An amplitude-division two-beam interferometer illuminated by a quasi-monochromatic, spatially incoherent, and periodic source yields multiple localization planes of interference fringes. If a thick transmission sample with a few localized phase disturbances in various layers is placed in the interferometer, the disturbances in a layer can be detected, making its images through the two arms coincide with a chosen localization plane. Different layers can be analyzed by means of shifting the localization plane by a variation of the source period without any other changes in the device. Here we illustrate this method by applying it to a shearing interferometer, a classical Wollaston prism placed between crossed polarizers. Experimental images of different observation planes are obtained, and they are in good agreement with the theoretical expectations.
© 2001 Optical Society of America
Juan M. Simon, Silvia A. Comastri, and Rodolfo M. Echarri, "Shifting of Localization Planes in Optical Testing: Application to a Shearing Interferometer," Appl. Opt. 40, 4999-5010 (2001)