Bose-Fermi mixtures naturally appear in various physical systems. In van der Waals heterostructures, such mixtures can be realized, with bosons as excitons and fermions as dopant charges. This opens the opportunity to use excitons as sensors of electronic correlations. I will discuss experimental results obtained during my previous positions at the Joint Quantum Institute and the University of Geneva. We showed how optical exciton diffusion can benchmark the formation of correlated states in a moir\'e structure and how the strong particle-particle interactions in this system can lead to collective emission. I will finish by presenting some perspectives for our recently formed group at UMBC: the Group of Quantum Optics of Correlated Materials. We will use techniques from the quantum optics field to investigate multi-electronic correlations that emerge from strong particle-particle interactions.