Laser cooling in a CO2-laser optical lattice

We report on the trapping of laser-cooled rubidium atoms in the antinodes of an infrared standing wave near 10.6 mu m. Intriguing properties of the resulting optical lattice are long coherence times and a large lattice period. We have experimentally verified the localization of the atoms in the antinodes of the standing wave field by measurement of the vibrational spectrum of the atoms. The phase-space density of the trapped atoms, cooled by optical means only, is less than three orders of magnitude below the threshold of Bose-Einstein condensation.