Talbot-vonLau atom interferometry with cold slow potassium

Abstract

A dc hot thermal and an ac-modulated cold slow potassium beam copropagate and pass through an atom de Broglie--wave interferometer, consisting of a sequence of three microfabricated diffraction gratings. Talbot-vonLau interference fringes are formed and sensed by measuring transmission with a hot wire as a function of grating position. The hot beam produces diffraction-limited shadow Moir\'e fringes, while the longer de Broglie wavelength slow beam produces interference fringes with high visibility at the fifth and sixth spatial harmonics of the shadow Moir\'e fringes.