Superresolution imaging of fluorescent nanospheres by using high-index microspheres embedded in slabs with illumination provided by plasmonic array

International audienceIt is shown that the resolution of virtual images of dye-doped dielectric nanospheres obtained through dielectric microspheres can be increased beyond the classical diffraction limit by decreasing the period of nanoplasmonic array used for localized plasmonic structured illumination of these objects. In contrast to far-field superlens design, the superresolution is obtained without using metallic layers and gratings after superlens. In addition, it is shown that the postimaging processing, which represents an intrinsic part of SIM, is not required for achieving the super-resolved images. This observation is interpreted based on a concept that the radiation of objects placed at the surface of nanoplasmonic arrays with sufficiently short periods is initially provided into folded dispersions of nanoplamonic array, so that the diffraction orders responsible for super-resolution are more efficiently coupled to dielectric microspherical antenna compared to that for the propagating modes within the cutoff frequency