Towards a programmable quantum light-matter interface with strontium atom arrays

We report progress on the construction of an experiment to study and control cooperative radiative effects between ultracold strontium atoms trapped in ordered arrays. Our primary goal is to deterministically assemble these atoms into photonic crystals, and thereby access a new regime of quantum electrodynamics (QED). In particular, we aim to harness the phenomenon of subradiance in subwavelength atomic arrays to engineer waveguides, cavities, and metasurfaces. In a subradiant state, photons are trapped as spin-wave excitations within the atom array, which forms a highly nonlinear dielectric. This nonlinearity represents a departure from the familiar bosonic excitations in conventional cavity and waveguide QED, and can be harnessed to develop new techniques for controlling single photons. Our apparatus is specifically designed to access subradiant physics by targeting mid-infrared transitions from the metastable states in the 5s5p ³P_J manifold of strontium, for which subwavelength trapping is readily accessible.  This work will pave the way for integration of a highly programmable and coherent light-matter interface with neutral atom arrays for quantum networks, computing, and many-body physics.