Mach-zehnder interferometer data reduction method for refractively inhomogeneous test objects.

Refractively inhomogeneous, cylindrically symmetric test objects, when placed in a Mach-Zehnder interferometer, cause fringe shifts that cannot be reduced with an inverted Abel integral equation to accurately determine the internal index of refraction distribution. Optical principles have been used to formulate an appropriate method of data reduction that is amenable to reasonably simple numerical procedures. Two analytic examples are presented that demonstrate that under the above conditions the deduced refractivity distribution can be dramatically incorrect, both qualitatively and quantitatively, if an inverted Abel equation is used to reduce the fringe-shift data.