Cavity QED with an atom tweezer array

Using an apparatus consisting of an optical cavity and a tweezer array of ⁸⁷Rb atoms, we demonstrate mid-circuit cavity measurement and collective atomic scattering dynamics. We first present results on mid-circuit measurement in a neutral atom tweezer array. After preparing the tweezer array, we bring single atoms one at a time into a high-finesse optical cavity and perform either fluorescence- or transmission-based readout. To demonstrate mid-circuit measurement, we initialize a two-atom array and perform a microwave Ramsey sequence, with cavity measurement of the first atom in between pulses on the second atom, and show that the second atom’s coherence is unperturbed by the first atom measurement. We have extended our cavity readout capabilities to studying the collective scattering of multiple atoms in a cavity. Probing the atoms transversely to the cavity, we resolve the spatial structure of the cavity standing wave through the spatial dependence of atomic fluorescence as we scan the atom positions. We show constructive and destructive interference based on the relative positions of the atoms due to the phase of the cavity field at each atom. We also observe a collectively enhanced, super-linear scaling of the cavity photon number with the number of atoms in the cavity and study this behavior at probe detunings near and far from atomic resonance. Lastly, we discuss prospects for observing self-organized atom configurations due to the collective buildup of the cavity field by using cavity readout and fluorescence imaging to indicate atom localization.