Nanoscale chemical mapping through plasmonic tips on AFM-based cantilevers

Noble metal tapered waveguides supporting plasmon-polariton modes are able to localize the optical fields at nanometer level producing a remarkable local electromagnetic field enhancement, which enables the realization of high-sensitivity biochemical sensing devices. Here we report on the design, fabrication and experimental test of a novel photonic-plasmonic device that can be operated as an Atomic Force Microscopy tip and simultaneously for local probing of Raman scattering spectra. This result has made possible by recent approaches in nano-fabrication methods, which allow 3D nanostructuring of metals down to the nanoscale. The device demonstrates label-free detection capabilities on single inorganic nanoparticles and on monolayers of organic compounds in label-free conditions and native environments, allowing a topographic and chemical mapping of the materials with spatial resolution of a few nanometers.