Method for Making Highly-Pointed Glass Tips
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
The resolution achievable in Near Field Optical Scanning Microscopy is determined by the diameter of a submicroscopic light source. Usually, the light source consists of an aperture of about 0.1 micrometer diameter in a thin metal film condensed on a glass body. A suitable method for fabricating such apertures involves the pressing of an appropriately sharpened and metal-covered glass tip against a rigid plate until enough metal at the tip's apex is quenched away to yield an aperture of the desired diameter. The key element is a highly-pointed quartz tip that serves as a punch. The radius of curvature at the apex of the tip must be, typically, of the order of 10 nm. In a first step, rods of about 2 by 2 mm cross-section, 8 mm long, are cut from fused quartz glass and ground to a conical shape at one end.