<title>Approach for applying holographic interferometry to cases of strong gradients of index of refraction in a fluid using large modifications</title>

Abstract

The use of holographic interferometry to determine large deformations of opaque bodies by compensating modifications when reconstructing has been treated previously in several publications. The present conthbution concerns a similar investigation in the case of a domain with a strong spatial change of the index of refraction as for instance in a gas with a high temperature gradient Firstly, the general theory about the analogy between both fields as well as the image aberration and the fringe modification is outlined. Secondly, a development of the fringe vector in the case of a moderate index gradient is performed, leading to an approach for measuring the integral of the lateral gradient of the index along the curved ray.