Optical cooling and trapping of highly magnetic atoms: The benefits of a spontaneous spin polarization

Abstract

From the study of long-range-interacting systems to the simulation of gauge fields, open-shell Lanthanide atoms with their large magnetic moment and narrow optical transitions open novel directions in the field of ultracold quantum gases. As for other atomic species, the magneto-optical trap (MOT) is the working horse of experiments but its operation is challenging, due to the large electronic spin of the atoms. Here we present an experimental study of narrow-line Dysprosium MOTs. We show that the combination of radiation pressure and gravitational forces leads to a spontaneous polarization of the electronic spin. The spin composition is measured using a Stern-Gerlach separation of spin levels, revealing that the gas becomes almost fully spin-polarized for large laser frequency detunings. In this regime, we reach the optimal operation of the MOT, with samples of typically $3\times 10^8$ atoms at a temperature of 15\,$\mu$K. The spin polarization reduces the complexity of the radiative cooling description, which allows for a simple model accounting for our measurements. We also measure the rate of density-dependent atom losses, finding good agreement with a model based on light-induced Van der Waals forces. A minimal two-body loss rate $\beta \sim 2\times 10^{-11}$cm${}^3$/s is reached in the spin-polarized regime. Our results constitute a benchmark for the experimental study of ultracold gases of magnetic Lanthanide atoms.

21 pages, 9 figures

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Cited by in corpus (27)

• Dipolar physics: A review of experiments with magnetic quantum gases
• Dipolar Quantum Mixtures of Erbium and Dysprosium Atoms
• Quantum-enhanced sensing using non-classical spin states of a highly magnetic atom
• Production of a degenerate Fermi-Fermi mixture of dysprosium and potassium atoms
• A two-species five-beam magneto-optical trap for highly magnetic Er and Dy atoms
• Accurate Determination of the Dynamical Polarizability of Dysprosium
• Dysprosium dipolar Bose-Einstein condensate with broad Feshbach resonances
• Enhancing the capture velocity of a Dy magneto-optical trap with two-stage slowing
• Bose-Einstein Condensation of Europium
• Anisotropic optical trapping as a manifestation of the complex electronic structure of ultracold lanthanide atoms: the example of holmium
• Trapping and imaging single dysprosium atoms in optical tweezer arrays
• Two-temperature momentum distribution in a Thulium magneto-optical trap
• Narrow-line magneto-optical trap for europium
• Polarized cold cloud of thulium atom
• A two-dimensional magneto-optical trap of dysprosium atoms as a compact source for efficient loading of a narrow-line three-dimensional magneto-optical trap
• Ultracold rare-earth magnetic atoms with an electric dipole moment
• A steady-state magneto-optical trap of fermionic strontium on a narrow-line transition
• Bose-Einstein condensation of erbium atoms in a quasielectrostatic optical dipole trap
• A new setup for experiments with ultracold Dysprosium atoms
• Measurement of the dynamic polarizability of Dy atoms near the 626-nm intercombination line
• Comprehensive characterization of an apparatus for cold electromagnetic dysprosium dipoles
• New opportunites for interactions and control with ultracold lanthanides
• Purely long-range polar molecules composed of identical lanthanide atoms
• Creation of a degenerate Bose-Bose mixture of erbium and lithium atoms
• Laser Cooling at Resonance
• Improving the spectroscopic knowledge of neutral Neodymium
• Low-field Feshbach resonances and three-body losses in a fermionic quantum gas of ${}^{161}$Dy