Reproducible fabrication of a fiber probe with a nanometric protrusion for near-field optics

We propose a new type of fiber probe with a nanometric protruding tip emerging from a metal film and describe a novel method, called the selective resin-coating method, for fabricating such probes. It is a reproducible etching process consisting of four steps and can be applied to silica fibers sharpened by selective chemical etching. With this method, we obtained tips with the apex diameter and the foot diameter of the protrusion being less than 10 and 30 nm, respectively, when the gold film was similar to 120 nm thick. (C) 1997 Optical Society of America.