Properties of microelectromagnet mirrors as reflectors of cold Rb atoms

Cryogenically cooled microelectromagnet mirrors were used to reflect a clou d of free-falling laser-cooled Rb-85 atoms at normal incidence. The mirrors consisted of microfabricated current-carrying Au wires in a periodic serpe ntine pattern on a sapphire substrate. The fluorescence from the atomic clo ud was imaged after it had bounced off a mirror. The transverse width of th e cloud reached a local minimum at an optimal current corresponding to mini mum mirror roughness. A distinct increase in roughness was found for mirror configurations with an even versus odd number of lines. These observations confirm theoretical predictions. [S1050-2947(99)08711-9].