CONICET | Buscador de Institutos y Recursos Humanos

Nanometric optical resolution in atomic corrugated samples is obtained using plasmonic probes based on nanoparticle-decorated silica spheres, which act as enhancers of the optical near field [figure 1]. We show that the optical resolution is dependent on the wavelength and polarization of the exciting field. We also demonstrate that the probes are sensitive to the dielectric constant in heterogeneous materials, showing clear optical contrast even in the absence of the contrast provided by tunneling microscopy.  Approach curves reveal that the enhancement is due to cavity modes between the plasmonic probe and the sample, supplying high resolution optical images in an apertureless Near Field Scanning Optical Microscope.These probes can achieve images with subnanometric optical resolution when atomic corrugated samples are sensed.