Spatial tomography of individual atoms in a quantum gas microscope

We demonstrate a method to determine the position of single atoms in a three-dimensional optical lattice. Atoms are sparsely loaded from an far-off-resonant optical tweezer into a few vertical planes of a cubic optical lattice positioned near a high-resolution microscope objective. In a single realization of the experiment, we pin the atoms in deep lattices and then acquire multiple fluorescence images with single-site resolution. The objective is translated between images, bringing different vertical planes of the lattice into focus. In this way, we tomographically reconstruct the atom distribution in three dimensions. This opens up the possibility of extending the domain of quantum simulation using quantum gas microscopes from two to three dimensions.