SCATTERPLATE INTERFEROMETRY

Abstract

This study provides a description of scatterplate interferometry from both a theoretical and experimental viewpoint. Although this interferometer is a relatively simple and very effective device for use in the optical shop, very little beyond a qualitative description has been previously presented. Through the use of Fourier optics and stochastic processes techniques, a more formalized theory of scatterplate interferometry is shown particularly in how the flip or inversion symmetry of the scatterplate itself affects the flip symmetry. Also described are the effects on the fringe quality produced by non laser sources as well as aberrations in the interferometer optics. Experimental verification of these aspects is shown to be in good agreement with the theory. Of interest to the shop user of this interferometer is the material presented on scatterplate fabrication. Techniques for making the conventional, "double-exposure" or "180°-type" scatterplate, are very simple to those with access to a holography lab. Additional refinements including null testing with the scatterplate and an infrared scatterplate interferometer are also described.