High-density cooling of cesium atoms in the gravito-optical surface trap

Abstract

Summary form only given. The gravito-optical surface trap (GOST) confines cesium atoms by a blue-detuned repulsive evanescent wave (EW) in combination with gravity. Horizontal confinement is provided by the conservative optical dipole potential of a hollow, cylindrical laser beam, far blue-detuned from resonance. For preparing a very cold and dense cesium gas in the GOST, we use evanescent wave 'Sisyphus' cooling, which is based on inelastic reflections of the atoms from the EW. Using this method we have obtained a temperature of 3 /spl mu/K, which corresponds to an average distance of the atoms from the surface of 19 /spl mu/m. As a very important feature for attaining very high densities, EW cooling allows one to keep the atoms predominantly in the absolute ground state, thus avoiding trap loss by light assisted collisions.