Zero fringe visibility in the classical localization plane of a two-beam interferometer

In 1987 we published "Fringe localization depth" Appl. Opt. 26, 5125 (1987)], where, with first principles, we generalized the van Cittert-Zernike theorem for two-beam amplitude-division interferometers illuminated by extended sources. In this generalization the complex degree of coherence between the interfering beams is equivalent to the Fraunhofer diffraction pattern of an aberrated optical system. In 1989 Hariharan and Steel Appl. Opt. 28, 29 (1989)] commented on this paper and pointed out that the fringe visibility can be zero in the localization plane determined by the conventional pair-of-rays method. Now, we numerically and experimentally show a situation where the equivalent aberrations are such that this finding is verified and that the localization region splits in two, one ahead of and the other behind the classical localization plane.