Design and Construction of a Phase-Stepping Interferometer for the Study of Thin Films

Abstract

A phase-stepping laser interferometer is under construction at Houghton College to study thin metal films. A 50 mW, 634 nm laser in combination with a beam splitter and a series of lenses produce 4 in collimated beams of light. Sets of images are taken by a webcam as a reference mirror moves, producing stepped changes in the interference pattern. The series of pictures are analyzed using a LabVIEW program to create a topographical image of the surface which will be a measure of curvature and will allow for calculation of stresses within the film. The interferometer will be mounted under a deposition chamber, where thin metal films are deposited allowing for in-situ imaging.