C. Durkan et Iv. Shvets, STUDY OF SHEAR FORCE AS A DISTANCE REGULATION MECHANISM FOR SCANNING NEAR-FIELD OPTICAL MICROSCOPY, Journal of applied physics, 79(3), 1996, pp. 1219-1223
Results of the investigation into the suitability of the shear-force d
istance regulation mechanism for scanning near-field optical microscop
y (SNOM) are presented. It is shown that there is a range of relative
sizes of surface features to tip size that gives rise to malfunctions
of the shear-force distance regulation mechanism. If the size of the t
ip is comparable to the size of any depressions on the sample, the cor
responding shear-force image may show contrast reversal. It is also sh
own that the resolution obtained when imaging a surface with the shear
-force scanning microscope may differ for the two perpendicular latera
l directions. The resolution along the oscillation axis is usually low
er than the one perpendicular to it. This has implications for SNOM im
ages. Therefore, the interpretation of shear force, and hence SNOM ima
ges, may become complex when imaging any sample with significant surfa
ce roughness. (C) 1996 American Institute of Physics.