Designing plasmonic nanoparticle lattices for directional, in-plane lasing

Band structures engineering of periodic optical structures enables the control of light propagation and localization. Although photons trapped inside 2D lattices can be described within the first Brillouin zone in reciprocal space, the wavevectors of scattered photons outside the lattice are limited by the 3D light cone, which depicts the free-photon dispersion in the surroundings. Because plasmonic nanoparticle lattices show unique dual properties of light trapping and strong scattering, this material platform is promising for investigations of radiative losses. This talk describes how light-cone surface lattice resonance (SLRs) from plasmonic nanoparticle lattices allow the observation of radiated electromagnetic fields. We theoretically predicted the angular distributions of the radiated fields, and experimentally probed the light-cone SLR modes by in-plane lasing emission. These results provide a nanolaser design strategy to achieve tunable lasing colors by lattice rotation.