Testing acylindrical microlenses at grazing incidence

An interferometer is described which allows the fast test of acylindrical m icrolenses at grazing incidence. The interferometer uses two diffractive op tical elements as beam splitters and beam shapers. For the test of cylinder lenses at grazing incidence a conical test wavefront is needed, which is g enerated by diffraction at a phase structure. One main feature is that the sensitivity only depends on the pitch of the diffractive elements. The inte rferometer, the fringe evaluation method, and the method to eliminate aberr ations an described in detail and measurement results are presented.