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
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