This paper describes the optical system and the main elements of a pro
totype of a near-field scanning optical microscope, based on the use o
f the tunneling effect of light from a sample into a point lightguide
using total internal reflection. A personal computer is used to contro
l the displacement of an insulating point by means of a three-coordina
te piezoceramic manipulator and to record the image. A He-Ne laser is
used as the light source. Topographic images of the surface microstruc
ture of transparent samples are obtained with a resolution of 0.1 lamb
da in the plane of the sample and 0.002 lambda in height. (C) 1997 The
Optical Society of America. [S1070-9762(97)01212-8].