Tightly packed ordered arrays of atoms (or, more generally, quantum emitters) exhibit remarkable collective optical properties, as dissipation in the form of photon emission is correlated. In this talk, I will discuss the single-, few- and many-body out-of-equilibrium optical physics of atomic arrays, and their potential to realize versatile light-matter interfaces. In particular, I will focus on subradiance (where atoms are “dark” and become decoupled from the radiative environment) and on its counterpart, superradiance (where atoms are “bright” and radiate much faster than a single atom would). I will finish by discussing the implications of collective light matter interaction in quantum information processing, non-linear optics, and metrology.
