Collective resonances in plasmonic crystals: Size matters

Periodic arrays of metallic nanoparticles may sustain Surface Lattice Reso-nances (SLRs), which are collective resonances associated with the diffractive coupling of Localized Surface Plasmons Resonances (LSPRs). By investigat-ing a series of arrays with varying number of particles, we traced the evolu-tion of SLRs to its origins. Polarization resolved extinction spectra of arrays formed by a few nanoparticles were measured, and found to be in very goo