Abstract

We experimentally demonstrate high coupling of light to surface polaritons by means of an optimized scatterer placed at a suitable distance from a polariton-supporting surface. Specifically, we consider poorly-absorbing gold disks acting as nearly-perfect resonant scatterers, which we separate from a gold film by means of a dielectric silica spacer. This configuration leads to resonant coupling between externally incident light and plasmon polaritons in the film with associated cross sections that approach and surpass the fundamental limit ~ λ² imposed by the light wavelength λ. Our method introduces a disruptive, efficient way to solve the in/out-coupling problem in nanophotonics.

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