Phase-measuring laser feedback interferometry: applications to microscopy

This brief proceedings paper presents an introduction to our adaptation of the principles of phase shifting interferometry to a laser feedback interferometer. The application of these methods allows a direct measurement of both the optical path length and the fringe modulation. Examination of the spatial variation of both of these quantities over an object's surface provides a quantitative map of the geometry of a sample's surface. We demonstrate that discrete phase shifting methods can be used to accurately measure optical path length changes and fringe modulation.