Optical lattices for atomic fountain frequency standards

Atomic fountain frequency standards require extremely low temperature atomic samples. Laser cooling of neutral atoms has achieved temperatures of a few microkelvin, but even such low temperatures still present difficulties. Here we report laser cooling in an optical lattice, along with cooling by adiabatic expansion, that gives a temperature of 0.7 /spl mu/K. Such low temperatures should improve the performance of atomic fountain frequency standards.>