Metallic and dielectric nanoparticles behave as resonators with resonant frequencies determined by their size, shape, and composition. When these resonators are placed in periodic arrays, they can radiatively couple through in-plane diffraction orders, forming non-local metasurfaces with collective modes called surface lattice resonances (SLRs). SLRs lead to large field enhancements over extended areas, offering an ideal platform for strong-light matter coupling and optoelectronic applications. In this presentation, I will discuss the coupling of SLRs with excitons in organic molecules to form exciton-polaritons (EPs). EPs can condense to the ground state, leading to a coherent emission known as polariton lasing. The threshold for condensation depends on the different mechanisms assisting the relaxation of excitons to EPs, and the optical losses of SLRs, which can be controlled through the choice of materials and the symmetries in the system. Vortex emission is achieved at a very low threshold from symmetry-protected bound states in the continuum.
|