Evaporative cooling of 87Rb atoms into Bose-Einstein condensate in an optical dipole trap

We create a Bose-Einstein condensate (BEG) of Rb-87 atoms by runaway evaporative cooling in an optical trap. Two crossed infrared laser beams with a wavelength of 1064 nm are used to form an optical dipole trap. After precooling the atom samples in a quadrupole-Ioffe configuration (QUIC) trap under 1.5 mu K by radio-frequency (RE) evaporative cooling, the samples are transferred into the center of the glass cell, then loaded into the optical dipole trap with 800 ms. The pure condensate with up to 1.5x10(5) atoms is obtained over 1.17 s by lowering the power of the trap beams.