Atoms in the lowest motional band of a three-dimensional optical lattice

We investigate the storage of atoms in an optical lattice, using light detuned up to 2 nm to the blue of an atomic transition. Argon atoms were laser cooled in the metastable state 1s(5)(J = 2) and optically pumped to the state 1s(3)(J = 0). Subsequently these atoms were confined to the nodes of a three-dimensional interference pattern and stored for up to 1 s. We resolved the bands of motion in the lattice using a time-of-flight technique, and observed band-dependent losses leading to the preparation of atoms in the motional ground band.