and first results on sympathetic cooling of Li to quantum degeneracy by Er are demonstrated. The experimental apparatus is described in detail with a focus on the Li subsystem of the dual-species experiment. Standard and further developed laser cooling techniques used to produce a Magneto-Optical Trap (MOT) of Li are characterized, along with their associated vacuum system stages. In this context, a combined Optical Pumping / Transversal Cooling (OP/TC) technique of the atomic beam on the D1-line is presented, and an enhancement of the MOT loading rate by one order of magnitude is demonstrated. The architecture and building blocks of the laser system for providing resonant light at 671 nm for laser cooling of Li are detailed, and laser locking techniques for frequency stabilization and light amplification by injection locking of high-power laser diodes are presented. Special focus is placed on the introduction and characterization of a new laser- diode-independent injection locking technique, keeping spectrally pure amplified light by a periodic slave current optimization routine executed by a microcontroller. The system has been submitted for patent approval. In further steps of optical cooling of Li, a non-standard free-space Gray Molasses (GM) technique based on intensity ramps, providing temperatures as low as 13 µK, is presented. The non-standard technique is characterized and compared to the standard pulse GM approach, which typically achieves 50 µK only. Cooling steps for preparing an ultracold Li cloud in the glass cell start from an Optical Dipole Trap (ODT) loaded by a compressed Magneto-Optical Trap (cMOT) and consecutive evaporation into a 1D transport lattice of counter propagating 1064 nm laser beams. By detuning one of the lattice beams, optical transport over 1 m to the glass cell with an efficiency of 74% is demonstrated. In a combined ErLi sequence, the two species are transported to the glass cell together and loaded to 1064 nm ODTs. Sympathetic cooling of Li by forced evaporation of Er to T/TF = 0.77 ± 0.10 next to the production of an Er BEC are presented. To conclude, this work introduces a new promising dual-species quantum gas experiment and its ability for providing sympathetic cooling of Li by Er to quantum degeneracy is demon- strated. These findings are an encouraging foundation for achieving higher degeneracies by refined experimental control in pursuit of penetrating unexplored temperature regimes in quantum simulators.
We use a gray molasses operating on the D[subscript 1] atomic transition to produce degenerate quantum gases of [superscript 6]Li with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of 10[superscript 9] atoms from 500 to 40 μK in 2 ms. We observe that D[subscript 1] cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5 × 10[superscript 5] molecules and weakly interacting degenerate Fermi gases of 7×10[superscript 5] atoms at T/T[subscript F] < 0.1 with a typical experimental duty cycle of 11 s.
We report the experimental production of degenerate Fermi gases of 6Li atoms in an optical dipole trap. The gray-molasses technique is carried out to decrease the atomic temperature to 57 μK, which facilitates the efficient loading of cold atoms into the optical dipole trap. The Fermi degeneracy is achieved by evaporative cooling of a two-spin mixture of 6Li atoms on the Feshbach resonance. The degenerate atom number per spin is 3.5 × 104, and the reduced temperature T/T F is as low as 0.1, where T F is the Fermi temperature of the non-interacting Fermi gas. We also observe the anisotropic expansion of the atom cloud in the strongly interacting regime.
We use a gray molasses operating on the D1{D}_{1}D1​ atomic transition to produce degenerate quantum gases of 6Li^{6}\mathrm{Li}6Li with a large number of atoms. This sub-Doppler cooling phase allows us to lower the initial temperature of 10910{}^{9}109 atoms from 500 to 40 $\ensuremath{\mu}\mathrm{K}$ in 2 ms. We observe that D1{D}_{1}D1​ cooling remains effective into a high-intensity infrared dipole trap where two-state mixtures are evaporated to reach the degenerate regime. We produce molecular Bose-Einstein condensates of up to 5 $\ifmmode\times\else\texttimes\fi{}$ 10510{}^{5}105 molecules and weakly interacting degenerate Fermi gases of $7\ifmmode\times\else\texttimes\fi{}{10}^{5}$ atoms at T/TF<0.1T/{T}_{F}<0.1T/TF​<0.1 with a typical experimental duty cycle of 11 s.