Room-Temperature Strong Coupling between CdSe Nanoplatelets and a Metal-DBR Fabry–Pérot Cavity

We present the generation of exciton-polaritons in CdSe nanoplatelets (NPLs) at room temperature in a metal-dielectric hybrid cavity. The optical cavity is packed with NPLs devoid of any spacer, allowing a larger population of emitters to couple to the cavity. The NPL-filled cavity system shows a Rabi splitting of 74.5 meV compared to the previously obtained 41.5 meV Rabi splitting with an NPL-in-PMMA cavity at room temperature. Angle-resolved reflectance and photoluminescence measurements are performed to explore the polariton photophysics by varying the cavity-exciton detuning and temperature. The role of dark states as a reservoir in redistributing polariton populations is also investigated. Mixed quantum-classical dynamics calculations are performed to model the polariton system wherein the theoretical simulations agree with the experimental observations, providing a fundamental understanding of the polariton dynamics within the NPL-cavity hybrid system. These room-temperature exciton-polaritons have the potential to unlock new chemical reaction pathways as well as pave the way for developing cutting-edge quantum technologies.