title: Measuring the range of plasmonic interaction.
abstract: When gold nanoparticles are covered with nanometric layers of transparent polyelectrolytes, the plasmon absorption spectrum A(λ) increases by a factor of approximately three and shifts to the red. These modifications of dissipative experimental observables stop when the cover layer thickness approaches the particle diameter. Spectral modifications of dispersive parameters like the reflection R, however, keep changing with increasing cover layer thickness. The shift of the plasmon resonance caused by two interacting particle layers is studied as a function of the separating distance between the two layers. We discuss these observations in the context of an effective medium theory and conclude that it can only be applied for a layer thickness on the order of the particle diameter.
authors.affiliation: Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Kiel
authors.forename: Madlen
authors.initials: M
authors.lastname: Klötzer
authors.forename: Steffen
authors.initials: S
authors.lastname: Mitzscherling
authors.forename: Matias
authors.initials: M
authors.lastname: Bargheer