Dissipative transfer of quantum correlations from light to atomic arrays

We show how the directional collective response of atomic arrays to light can be exploited for the dissipative generation of entangled atomic states, relevant for, e.g., quantum metrology. We consider an atomic array illuminated by a paraxial beam of a squeezed-vacuum field and demonstrate that quantum-squeezing correlations are dissipatively transferred to the array atoms, resulting in an atomic spin-squeezed steady state. We find that the entanglement transfer efficiency and hence the degree of spin squeezing are determined by the resonant optical reflectivity of the array. Considering realistic cases of finite-size array and illuminating beam, we find how the spin-squeezing strength scales with system parameters, such as the number of layers in the array and its spatial overlap with the beam. We discuss applications in atomic clocks in both optical and microwave domains.