Time-averaged optical dipole traps for Bose-Einstein condensates

摘要

We report on our progress towards realization of a toroidal trap for Bose-Einstein condensates (BECs) of 87Rb using a time-averaged optical dipole potential. To achieve BEC we utilize a 20 W laser operating at 1064 nm to form an optical dipole trap in which we evaporatively cool the gas. Loading of the dipole trap is achieved by overlapping the dipole beams with a standard magnetic optical trap. Evaporative cooling is first performed in a single beam trap, followed by compression and additional confinement with a second orthogonal beam. This prevents stagnation of the evaporative cooling cycle, and allows the gain of 105 in phase space density necessary to achieve quantum degeneracy.