Plasmonics: The benefits of darkness

The dark modes in plasmonic nanostructures leads to devices with sharp resonance's and low losses that promise applications in biochemical sensing and optical communications. These surface plasmons provide a means for light localization below the diffraction limit as well as for enhanced scattering and absorption of photons. The study described the advanced control over the lineshape of plasmons resonance's in metallic nanostructures leading to new applications in biochemical sensing. The coupling of dipolar mode to the dark mode leads to the excitation of the dipolar mode in two possible ways: either directly through the illuminating light field or through excitation of the quadrupolar mode. The results reveal the application of sharp plasmon resonance's in biochemical sensing, where molecular species are identified due to change in local refractive index on binding to the nanostructure. These new illustrated effects created paradigm for the control of light-matter interactions on the nanoscale.