All-optical formation of an atomic Bose-Einstein condensate

We have created a Bose-Einstein condensate (BEC) of 87Rb atoms directly in an optical trap. We employ a quasielectrostatic dipole force trap formed by two crossed CO2 laser beams. Loading directly from a sub-Doppler laser-cooled cloud of atoms results in initial phase space densities of approximately 1/200. Evaporatively cooling through the BEC transition is achieved by lowering the power in the trapping beams over approximately 2 s. The resulting condensates are F = 1 spinors with 3.5x10(4) atoms distributed between the m(F) = (-1,0,1) states.