All-optical Bose-Einstein condensation using a compressible crossed dipole trap

We describe an all-optical method of making a ⁸⁷Rb Bose-Einstein condensate (BEC). Atoms are first cooled in an optical lattice and loaded into a crossed dipole trap with 1.060.3em0exμm light. Then the density is increased by dynamically reducing the trap size, while the atoms are evaporatively cooled by reducing the light intensity. Every 3.30.3em0exs, we obtain a nearly pure BEC with 3.5×10⁵ atoms in their lowest internal energy state.