The absolute testing of optical flats through the use of the rotation-shift method is discussed. Absolute deviations of three flats are determined by the evaluation of at least four interference patterns of pairs of these flats. In the rotation-shift method the absolute deviations are calculated at the points of a square grid. The propagation of error in measurements of the interference patterns to the magnitude of the error of the overall result is calculated with respect to special combinations of pairs of the flats. Proposals are made to minimize the error propagation. The mean-square value of the error-propagation factors is in the range of 0.75. Square grids of up to 151 points × 151 points are used.
© 1994 Optical Society of America
Jürgen Grzanna, "Absolute testing of optical flats at points on a square grid: error propagation," Appl. Opt. 33, 6654-6661 (1994)