Experiments with optically trapped sodium atoms

A series of experiments have been performed with optically trapped sodium atoms. The goal of these experiments was to find innovative roles for far-detuned optical dipole traps in the areas of atom interferometry and laser cooling. A particular focus related to the latter goal was the attainment of Bose-Einstein Condensation (BEC) by performing laser cooling on optically trapped atoms. Up to 106 optically trapped atoms have been cooled to phase space densities as high as ∼1/70 in 150 milliseconds. These results represented one of the closest approaches to BEC by primarily optical means; moreover, the cooling times are one to two orders of magnitude less than that needed by rf evaporation. Additional experiments demonstrating the benefits of an optically based approach are discussed, namely, demonstrations of long coherence times and evaporative cooling.