Near-field optical fiber probes and the applications I

Abstract

A double-tapered type of fiber probe with a typical aperture diameter of 100nm and the GeO2-doped silica core has been widely used for near-field optical microscopy in infrared and visible wavelength regions. However, it is difficult to employ such commercial probes for near-ultraviolet applications because the GeO2-doped silica fiber probe has the strong guiding loss based on the Rayleigh scattering. Furthermore, the GeO2-doped core, under the excitation of a visible light, generates photoluminescence and scattered lights which seriously decreases the ratio of near-field signal to background noise in some near-field applications such as fluorescence imaging and Raman scattering spectroscopy. This chapter describes various types of probe, fabrication methods, and imaging applications.