Plasmonic Features in the Absorption Spectrum of a Monodisperse Ensemble of Gold Nanoislands on Sapphire

Plasmonic features in the absorption spectrum of a monodisperse ensemble of gold nanoislands on a sapphire substrate are considered. An explanation of the long-wavelength and UV bands in the absorption spectrum of the sample is proposed. The long-wavelength feature is interpreted as a consequence of surface plasmon polariton excitation under coherent scattering from a regular lattice of gold particles on sapphire, and the short-wavelength feature is considered to be a plasmon resonance, localized on individual gold nanoparticles.