Strong light-matter coupling in dielectric metasurfaces

We demonstrate the strong coupling between excitons in organic molecules and all-dielectric metasurfaces formed by arrays of silicon nanoparticles supporting Mie surface lattice resonances (MSLRs). Compared to Mie resonances in individual nanoparticles, MSLRs have extended mode volumes and much larger quality factors, which enables to achieve collective strong coupling with very large coupling strengths and Rabi energies. Moreover, due to the electric and magnetic character of the MSLR given by the Mie resonance, we show that the hybridization of the exciton with the MSLR results in exciton-polaritons that inherit this character as well. Our results demonstrate the potential of all-dielectric metasurfaces as novel platform to investigate and manipulate exciton-polaritons in low-loss polaritonic devices.