Abstract
Despite great efforts and long-lasting interest in foundational quantum optics, we still learn from surprisingly simple systems: a two-level system coupled to an optical cavity. In this talk, I will present two recent studies which finely resolve the dynamical response of such a quantum emitter to a classical or non-classical input field. The experiments reveal spectro-temporal correlations, single-photon interference and stimulated emission triggered by an individual photon. Beyond their fundamental interest, these results directly impact photonic quantum technologies, e.g. by demonstrating methods that restore high single-photon purities even for strongly Purcell-enhanced emission. Although the quantum system is conceptually simple, studying these effects experimentally requires a highly efficient light-matter interfaces. In our work, we use semiconductor quantum dots embedded in a dielectric cavity. This architecture creates exceptional sources for quantum light and has become a promising platform to realize quantum nonlinearities through emitter-mediated photon-photon interactions.
