Realization of bichromatic optical superlattices - art. no. 011401

We present the experimental realization of optical superlattices created by exposing laser cooled Rb-85 atoms to a bichromatic standing-wave light hel d. The two light frequencies are tuned close to the D-1 and D-2 lines of Rb -85. The total optical potential seen by the atoms exhibits a modulation at the spatial beat period of the two light fields in addition to the typical periodicity on the scale of an optical wavelength. The bichromatic light f ield cools the atoms into the superlattice potential, resulting in a densit y modulation on a macroscopic scale. We have observed the density modulatio n directly in one- and three-dimensional superlattice configurations using an absorption imaging technique.