Fabrication of a fiber probe with a nanometric protrusion for near-field optical microscopy by a novel technique of three-dimensional nanophotolithography

A new technique based on photolithography has been developed to fabricate a fiber probe with a nanometric protruding tip for near field optical microscopy. As a first step, an optical fiber is sharpened by chemical etching and coated with metallic film. Next, it is coated with photoresist and its apex region is selectively exposed to an evanescent wave. Finally, the metallic film at the apex region is etched away. The foot diameter of the protrusion fabricated by this method is about 30 nm.