A SIMPLE TECHNIQUE FOR THE MANUFACTURE OF OPTICAL PROBES FOR SCANNING NEAR-FIELD OPTICAL MICROSCOPES

Scanning near-field optical microscopy (SNOM) is a new technique which can resolve objects with sub-wavelength resolution. A convenient technique is to use a sharp fibre tip which detects an evanescent light field, the intensity of which depends exponentially on distance. The sharp tip is made by heating and stretching an optical fibre to draw it out into a fine tip, and subsequently etching the tip in hydrofluoric acid to reduce its radius of curvature to about 100 nm. Features as small as 5 nm in height and less than 100 nm in width have been observed with the fibre mounted in a novel head adapted for use with Digital Instruments Nanoscope II.