Optical Dipole Trap for Ultracold Atoms Loaded from Dark SPOT

In this work, we load a 1070 nm crossed optical dipole trap (ODT) from a 133Cs dark spontaneous emission optical trap. Obvious improvements in the loading rate and atomic lifetime are demonstrated, comparing with the values of the atoms which are loaded directly from a normal magneto-optical trap. We analyze the atomic number as a function of time in the ODT’s loading and holding processes based on the constant density and the constant volume approximations, respectively. We also demonstrate that the atomic temperature in holding process is related to the atomic collision, which consists of two-body collision and background gas induced collision. Finally the relationship between atomic collision and optical trap depth is measured and analyzed. The atomic loading way we present can be easily expanded to other species to obtain an atomic sample with large number and high density.