Influence of alignment error and random noise on interferometry flat sub-aperture stitching

Abstract

In the flat sub-aperture stitching test, the dominant e error comes from two dimensional translation stage that carries the flat under test, which contains tilt and position error i.e., the alignment error. In order to analyze the influence of alignment error on stitching precision, we use Zemax optical software to simulate a system to detect the phase of each sub-aperture of measured flat and add tilt and position errors and random noise to sub-apertures. The simulation model was utilized in this paper to evaluate the mechanical precision of the translation stage in order to meet a required stitching precision of 1/1000λ.

One-dimensional stitching interferometry assisted by a triple-beam interferometer

“…Stitching algorithm can offer good measurement results for freeform mirrors [3] even if the overlapping sub-apertures contain large relative tilt [4]. Stitching interferometers were therefore extensively studied [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and commercialized [5].…”

“…The angle problem is mainly caused by the stage translation and small wedge of mirror body [10]. With the different error sources mentioned above, a stitching algorithm alone cannot provide reliable results [13]. The challenge is even more difficult with strong curvatures mirrors; this will result in obvious stitching errors if a pure software stitching method is used, unless assisted by other instruments, such as a multi-axis positioning device [14] or RADSI system [15] and MSI system [16].…”