Strong light–matter coupling and exciton-polariton condensation in lattices of plasmonic nanoparticles

Arrays of metallic nanoparticles support collective plasmonic resonances known as surface lattice resonances (SLRs). The strong and delocalized electromagnetic fields associated with SLRs provide an excellent platform for experiments within the realm of light–matter interaction. The planar architecture of these arrays also provides a feasible system for coupling to different materials. One of the areas where SLRs have demonstrated their potential is strong light–matter coupling, with possible applications in nonlinear optics, coherent light generation, photochemistry, and optoelectronics. In this perspective, we describe how SLRs are formed in arrays of plasmonic nanoparticles, introduce different materials used for strong coupling with SLRs, discuss some experiments that demonstrate the nonlinear emission of strongly coupled organic molecules with SLRs, and give our vision on future research directions of strongly coupled SLRs with organic molecules.