Dispersed reference interferometry

Dispersed reference interferometry (DRI) is a potentially useful technique for applications such as absolute displacement, surface topography
and film thickness measurement. A bulk optic implementation of a short coherence dispersed reference interferometer is described with the
chromatic dispersion applied using two matched transmission gratings in one arm. Such an interferometer can provide absolute knowledge of
position by tracking a symmetrical fringe pattern produced by a spectrometer. An operating principle is presented and validation provided
through empirical data from optical apparatus. We present experimental results for the resolution, linearity and repeatability of the
investigated interferometer apparatus.