G B Smith and A A Earp 2010 Nanotechnology 21 015203 doi:10.1088/0957-4484/21/1/015203
G B Smith and A A Earp
Show affiliationsAnomalous strong resonances in silver and gold nanoporous thin films which conduct are found to arise from isolated metal nano-islands separated from the surrounding percolating metal network by a thin loop of insulator. This observed resonant optical response is modelled. The observed peak position is in agreement with the observed average dimensions of the silver core and insulator shell. As the insulating ring thickness shrinks, the resonance moves to longer wavelengths and strengthens. This structure is the Babinet's principle counterpart of dielectric core–metal shell nanoparticles embedded in dielectric. Like for the latter, tuning of resonant absorption is possible, but here the matrix reflects rather than transmits, and tuning to longer wavelengths is more practical. A new class of metal mirror occurring as a single thin layer is identified using the same resonances in dense metal mirrors. Narrow band deep localized dips in reflectance result.
73.22.Lp Collective excitations
78.68.+m Optical properties of surfaces
78.67.Bf Nanocrystals and nanoparticles
78.66.Bz Metals and metallic alloys
Condensed matter: electrical, magnetic and optical
Surfaces, interfaces and thin films
Issue 1 (8 January 2010)
Received 30 July 2009, in final form 23 October 2009
Published 30 November 2009
G B Smith and A A Earp 2010 Nanotechnology 21 015203
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