Experimental demonstration of controllable double magneto-optical traps on an atom chip

We demonstrate controllable double magneto-optical traps (DMOTs) on an atom chip: At first, DMOTs, which trap atoms directly from the background rubidium vapor in an ultrahigh-vacuum environment, are realized on an atom chip simultaneously. The double quadrupole magnetic fields are produced by two separate U-shaped microwires on the atom chip, combined with a bias magnetic field. Then, we determine the best parameters for a U-shaped magneto-optical trap (UMOT) through a detailed comparison of the capture ability at different currents and the bias magnetic field between two different geometric sizes of UMOT. Finally, we demonstrate the mixing and splitting of the DMOTs on the atom chip with the help of an extra pair of anti-Helmholtz coils. © 2008 Optical Society of America.