In situ measurement of the wavefront phase shift in an atom interferometer

Abstract

Wavefront aberrations have significant impacts on the accuracy and long-term stability of cold-atom interferometers. This research presents an in situ method for directly measuring the phase shift induced by the wavefront of the Raman beam using the atom interferometer itself. To validate the feasibility of this approach, experiments involving the insertion of a glass plate with a known surface figure into the Raman beam path have been carried out. The phase introduced by the glass plate is measured experimentally by the atom interferometer and calculated theoretically based on the wavefront obtained from the wavefront sensor, and we find good agreement of the experimental results with the theoretical calculations. The method not only allows for the assessment of systematic errors in an atom interferometer, but also provides the capability to retroactively compute the wavefront of Raman beams based on the measured phase shift. The wavefront distribution of the glass plate is inversed from the phase measured by the atom interferometer. This inversed wavefront distribution is consistent with the surface of the glass plate measured by the wavefront sensor, which confirms the effectiveness of the method. This work provides a valuable approach to evaluate the systematic errors in atom interferometers that are sensitive to wavefront aberrations. Furthermore, it offers a novel method to measure the wavefront using atoms.