Towards single-site imaging of an erbium quantum gas microscope

Single-site imaging of atoms in optical lattices is a powerful way of studying quantum systems. We present updates on an erbium quantum gas microscope, which features a high-resolution imaging system, a low-disorder optical lattice, and an accordion lattice with tunable spacing. High-resolution imaging is realized via a custom, in-vacuum objective (numerical aperture = 0.9) with diffraction-limited performance across a large field of view. To minimize disorder in the lattice potential, the objective features a hole along the optical axis so that a beam can go through the objective and then be retro-reflected from a mirror many Rayleigh lengths away from the atoms. The accordion lattice, projected through the objective, features galvanometers and interferometrically aligned beam splitter prisms to manipulate the lattice spacing from 266 nm to more than 5 um. Such tunability helps to increase imaging fidelity, allows for spin-resolved imaging of many spin states in a single shot, and may also be used to study the cooperative resonances of two-dimensional atom arrays in quantum optics and optomechanics. Overall, these features make the experiment an ideal platform for next-generation quantum gas microscopy and pave the way for quantum simulation of ultracold atoms in optical lattices with long-range interactions.