Abstract

A lateral resolution in a conventional optical microscope is limited by the diffraction effects of light. We wanted to develop a superresolved microscope that could operate at ambient conditions because such a microscope would be useful in many fields. This paper describes a scanning Wiener fringe optical microscope (SWM). When a plane wave incidents on a sample, a Wiener fringe, which is a kind of standing wave, results in the region of the sample surface where the reflected wave overlaps with the incident beam. A light probe, which is made by sharpening an end of single-mode fiber, can detect the optical field of the Wiener fringe. The light transmitted through the fiber to a photomultiplier tube is converted to an electrical signal, which is fed to a lockin amplifier for synchronous detection. The detected signal is used to control a tip-sample spacing at the constant phase of the Wiener fringe, so that a topographic image of the sample can be obtained by accumulating a feedback signal to a computer while scanning the fiber tip over the sample.

© 1991 Optical Society of America