Deducing structural variations of the apex of probes used in near-field optical microscopy through simultaneous measurement of shear force and evanescent intensity

We propose a simple method employing the simultaneous detection of evanescent intensity and shear force to deduce variations in the near-field optical morphology of the apex of the probes used in near-field microscopy. Fabrication of our probes involves sharpening by chemical etching, metal coating, and removal of metal from the apex. We show that through the simultaneous measurement of shear force and evanescent intensity, it is possible to detect variations in the optical morphology of the very apex of the probes during near-field imaging by a scanning near-field optical microscope.