Quantum Optics Seminar: Lena Hansen, PhD Candidate, University of Vienna

Non-classical excitation of a solid-state quantum emitter

The interaction between one atom and one photon constitutes the most fundamental instance of quantum optics. A quantum light-matter platform that allows for such an elementary interaction permits the study of various quantum processes, including atom-mediated single-photon scattering and effective photon-photon interactions. Here, we demonstrate the resonant excitation of a two-level quantum emitter using quantized input light. For this genuine quantum lightmatter interaction, we observe coherent scattering involving the absorption and re-emission of one photon, optical non-linearities occurring at the one-photon level, and stimulated emission processes. Furthermore, we theoretically reproduce our observations using a cascaded master equation model. Our findings demonstrate a solid-state platform where one photon is sufficient to change the state of an atom, and efficient atom-mediated photon-photon interactions are feasible. These results suggest future possibilities ranging from enabling quantum information transfer in a quantum network to building deterministic entangling gates for photonic quantum computing.