Production of 87Rb Bose-Einstein Condensate with a Simple Evaporative Cooling Method

A Bose-Einstein condensate with a large atom number is an important experimental platform for quantum simulation and quantum information research.An optical dipole trap is the a conventional way to hold the ultracold atoms,where an atomic cloud is evaporatively cooled down before reaching the Bose-Einstein condensate.Acarefully designed trap depth controlling curve is typically required to realize the optimal evaporation cooling.We present and demonstrate a simple way to optimize the evaporation cooling in a crossed optical dipole trap.A polyline shape optical power control profile is easily obtained with our method,by which a pure Bose-Einstein condensate with atom number 1.73 × 105 is produced.Theoretically,we numerically simulate the optimal evaporation cooling using the parameters of our apparatus based on a kinetic theory.Compared to the simulation results,our evaporation cooling shows a good performance.We believe that our simple method can be used to quickly realize evaporation cooling in optical dipole traps.