Grazing incidence interferometry with the help of diffractive masters

The test of rod-like technical objects can be carried out in grazing incident using diffractive optical elements as beam splitters and at the same time as generators for master wave fronts. The occurring interference patterns can be evaluated with the help of the well known phase shifting technique. Wave aberrations caused by the adjustment state of the test sample can be removed from the data set via least squares fitting a functional representing the wave aberrations due to misalignments.