Plasmon Behavior Analogous to Electron Dynamics

Scientists at Rice University in Houston, Trinity University in San Antonio and Chalmers University of Technology in Göteborg, Sweden, have discovered that plasmons in a metallic nanoparticle interact with surface plasmons in a nearby metallic film in a manner analogous to the way electrons and a continuum of electron states do under the classical impurity model. The researchers suggest that the findings may enable the development of nanoscale structures to convert light into broadband electrical signals with the ability to carry orders of magnitude more data than interconnects do today.

The investigators sought to understand how the thickness of the adjacent film affected the interaction of the plasmons — electron oscillations that carry the energy of a photon — in the nanoparticle and film. Measurements of the extinction spectra of 50- and 100-nm-diameter gold particles deposited atop a 3.5-nm-thick polymer layer on 4-, 8-, 12- and 16-nm-thick gold films indicated that the energy level of a virtual plasmon resonance in the film was directly correlated to the thickness of the film.

They reported the work in the Sept. 14 online edition of Nano Letters.