Photothermal nonlinear scattering of shell-isolated gold nanoparticles and applications in super-resolution imaging

In this Letter, we report on the investigations of nonlinear scattering of plasmonic nanoparticles by manipulating ambient environments. We create different local thermal hosts for gold nanospheres that are immersed in oil, encapsulated in silica glass and also coated with silica shells. In terms of regulable effective thermal conductivity, silica coatings are found to contribute significantly to scattering saturation. Benefitting from the enhanced thermal stability and the reduced plasmonic coupling provided by the shell-isolated nanoparticles, we achieve super-resolution imaging with a feature size of 52 nm ( λ = 10), and we can readily resolve pairs of nanoparticles with a gap-to-gap distance of 5 nm.