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 1s₅ (J0ex{0ex}=0ex{0ex}2) and optically pumped to the state 1s₃ (J0ex{0ex}=0ex{0ex}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.