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

Abstract

Using a vibrating opaque metallic tip, which periodically and locally modifies the electromagnetic field 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 reflection-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.