Spatial resolution and optical near-field enhancement of scanning probes for apertureless near-field scanning optical microscopy depend strongly on the properties and geometry of the scanning probe. A new approach for very sharp probes with well-defined geometry based on gold nanocones is described and demonstrated on planar substrates. The fabrication involves a combination of thin-film deposition, electron beam lithography, and reactive ion etching or ion-milling, respectively. Well-defined gold nanocones with a tip radius of 10 nm and less on silica and bismuth pillars are obtained in a self-aligned process. The numerical simulations of the field distribution near the tip apex and the experimental verification via a photoluminescence intensity measurement are given, showing that these novel probes are suitable for performing optical measurements. (C) 2010 American Vacuum Society. [DOI:10.1116/1.3518461]