Optical Testing Using Synthetic Holograms

Abstract

A modification of the procedure of Birch and Green for computer generation of holograms is presented. The modified procedure is capable of generating holograms of more than 500 fringes with relative ease, thus making the testing of steep aspherics feasible without compensating optics. The ability of computer-generated holograms to evaluate aspherics was demonstrated by comparing the aspherical wavefront of a plano-convex lens at both on-axis and off-axis positions with the reconstructed wavefront of the hologram. The comparison indicated that the wave-aberration of the lens could be compensated by the hologram with an accuracy of ± λ/20.