Scattered light interference from a single metal nanoparticle and its mirror image.

The spatial distribution of surface plasmon scattering from a single nanoparticle changes dramatically near a metal surface as a result of interference from the direct scattered light and indirect scattered light from the mirror reflection. The unique interference patterns have been reproduced by simulations based on Huygens-Fresnel wave propagation theory. The large spectral width of the surface plasmon scattering enables a vertical distance measurement with 10 nm resolution through this nonintrusive far field interferometry.