Benchmarking cavity lattices via atomic clock shifts

We have developed ultra-high-vacuum compatible cavities to create large-scale, two-dimensional optical lattices for use in experiments with ultracold atoms. The assembly consists of an octagon-shaped spacer made from ultra-low-expansion glass, to which we optically contact cavity mirrors, leading to a high degree of mechanical and thermal stability. The advantages of such cavities include increasing the system sizes in quantum gas microscopes by an order of magnitude compared to the state-of-the-art, improving the lattice homogeneity, and enhancing the lattice depth. We have integrated the cavities into an ultracold Strontium machine and benchmarked the size and homogeneity of the lattice by imaging the intensity profile via atomic clock shifts. Our clock spectroscopy can also locally resolve the vibrational modes, thus allowing us to locally probe temperatures. We do not observe discernible heating while holding the atoms in the lattices up to 15 seconds, and we observe atom lifetime of a minute. Our results present a viable solution to create ultracold atoms experiments where compactness, stability, and large, deep lattices can be achieved simultaneously.