A compact radial shearing interferometer based on the law of refraction

Abstract

A brief review of radial shearing interferometers as well as a logical development of various types of these interferometers is presented. The discussion considers two types of interferometers. One type essentially introduces a radial shear in collimated light while in the other type a radial shear is introduced in converging light. Finally, a compact interferometer is described. This interferometer uses the Snell's law of refraction for obtaining radial shear and consists of two identical prisms which make up a pentaprism. In one of the prisms, a hemispherical depression is made, and this is the basic element that introduces radial shear.