Characterization of an atom interferometer in the quasi-Bragg regime
Résumé
We provide a comprehensive study of ultracold-atom diffraction by an optical lattice. We focus on an intermediate regime between the Raman-Nath and Bragg regimes, the so-called quasi-Bragg regime. The experimental results are in good agreement with a full numerical integration of the Schrödinger equation. We investigate the long-pulse regime limited by a strong velocity selection and the short-pulse regime limited by “nonadiabatic losses.” For each of these regimes, we estimate the multiport features of the Bragg interferometers. Finally, we discuss the best compromise between these two regimes, considering the diffraction phase shift and the existence of parasitic interferometers.