Holography as a tool in the testing of large aperture optics

This paper describes applications of holography to the testing of large optical surfaces. In one application a hologram of the wavefront from the mirror is made with a pulsed laser and then used in place of the mirror for Foucault knife-edge testing. This allows the mirror to be tested in its working environment. In the second application the hologram is made in the same manner, but is used in a common path interferometer where the reconstructed point image of the mirror is interfered against a point source to show the difference between the mirror surface and a reference sphere.