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 ${1s}_5(J=2\mathrm{}$) and optically pumped to the state ${1s}_3(J=0\mathrm{}$). 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.