title: Evaluation of the limits of resonance tunability in metallic nanoshells with a spectral averaging method.
abstract: Spectral selectivity based on tuning the surface plasmon resonance in metallic nanoshells by variation of the relative shell thickness is shown to be limited by the interplay between scattering and absorption. To achieve resonance energies in the near infrared and infrared, relatively large cores are needed, which lead to strong and broad scattering bands and multipolar contributions in the visible. The scattering contribution to extinction is described with a new parameter Sdelta, which is defined for a wavelength range of interest A. This parameter can help in designing materials for specific applications where scattering is either hindering, as in near-infrared absorbers for visually clear windows, or actually desired, such as in particle-array-based sensors.
authors.affiliation: Department of Applied Physics, University of Technology, Sydney, PO, Box 123 Broadway, 2007 New South Wales, Australia. stefan.schelm@gmail.com
authors.forename: Stefan
authors.initials: S
authors.lastname: Schelm
authors.forename: Geoff B
authors.initials: GB
authors.lastname: Smith