A method and arrangement for the calibration of the wavefront error of a computer-generated hologram for the testing of optical surfaces

摘要

A method for the calibration of the wavefront error of a cgh for the testing of an optical surface, in which by means of the computer-generated hologram for beam shaping of a measuring shaft (31), adapted to the shape of the to be measured on the optical surface (21) of a test piece (2), light of a fizeau - interferometer (1) essentially only in the. + -. 1. order of diffraction deflected and for testing the optical surface (21) back to the reflected from this - fizeau interferometer (1) is supplied, characterized by the following steps:– Insertion of a cgh (3) in the form of a phase grid, the by a deviation from an ideal groove depth, in which no light into straight diffraction orders and almost all of the light in the. + -. 1. diffraction orders, a defined between 2 and 10% set proportion of the intensity of the fizeau - interferometer (1) as a calibration light coming into the 0. Order of diffraction transmitted, as a result of which the in the. + -. 1. diffraction orders deflected component is weakened only to the extent that the measuring operation of the test piece (2) is not negatively influenced,– Adjustment of the computer-generated hologram (3) with respect to the fizeau - interferometer (1) and which are to be measured optical surface (21) along the optical axis of the fizeau - interferometer (1),– Insertion of a planar reference mirror (4) extends perpendicular to the optical axis between the cgh (3) and the optical surface (21),– The transmission of a planar wave (12) of the fizeau - interferometer (1) in the direction of the reference mirror (4), wherein the planar wave (12) by reflection at the reference mirror (4) passes through twice the cgh,– Detection of deviations of the at the reference mirror (4) is reflected back into itself planar wave (12) of the 0. In the order of diffraction - fizeau interferometer (1) and storing the deviations in the form of a calibration data of the test device with planar waves illumination of the computer-generated hologram (3).