Optical Confinement of a Bose-Einstein Condensate

Bose-Einstein condensates of sodium atoms have been confined in an optical dipole trap using a single focused infrared laser beam. This eliminates the restrictions of magnetic traps for further studies of atom lasers and Bose-Einstein condensates. More than $5\times {10}^6$ condensed atoms were transferred into the optical trap. Densities of up to $3\times {10}^{15}{\mathrm{cm}}^{-3\mathrm{}}$ of Bose condensed atoms were obtained, allowing for a measurement of the three-body loss rate constant for sodium condensates as $K_3=1.1\mathrm{}\left(3\right)\times {10}^{-30\mathrm{}}{\mathrm{cm}}^6{\mathrm{s}}^{-1\mathrm{}}$. At lower densities, the observed $1/e$ lifetime was longer than 10 s. Simultaneous confinement of Bose-Einstein condensates in several hyperfine states was demonstrated.