Observation of a coherence loss of an atomic wave scattered from the optical potential in a Talbot-Lau atom interferometer

A coherence loss of an atomic wave scattered from the optical potential in an interferometer is observed. A Talbot-Lau atom interferometer is developed for that measurement using a laser-cooled lithium atomic beam. The long de Broglie wavelength of slow lithium atoms gives a short Talbot length and makes it possible to construct a small and stable atom interferometer.