Error analysis of an interferometric line-based form measuring system

The precise form measurement of nonspherical optical surfaces, e.g. aspheres, is still challenging. A new form measurement system enables fast measurements of arbitrary rotational symmetric specimens. The system is a preliminary result of a joint project funded by the Deutsche Forschungsgemeinschaft (DFG). It combines a fast line scanning interferometer with subaperture stitching and was presented at the most recent annual DGaO meetings [1, 2]. The system is highly flexible and can be adapted to many specimen geometries. A realistic model of the system has been developed which allows us to perform virtual experiments and especially to simulate the influences of main errors on different specimens. With this model the noise of the fringes, the misalignment of the specimen, or the run-out of the movement axes can be quantified. The simulation model will be compared with real measurements to verify the model. The simulations will be presented and the main error influences of the system will be discussed. [1] S. Laubach et al. DGaO Proceedings A20 (2014) [2] S. Laubach et al. DGaO Proceedings P5 (2015)