Optical characterization of nanosources used in scanning near-field optical microscopy

Abstract

We propose an optical method to characterize tips used in scanning near-field optical microscopy (SNOM). The tip is a nanosource, and its optical emission is studied by an inverted scanning tunneling optical microscopy (also called photon scanning tunneling microscopy) apparatus. Then we can obtain information about the spatial Fourier spectrum of the source. We give the formulas connecting the detected intensity to the properties of the nanosource and to geometric parameters of the apparatus. Our discussion is illustrated by a simple approximation for the nanosource: the Bethe–Bouwkamp model.