CPC G01M 11/005 (2013.01) [G01B 9/02011 (2013.01); G01B 9/02039 (2013.01); G01B 11/2441 (2013.01)] | 24 Claims |
1. A method for characterizing a surface shape of an optical element, the method comprising:
a) carrying out at least one first interferogram measurement, said first interferogram measurement being carried out on the optical element in an interferometric test arrangement by superposing a reference wave, which has not been reflected at the optical element, on a test wave, which has been generated by diffraction of electromagnetic radiation at a diffractive element and reflected at the optical element;
b) carrying out second interferogram measurements, said second interferogram measurements being carried out on a calibration mirror for determining calibration corrections, wherein the second interferogram measurements comprise a first-polarization-state measurement and a second-polarization-state measurement, wherein the first-polarization state differs from the second-polarization state; and
c) determining a figure of the optical element based on both the first interferogram measurement carried out on the optical element and on the determined calibration corrections.
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