Surface Trap for Cs atoms based on Evanescent-Wave Cooling

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 μK and formed a sample with a mean height of $\sim 20\mu \mathrm{m}$ 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 $\sim 1.5\times {10}^{-6\mathrm{}}$ and collisional losses are strongly suppressed.