Testing of cylindrical lenses by grazing incidence interferometry

In the production process of cylindrical lenses it is important to control the relative orientations of the two cylinder axes and of the plane side su rfaces in order to alleviate assembly of the optical system containing the cylinder lens. A grazing incidence interferometer can be used to test all f unctional surfaces simultaneously and without contact. Here diffractive opt ical elements serve as beam splitters and as references for the surfaces un der test. Using tailored fringe processing techniques, the geometrical erro rs of the cylindrical lens can be determined. These comprise relative shift and rotation between each pair of surfaces and individual surface figure e rrors.