Apertureless scanning near-field second-harmonic microscopy

We propose a new type of apertureless scanning near-field optical microscope based on detection of the second-harmonic signal induced by or generated at a probe tip. We discuss the image formation in this technique and present numerical studies for different experimental circumstances. In two extreme cases this method is shown to be the nonlinear analogue of apertureless scanning near-field optical microscopy based on local nanoscopic fluorescence or scattering. (C) 2000 Published by Elsevier Science B.V. All rights reserved