Exciton–polariton condensation in MAPbI ₃ films from bound states in the continuum metasurfaces

Exciton-polariton condensation in optical resonators is a fascinating pathway to realise ultra-coherent states of light, underpinned by Bose-Einstein quasiparticles. Bearing inherently non-radiative nature, bound states in continuum (BIC) have proven to be an excellent platform to achieve polariton condensation. Here, we report exciton-polariton condensation in a solution-processed perovskite thin film hybridized with a silicon BIC metasurface. Thanks to the high quality factor of the BIC, the polariton condensation exhibits low fluence threshold, narrow linewidth, and large spatial and temporal coherence. These results demonstrate the feasibility of integration of perovskite polaritonic devices in scalable silicon photonic platforms.