Diffractive interferometer for visualization and measurement of optical heterogeneities

New optical arrangements of the two beam diffractive interferometer with the inverted wave fronts and the combined optical branches based on zone plates are proposed. The special software is designed. The restitution of an interference pattern is performed; the skeleton of fringes is selected; the graphic visualization of optical heterogeneity of a sample is built in the computer-aided processing of interferograms. Proposed DI enable visualizing the optical thickness heterogeneities in the transparent sample, measuring them with accuracy ～0.05λ and can be used for research and quality surveillance of laser crystals and other optical materials.