Abstract

Standing wave laser fields produce a periodic potential for atoms, that can trap cold atoms in an ordered crystal-like structure.¹ While in most optical lattices studied so far near resonant light is used, where spontaneous emission limits the atomic coherence time, we explore optical lattices relying on the far-detuned 10.6 μm radiation of a CO₂-laser. We have trapped rubidium atoms in the antinodes of a standing wave generated from this laser. The spontaneous scattering rate is one photon per atom in 20 minutes. The lattice period equals approximately 7 times the excitation wavelength of the lowest electronic resonance. On the other hand, the vibrational frequency of the trapped atoms along the standing wave axis exceeds the photon recoil, such that the Lamb-Dicke limit is fulfilled.

© 1998 IEEE