Matter-wave interference in an axial triple-well optical dipole trap

Abstract

This paper proposes a scheme of axial triple-well optical dipole trap by employing a simple optical system composed of a circular cosine grating and a lens. Three optical wells separated averagely by ∼37 μm were created when illuminating by a YAG laser with power 1 mW. These wells with average trapping depth ∼0.5 μK and volume ∼74 μm3 are suitable to trap and manipulate an atomic Bose–Einstein condensation (BEC). Due to a controllable grating implemented by a spatial light modulator, an evolution between a triple-well trap and a single-well one is achievable by adjusting the height of potential barrier between adjacent wells. Based on this novel triple-well potentials, the loading and splitting of BEC, as well as the interference between three freely expanding BECs, are also numerically stimulated within the framework of mean-field treatment. By fitting three cosine functions with three Gaussian envelopes to interference fringe, the information of relative phases among three condensates is extracted.