Si. Bozhevolnyi, TOPOGRAPHICAL ARTIFACTS AND OPTICAL RESOLUTION IN NEAR-FIELD OPTICAL MICROSCOPY, Journal of the Optical Society of America. B, Optical physics, 14(9), 1997, pp. 2254-2259
Starting from general principles of near-field optical microscopy, I d
emonstrate that an optical image obtained with any near-field microsco
pe operating in a constant (probe-surface) distance mode contains pure
topographical artifacts, topographically induced features, and pure o
ptical contrast. Scanning a sharp topographical step at an otherwise h
omogeneous sample surface is shown to provide a sensitivity window tha
t determines the scale on which the near-field optical image would rep
resent mostly pure optical contrast. I suggest that the sensitivity wi
ndow can be regarded as the upper limit of optical resolution of a nea
r-field microscope. (C) 1997 Optical Society of America.