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

We describe an all-optical method of making a ${}^{87}\mathrm{Rb}$ Bose-Einstein condensate (BEC). Atoms are first cooled in an optical lattice and loaded into a crossed dipole trap with $1.06\mu \mathrm{m}$ light. Then the density is increased by dynamically reducing the trap size, while the atoms are evaporatively cooled by reducing the light intensity. Every $3.3\mathrm{s}$, we obtain a nearly pure BEC with $3.5\times {10}^5$ atoms in their lowest internal energy state.