Polariton–polariton interactions in microcavities with 2D Perovskites

Hybrid light–matter systems based on metal–halide perovskites offer a versatile platform for realizing nonlinear photonic and quantum functionalities at ambient conditions. Their strong excitonic resonances and structural tunability enable pronounced optical nonlinearities at low excitation powers. Here, we demonstrate the emergence of exciton–polaritons and their interaction-induced energy shifts in a layered perovskite thin film embedded within a microcavity. Under optical excitation, a distinct blueshift of the lower polariton branch is observed, reflecting the strength of the underlying polaritonic interactions. This highlights the potential of perovskite-based microcavities for room-temperature implementation of nonlinear and reconfigurable photonic elements, including optical logic, switching, and neuromorphic computing architectures. Structural and optical characterizations confirm high-quality film formation and well-defined cavity modes, achieved through solution processing and standard thin-film deposition techniques.