Tailoring the transmittance of integrated optical waveguides with short metallic nanoparticle chains

We study the ability of noble metal nanoparticle chains supporting localized surface plasmons to tailor the transmittance of channel waveguides on which they are deposited. The optical interaction between a microwaveguide (MWG) and various arrangements of nanoparticles is first analyzed by means numerical calculations based on the Green's tensor formalism. For specific geometries of the particle chains, the transmission spectra of the composite device (MWG and nanoparticles) exhibits strong modulations in the optical range with the appearance of a neat band gap. The results of an experiment inspired by this theoretical study are also discussed. The photon scanning tunneling microscope images recorded over a MWG decorated with a short chain of gold nanoparticles for two different incident frequencies are found to be in qualitative agreement with the theoretical proposal.