Large Momentum Separation Matter Wave Interferometry

Abstract

This work establishes a new benchmark for momentum separation in a matter wave interferometer with stable, visible fringes. With a path separation of 112 photon recoil momenta, our signal visibility of 30% and phase stability of 0.6rad exceed the performance of earlier free space interferometers. Contributing to this success are the symmetric form of the 3 path contrast interferometer geometry, which rejects phase noise due to vibrations and other systematic errors, the narrow momentum width of the Bose-Einstein condensate (BEC) source, and atom-optics parameters chosen to suppress unwanted diffraction phases. These results can be applied toward a competitive measurement of the fine-structure constant and a test of QED. The described experiments were performed in a new ytterbium BEC apparatus whose design, construction, and operation is documented here.