  Using a three-path contrast interferometer (CI) geometry and laser-pulse
diffraction gratings, we create the first matter-wave interferometer with
ytterbium (Yb) atoms. We present advances in contrast interferometry relevant
to high-precision measurements. By comparing to a traditional atom
interferometer, we demonstrate the immunity of the CI to vibrations for long
interaction times (> 20 ms). We characterize and demonstrate control over the
two largest systematic effects for a high-precision measurement of the fine
structure constant via photon recoil with our interferometer: diffraction
phases and atomic interactions. Diffraction phases are an important systematic
for most interferometers using large-momentum transfer beam splitters; atomic
interactions are a key concern for any BEC interferometer. Finally, we consider
the prospects for a future sub-part per billion photon recoil measurement using
a Yb CI.
