Magnetic whispering-gallery mirror for atoms

Videotape with a sinusoidal magnetization of $31\hspace{0.5em}\mu \mathrm{m}$ wavelength is used to reflect Cs atoms with unit reflectivity in a 75 m/s atomic beam. The atoms serve as a probe, allowing us to measure the magnetic field at the surface. A technique is presented for mounting the videotape so that its surface can be curved to a specific shape or made flexible. We show that such a reflector provides high-quality grazing-incidence atom optics and we demonstrate deflections as large as $23°$ in a whispering-gallery geometry.