Low-coherence interference microscopy using a ferro-electric liquid crystal phase-modulator

Abstract

We describe a computer-controlled low-coherence interference microscope, based on a Linnik interferometer configuration that can rapidly and accurately map the shape of micro-machined surfaces exhibiting steps and discontinuities. The novel feature of the system is a fast, switchable achromatic phase-modulator operating on the geometric phase, using a pair of ferro-electric liquid crystal devices.