Interaction of metallic nanoparticles with dielectric substrates: effect of optical constants

In this paper, we study the local-field enhancement in a system of a metallic nanoparticle placed very near to a dielectric substrate. In such systems, intense electric fields are localized in the gap between the particle and the substrate, creating a ‘hot-spot’ under appropriate excitation conditions. We use finite-element numerical simulations in order to study the field enhancement in this dielectric–metal system. More specifically, we show how the optical properties of the dielectric substrate ( n and k ) affect the plasmonic field enhancement in the nano-gap. We also analyze the degree of field confinement in the gap and discuss it in the context of utilization for surface-enhanced Raman scattering. We finally show the fields generated by real substrates and compare them to metallic ones.

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2012-12-21 10:34:16

Source: http://nanochemistry.blogspot.com/2012/12/interaction-of-metallic-nanoparticles.html