Comparison of loading double-loop microtraps from a surface MOT and a FORT

Two methods to load a microtrap consisting of two concentric microwire loops of radii 300 and 660 mu m carrying oppositely oriented currents are demonstrated. Atoms can be directly loaded into the microtrap from a surface magneto-optical trap or alternatively using a far-off resonance optical dipole trap (FORT) as an intermediate step. About 1 x 10(5) Rb-87 atoms can be loaded into the microtrap using either technique although the FORT achieves a lower temperature. The FORT is well suited to loading a linear array of 3 microtraps that are aligned with the propagation direction of the infrared laser. Atoms can be trapped in either the or 2 ground state hyperfine level. The position of the microtrapped atom cloud can be precisely adjusted using a bias magnetic field over a distance of 350 to slightly < 50 mu m from the atom chip surface.