Near field microscopy
In conventional optics, the resolving power of an optical device is limited by the diffraction limit. However, metallic and dielectric nanostructures are able to localize the electromagnetic field of light into a length scales much smaller than the wavelength, thus allowing for optical imaging beyond the diffraction limit. The strongly localized non-radiative electromagnetic field is called near-field, as it extends only by little outside the nanostructures. Together with the developments in scanning probe microscopy techniques, electromagnetic near-fields of nanostructures are exploited to obtain nanoscale resolution of objects, forming a set of techniques known as near-field microscopies.
The standard way to perform an apertureless near-field microscopy is to use a sharp scanning tip to scatter the near-field of a nanostructure into the far-field, thus accessing the information on the size, shape, the dielectric environment of the nanostructure, etc. Alternatively, one could use of a scanning probe with an aperture, simultaneously illuminating the structure and collecting the scattered light.
We study theoretically the optical response of metallic and dielectric nanostructures, optimizing them to perform near-field microscopy, investigate the complete systems of nanostructures and their coupling to scattering probes.