All optical cooling of ³⁹K to Bose Einstein condensation

2014/07/20 by Guillaume Salomon, Lauriane Fouché, Steven Lepoutre +2
Physics and Astronomy · #cond-mat.quant-gas #physics.atom-ph

paper · pdf · doi:10.1103/physreva.90.033405

arxiv created 2014/07/20 · arxiv updated 2015/06/22

Abstract

We report the all-optical production of Bose Einstein condensates (BEC) of ³⁹K atoms. We directly load 3 × 10⁷ atoms in a large volume optical dipole trap from gray molasses on the D1 transition. We then apply a small magnetic quadrupole field to polarize the sample before transferring the atoms in a tightly confining optical trap. Evaporative cooling is finally performed close to a Feshbach resonance to enhance the scattering length. Our setup allows to cross the BEC threshold with 3 × 10⁵ atoms every 7s. As an illustration of the interest of the tunability of the interactions we study the expansion of Bose-Einstein condensates in the 1D to 3D crossover.

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