All optical cooling of $^{39}$K to Bose Einstein condensation

G. Salomon (1) , L. Fouché (1) , S. Lepoutre (1) , Alain Aspect (1) , Thomas Bourdel (1)

1 Laboratoire Charles Fabry / Optique atomique

We report the all-optical production of Bose Einstein condensates (BEC) of $^{39}$K atoms. We directly load $3 \times 10^{7}$ 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 $3 \times 10^5$ 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.

Domaines: Physique Atomique [physics.atom-ph]

G. Salomon, L. Fouché, S. Lepoutre, Alain Aspect, Thomas Bourdel. All optical cooling of $^{39}$K to Bose Einstein condensation. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2014, 90 (3), pp.033405. ⟨10.1103/PhysRevA.90.033405⟩. ⟨hal-01026128⟩