Quantum reflection of metastable neon atoms on solid surface

Summary form only given. A thermal atom approaching a solid surface is usually pulled by the attractive van der Waals potential, hit the surface and is scattered or adsorbed. For an extremely cold atom, however, the spatial variation of the van der Waals potential is sufficiently steep to cause impedence mismatch of the atomic wave approaching the surface. As a result the atom is reflected back specularly at a distance far from the surface. This phenomenon, quantum reflection, has been theoretically predicted, and indirect evidences have been observed on superfluid helium surface. We report the first observation of the quantum reflection on a solid surface. Laser-cooled metastable neon atoms were hit on a silicon surface at a shallow angle, and the reflectivity was measured at normal incident velocity below 30mm/s. The reflectivity was approximately 10% at 3mm/s.