Shearing-interferometry method of investigating the volume distribution of optical inhomogeneities in spatially extended phase objects

An interferometry method has been proposed and tested for investigating the inhomogeneity of transparent three-dimensional objects in cross sections normal to the direction of a probe beam. Interferograms that contain the indicated information are obtained by forming a probing light beam with low spatial coherence and by recording shearing interferograms for which two images of the object of interest are brought into coincidence so that pairs of coherent points in them spatially coincide. The probing light beam is formed by means of an interference synthesizer that carries out amplitude division of the source beam into two identical beams and brings them into coincidence with a relative spatial shift. Then, after the probe beam passes through the object of interest in the interferometer unit, the images are brought into coincidence. Experimental checking is carried out by using phase screens.