Cooperative quantum-optical planar arrays of atoms

Atomic planar arrays offer a novel emerging quantum-optical many-body system in which light mediates strong interactions between the atoms. The regular lattice structure provides a cooperatively enhanced light-matter coupling and allows for increased control and harnessing of these interactions. In subwavelength arrays, coherent scattering of incident light beams can be highly collimated in the forward and backward direction, resembling one-dimensional light propagation without the need for waveguides, fibers, or resonators. The atomic planar arrays share features with fabricated metasurfaces, formed by thin nanostructured films that have shown great promise in manipulating and structuring classical light. Here we describe theoretical methods commonly employed to analyze the cooperative responses of atomic arrays and explore some recent developments and potential future applications of planar arrays as versatile quantum interfaces between light and matter.