Controlling light-matter interaction at the single-quantum level is a long-standing goal in optical physics, with applications to quantum optics and quantum information science. However, single photons usually do not interact with each other and the interaction needs to be mediated by an atomic system. Enhancing this coupling has been the driving force for a large community over the past two decades. In contrast to the cavity-QED approach where the interaction is enhanced by a cavity around the atoms, strong transverse confinement in single-pass nanoscale waveguides recently triggered various investigations for coupling guided light and cold atoms. Specifically, a subwavelength waveguide can provide a large evanescent field that can interact with atoms trapped in the vicinity. An atom close to the surface can absorb a fraction of the guided light as the effective mode area is comparable with the atom cross-section. This emerging field known as waveguide-QED promises unique applications to quantum networks, quantum non-linear optics and quantum simulation. Recently, the LKB team pushed the field for the first time into the quantum regime by creating an entangled state of an array of atoms coupled to such a waveguide. Two experiments are dedicated to this waveguide-QED effort and internships/PhD projects are proposed on both of them.