Extremely narrow plasmon resonances based on diffraction coupling of localized plasmons in arrays of metallic nanoparticles.

We experimentally demonstrate extremely narrow plasmon resonances with half-width of just several nanometers in regular arrays of metallic nanoparticles. These resonances are observed at Rayleigh's cutoff wavelengths for Wood anomalies and based on diffraction coupling of localized plasmons. We show experimentally that reflection from an array of nanoparticles can be completely suppressed at certain wavelengths. As a result, our metal nanostructures exhibit pi-jump for the phase of the reflected light.