On the spatial resolution of uncoated optical-fiber probes in internal reflection near-field scanning optical microscopy

We present conclusive experimental quantitative evidence of the resolution limit of uncoated optical fiber probes in the internal reflection mode. Additionally, we present a new technique for unambiguously determining the resolution of a near-field scanning optical microscope without topographical influences. A sample with nearly no topography but with a large dielectric step junction was created by evaporating a thin chromium layer on a silicon wafer and subsequently cleaving the wafer. The cleaved edge is then scanned over the step junction, allowing a quantitative determination of the lateral resolution without topographical influences.