Abstract: Interferometry with a holographic optical element for measuring the shape of large aspherical surfaces is reported. The interference fringe pattern between a parallel reference beam and a reconstructed wavefront from a master zone plate which has a very precise pattern drawn by an electron beam drawing machine is recorded on a hologram plate with an off-axis optical arrangement. The hologram plate used as the standard element is reconstructed by the conjugate beam in a modified Twyman-Green interferometer. Insufficient parallelism of commercial hologram plates and the difference in reflection ratio between a sample and the reference mirror can be compensated by this method. Not only rotationally symmetric lenses but also nonrotationally symmetric samples are available. It is also easy to make replicas. Some experimental results are also presented.!5
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