Interferometric testing of curved, spherical and aspherical, reflective surfaces using an interferometer and a diffractive optical element, with the latter generating a reference wave and a measurement wave

摘要

System for interferometric testing of the surface (1) of a test object (2) uses an interferometer and an optical element (3) with a diffractive structure (4) on its surface. Said structure generates a conjugated reference wave (7) by diffraction of the incident light wave (6). At the same time the structure serves as a null-optics transmission device with a measurement wave (8) generated, transmitted to the test object and then back scattered from the object so that it overlaps and interferes with the reference wave.