Atom Wave Interferometry with Diffraction Gratings of Light

We have developed a novel interferometer for atom de Broglie waves, where amplitude division and recombination is achieved by diffraction at standing light waves operating as phase gratings. Our new atom interferometer is the exact mirror image of interferometers for light, with the roles of atoms and photons interchanged, and it directly demonstrates coherence of the diffraction of atomic waves at standing light waves. Easy manipulation of the phase, intensity, and polarization of the standing light wave permits novel studies of atomic coherence properties.