Near-field optical microscope based on local perturbation of a diffraction spot.

Using a vibrating opaque metallic tip, which periodically and locally modif ies the electromagnetic f ield distribution of a diffraction spot focused onto a sample surface through a microscope objective lens, we have observed optical resolution better than the diffraction limit both with topographical features and with purely optical ones. This procedure simultaneously generates a ref lection-mode near-field optical signal and a tapping-mode atomic force microscope signal and can therefore map independently the topography and the optical properties of a specimen.  1995 Optical Society of America