Plasmonic surface lattice resonances on arrays of different lattice symmetry

Arrays of metallic particles may exhibit optical collective excitations known as surface lattice resonances (SLRs). These SLRs occur near the diffraction edge of the array and can be sharper than the plasmon resonance associated with the isolated single particle response. We have fabricated and modeled arrays of silver nanoparticles of different geometries. We show that square, hexagonal, and honeycomb arrays show similar SLRs; no one geometry shows a clear advantage over the others in terms of resonance linewidth. We investigate the nature of the coupling between the particles by looking at rectangular arrays. Our results combine experiment and modeling based on a simple coupled-dipole model.