Direct Measurement of Atom-Surface Induced Phase Shifts with an Atom Interferometer

Ch. Antoine, Ch. J. Bordé

Wen-Jie Xu, Jie Liu, Qin Luo +2 more

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.

M Büchner

John D. Perreault, Alexander D. Cronin

The development of nanotechnology and atom optics relies on understanding how atoms behave and interact with their environment. Isolated atoms can exhibit wavelike (coherent) behavior with a corresponding de Broglie wavelength and phase which can be affected by nearby surfaces. Here an atom interferometer is used to measure the phase shift of Na atom waves induced by the walls of a 50 nm wide cavity. To our knowledge this is the first direct measurement of the de Broglie wave phase shift caused by atom-surface interactions. The magnitude of the phase shift is in agreement with that predicted by Lifshitz theory for a nonretarded van der Waals interaction. This experiment also demonstrates that atom waves can retain their coherence even when atom-surface distances are as small as 10 nm.

John D. Perreault, Alexander D. Cronin

The interaction of Na atoms with a surface was probed by inserting a nanofabricated material grating into one arm of an atom interferometer (IFM). This technique permits a direct measurement of the change in phase and coherence of matter waves as they pass within 25 nm of the grating bar surface. The practical concerns and challenges of making such a measurement are discussed here. Interference of spurious diffraction orders, IFM path overlap, and the partial obscuration of IFM beams are all important aspects of this experiment. The systematic effects that contribute to the measured phase shift and contrast are discussed.

Vincent Lonij, Alex D. Cronin, S. Lepoutre +4 more