Abstract

It has long been recognized that aberrations of the optical system comprised of the interferometer cavity and the viewing system can result in distortion of fringes^1-5. However, what is less understood is that the aberrations of the optical system, especially the viewing system, can influence the optical path difference (OPD) of interference fringes between the reference wavefront and the test wavefront due to the fact that rays from the test surface may not trace the exact same optical path as those from the reference surface. The propagation error that is produced by the optical system and the aberrated surface or optical system under test is basically pupil shear of the viewing system and is referred to here as the shearing error.

© 1992 Optical Society of America