Cavity-aided magnetic-resonance imaging of atoms in optical lattices

Microscopic imaging is a powerful tool for measuring cold-atom systems, enabling the readout of ultracold atomic simulators and registers, the characterization of inhomogeneous environments, and the determination of spatially varying thermodynamic quantities. Single-optical-lattice-site microscopy has recently been demonstrated, using fluorescence and ionization imaging. However, these methods destroy the quantum states being measured and have limited dynamic range. Here we demonstrate single-lattice-site imaging using magnetic-resonance imaging, enabled by using a high-finesse cavity for spin measurement. The images are state sensitive and have 150~nm spatial resolution. We measure atoms with high dynamic range, sensing up to 1000 atoms in single lattice sites with a sensitivity of $\pm 10$ atoms, or a sensitivity of $\pm 2.4$ for up to 70 atoms. We apply this technique to measure the nonequilibrium transport dynamics of the atoms, observing the onset of interaction-inhibited transport in a nondegenerate gas.