FIG. 6. Bose-Einstein condensation of 174Yb by evaporative cooling. The top panels show absorption images taken after a 25-ms 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 TYb = 500 nK (left), across the BEC transition to TYb = 300 nK (middle). Finally, at the end of evaporation a pure condensate (right) is produced containing 3 × 105 atoms.
...read more