Matter wave interference of single trapped atoms

Single neutral atoms trapped in an optical lattice form an ideal system for the investigation of coherent matter wave phenomena in a well controlled way. For this it is necessary to coherently manipulate and detect the system with a spatial resolution better than the periodicity of the optical lattice (λ/2 = 433 nm). We have realized such a system by trapping single laser cooled Caesium atoms in a spin dependent optical lattice. High resolution fluorescence imaging yields precise detection of atomic positions even down to nearest neighbors in the lattice [1].