All-optical production and transport of a large Li-6 quantum gas in a crossed optical dipole trap

Abstract

We report on an efficient production scheme for a large quantum degenerate sample of fermionic lithium. The approach is based on our previous work on narrow-line 2S1/2→3P3/2 laser cooling resulting in a high phase-space density of up to 3×10-4. This allows utilizing a large-volume crossed optical dipole trap with a total power of 45W, leading to high loading efficiency and 8×106 trapped atoms. The same optical trapping configuration is used for rapid adiabatic transport over a distance of 25cm in 0.9s, and subsequent evaporative cooling. With optimized evaporation we achieve a degenerate Fermi gas with 1.7×106 atoms at a temperature of 60nK, corresponding to T/TF=0.162. Furthermore, the performance is demonstrated by evaporation near a broad Feshbach resonance creating a molecular Bose-Einstein condensate of 3×105 lithium dimers.