Evaporative Cooling in a Crossed Dipole Trap

Laser cooled sodium atoms are trapped in an optical dipole force trap formed by the intersection of two 1. 06 laser beams. Densities as high as 410^12 atoms/cm^3 at a temperature of 140 have been obtained in a 900 deep trap. By reducing the trap depth over a 2 s interval, we have evaporatively cooled the atoms to a final temperature of 4 at a density of 610^11 atoms/cm^3. This corresponds to a factor of 28 increase in atomic phase-space density.