White-light interference microscopy: a way to obtain high lateral resolution over an extended range of heights

Abstract

A problem with conventional techniques of interference microscopy, when profiling surfaces with an extended range of heights, is that only points on a single plane are in sharp focus. Other points, which are higher or lower, may be out of focus, with a consequent loss of lateral resolution. We show that white-light interference microscopy, with an achromatic phase-shifter, makes it possible to produce a three-dimensional representation of such surfaces with high lateral resolution over the entire range of heights.