In Situ Wavefront Mapping for Absolute Atom Interferometry

Wavefront distortions are a leading source of systematic uncertainty in light-pulse atom interferometry. We present recent measurements showing isolation and in situ characterization of the wavefront curvature in an atom interferometer as well as other transverse-motion based biases. Finite-size effects impact the measured transverse spatial phase bias profiles. Corrections and phase offsets are shown in the case of low-order Zernike wavefronts, and we demonstrate measurement and correction of the wavefront phase bias at the mrad-level in the presence of controlled wavefront curvature. This measurement process could be adopted in optimized atom interferometer gravimeters/accelerometers to reduce the wavefront bias uncertainty below the nm/s² level.