Analysis of interferograms of a lens using a knife edge interferometer

In previous works Korneev, et al. and Cornejo, et. al. Shown the feasibility to produce an interference pattern, by setting near by the focal point of a lens a razor knife edge. The interference phenomena is produced between the wavefront coming from the lens, and the wavefront produced by the knife edge. In this work, such technique is applied for testing a lens. Since partial interferograms are observed, due to the obstruction of the knife edge to the wavefront coming from the lens; by rotation of the knife edge in several directions, interferograms with different information can be registered by means of a CCD connected to a PC. Experimental measurements are given after several interferograms with different number of fringes were analyzed.