Enhancement of Sisyphus cooling using a bichromatic standing wave - art. no. 035401

We show that Sisyphus cooling in a one-dimensional gray optical lattice can be improved by using a bichromatic standing wave that increases the effici ency of cooling as compared to typical lattices. Using the time of flight t echnique to determine the velocity distribution of all the atoms, we calcul ate the efficiency by measuring the fraction of all atoms that are cooled b y the lattice. We show that the efficiency depends on the relative displace ment between the two standing waves formed by the two colors. The optimal c onfiguration of the bichromatic light field yields a 40% improvement in eff iciency compared to typical optical lattices, while maintaining the same at omic temperature.