Light-matter interactions are at the heart of quantum electrodynamics and underpin modern photonic technologies. As we develop means to control the properties of light, matter and their interactions, intriguing new phenomena emerge.  Using a designer polariton platform we have developed, we reveal a long sought after Bardeen-Cooper-Schrieffer like phase in a particle-hole-photon strongly-coupled system. Coupling two trapped polariton condensates through both coherent tunneling and incoherent dissipation, we form a model system of rich nonlinear dynamics where new, equidistant frequency lines emerge via the limit cycles at Hopft bifurcation.  The discovery of van der Waals semiconductors have furthermore opened up new opportunities of controlling light-matter interactions, from strong-coupling with fully designable photonic crystals to collective Lamb shift and perfect absorption in free-space. Stacking different monolayers to form atomically-thin heterostructures, we obtain a platform that allows control over also the matter excitations, where we create long-lived valley excitons, ultra-thin lasers, and moire-polaritons with nonlinearity enhanced by quantum confinement. In the future, controlling both light and matter using the van der Waals semiconductor system may allow creating photonic systems with extreme performances or exotic spatial-temporal symmetries.