Abstract

At the University of Melbourne we are developing a program of research into near-field scanning optical microscopy (SNOM). The principle aim of this program is to characterize the optical properties of the near-field probe commonly used in such microscopy. To do this we are using near-field probes to perform detailed measurements of well characterized diffracted optical fields. Such structures include near-field diffraction patterns of straight edges and high N. A. lens focal distributions. Many of the fields have not previously been directly observed and, in some cases, are of theoretical and/or technological interest. In the first steps toward achieving our aim, intensity maps in planes parallel, and perpendicular to, the axis of a single-mode optical fiber have been recorded. Previous investigation of these fields has only been possible in the near-field using an analogue microwave experiment. The maps were recorded by scanning a 100-nm diameter aperture of the type used in SNOM through the fiber output, and they contain both near-field and far-field information. The techniques yielded data with a dynamic range of better than 10³. The results are compared with theoretical predictions.

© 1991 Optical Society of America