Shearing interferometry system for measurement of a wave front for use in measuring an optical imaging system in order to quantify its quality, said system having filters to suppress unwanted higher diffraction orders

摘要

Device for measuring an optical imaging system by wave front measurement using shearing interferometry comprises: an illumination component on the object side prior to the imaging system (1); a diffraction grating (3) arranged in front of the image plane; a filter mask (4) in the image plane and a detector unit (5) arranged after the detector. The illumination component has a coherence mask (2) with a multiple opening mask structure that is used to suppress undesirable diffraction orders. Alternately or additionally the filter mask in the image plane can be moved.