Frey, H.G.H.G.FreyBolwien, C.C.BolwienBrandenburg, A.A.BrandenburgRos, R.R.RosAnselmetti, D.D.Anselmetti2022-03-032022-03-032006https://publica.fraunhofer.de/handle/publica/21159710.1088/0957-4484/17/13/004Back-illuminated full body glass tips coated with a thin metal layer can be used as local probes for apertureless scanning near-field optical microscopy (SNOM). In order to achieve high spatial resolution, high electric field intensities and low background illumination, the thickness of the metal coating, angular illumination direction, and polarization have to be optimized. Optimal conditions have been calculated and experimentally verified for 10-15 nm thick aluminium and 15-25 nm thick silver layers. Upon imaging single dye molecules, characteristic single and double-peak patterns with peak widths down to 15 nm could be measured, exhibiting an optical resolution which exceeds the classical diffraction limit of Abbe significantly.enoptimized apertureless optical near-field probeback-illuminated full body glass tipoptical resolutionthin metal layerSNOMhigh electric field intensitylow background illuminationangular illumination directionpolarizationsingle dye moleculeclassical diffraction limit10 to 15 nm15 to 25 nm621530journal article