FIG. 7. Bose-Einstein condensation of Cs by evaporative cooling. The top panels show absorption images taken after 50 ms of levitated time of flight. The bottom panels show the corresponding horizontal crosscuts through the images. The laser power of the optical dipole trap is gradually reduced, cooling the atoms from a thermal cloud at TCs = 70 nK (left), across the BEC transition to TCs = 50 nK (middle). Finally, at the end of evaporation a pure condensate (right) is produced containing 5 × 104 atoms.
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