Surface Trap for Cs atoms based on Evanescent-Wave Cooling

Abstract

We demonstrate a gravito-optical surface trap for Cs atoms which exploits cooling in an evanescent light wave. About 1${0}^{5}$ atoms were cooled down to 3 \ensuremath{\mu}K and formed a sample with a mean height of $\ensuremath{\sim}20\ensuremath{\mu}\mathrm{m}$ above the surface of a dielectric prism. The trap does not use a magnetic field and leads to very small atomic level perturbations. The excited-state population of the stored atoms is $\ensuremath{\sim}1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and collisional losses are strongly suppressed.