Phase shifting diffractive interferometer with double pinhole and large aperture and test method

摘要

The present invention relates to a double-pinhole large aperture phase-shifting diffraction interferometer and a test method; the diffraction interferometer comprises: a reference light passage, a test light passage, and a pinhole substrate; wherein the pinhole substrate comprises a test pinhole and a reference pinhole; wherein the diffraction wavefront emitted by the test pinhole is reflected by the optical component to be tested in the vicinity of the pinhole substrate and converges in the vicinity of the reference pinhole, and the respective diffraction wavefront comprises information regarding the surface finish of the optical component to be tested and by the Pinhole substrate is reflected and interferes with the reference pinhole emitted diffraction wavefront to form interference fringes. The double pinhole, large aperture phase shifting diffractive interferometer of the present invention utilizes a double pinhole substrate and an illumination mode with two converging light paths to avoid interference between the two optical paths which would cause a change in interferogram status during phase shift. By using a detection system for optically detecting a small field interferogram, the present invention avoids interfering with the test light passage and achieves a large numerical aperture test under phase shift conditions.