High accuracy micro scale measurements using a conventional far field microscope

The ability to utilize a conventional far field microscope to perform highly accurate measurements at the nano scale is presented. The free electrons on a metallic surface can be excited by evanescent waves producing surface plasmons. The surface plasmons are electromagnetic waves that by decaying can generate photons. These photons produce propagating waves that feed energy to an oscillating cavity. From this effect a Fabry-Perot like interferometer is generated. Essentially by using the transformation of evanescent waves into propagating waves via the plasmon generation it is possible to perform high accuracy contouring of any metal surface as well as the determination of its contact stresses. A laser beam illuminates a glass-air-metal interface and through proper setup it can produce double evanescent illumination. This illumination produces interference fringes that contain surface depth information as well as in-plane strain information. Some applications are discussed briefly to demonstrate the technique’s unique capabilities.