We report efficient production of quantum gases of Li-6 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 mu K by a bichromatic D-1 gray-molasses. More than 2x10(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 7x10(5) atoms at T/T-F < 0.1 and molecular Bose-Einstein condensates of up 5x10(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.
All-optical production of Li-6 quantum gases
Burchianti A;Valtolina G;Zaccanti M;Roati G
2015
Abstract
We report efficient production of quantum gases of Li-6 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 mu K by a bichromatic D-1 gray-molasses. More than 2x10(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 7x10(5) atoms at T/T-F < 0.1 and molecular Bose-Einstein condensates of up 5x10(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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.