Background-free imaging of an atom array integrated with a nanophotonic chip

Single-shot, site-resolved fluorescence readout is a crucial component of the toolkit for atom arrays in optical tweezers, which have become a leading platform for quantum information science. However, recent efforts to integrate atom arrays with nanophotonic interfaces have prompted the need for alternative readout mechanisms since scattering from the nanophotonic devices easily outshines atomic fluorescence signals at the few-photon level. Here, we present our recent results on integrating an atom array with a millimeter scale chip containing over one hundred nanophotonic cavities and introduce a background-free, multichromatic fluorescence imaging scheme. This imaging technique allows us to spectrally filter out scattering of the drive lasers from the chip and achieve single-shot fluorescence imaging of atoms trapped close to as well as on top of the photonic chip. We verify that the atoms are loaded onto the nanocavities via Stark shift measurements of the modified trapping potential. We also demonstrate rearrangement into defect-free arrays and load these arrays onto the cavities. These results are an enabling step towards integrating atom arrays into quantum networks as well as realizing new approaches to quantum simulation with engineered atom-photon and atom-atom interactions via coupling to nanophotonic devices.