Principle of Apertureless Scanning Near-Field Optical Microscopy: On the Way to the Optical Metrology of Nanostructures

Abstract : Apertureless Scanning Near-Field Optical Microscopy (A-SNOM) is a powerful tool for the observation and engineering of nanostructures in near-field optics (NFO). Nevertheless, the interpretation of the experimental recorded signals raises several difficulties due to the strong dependance of the image formation process on the shape and the optical index of the nanostructure, the properties of the probe and also on the illumination and detection conditions of the experimental configuration used. In order to perform an optical measurement, an accurate model and an inversion procedure are necessary. This last approach may offer a wide variety of applications to the SNOM (e.g. the metrology of nanostructures, the optical, thermal properties, or of optical forces...) In this contribution, we focus our attention on an A-SNOM model for metrological applications in near-field optics.