HIGH-ACCURACY DIFFERENTIAL INTERFEROMETRY FOR THE INVESTIGATION OF PHASE OBJECTS

This paper presents an interferometric method for the investigation of phase objects which employs a Mach-Zehnder arrangement with objects b eing located outside. It functions as a differential interferometer wi th the practical advantage that the sensitivity and the carrier fringe system can be chosen arbitrarily and independently. The computerized evaluation is well adapted to the experimental set-up, which helps to achieve high accuracy of the results. For the case of radially symmetr ical objects a numerical method is presented for calculating the refra ctive index distribution from data measured with the above mentioned t ype of differential interferometer The results of a demonstration expe riment are shown and further applications of this differential interfe rometer are discussed.