Two types of interferometers

In the previous paragraph, we saw that there are amplitude-splitting interferometers that are characterized by the fact that the unit vectors and are collinear; this means that the interfering rays correspond to two emissions from the interferometer produced by the same incident ray.

The other variety of interferometers are wavefront-splitting interferometers. There are inconvenient because they cannot be used with a wide source, since the fringes rapidly become confused with the dimension of the source. For both kinds of interferometers, the interferences are not localized, that is to say they are not observable in all of the field of view, when the source is non extended. On the other hand, in the case of a wide source with an amplitude-splitting interferometer the interferences are localized at the intersections of pairs of emerging rays corresponding to the same incident ray.

The table beneath summarizes the previous sections.

In the module “Interference: interferometers” the reader may find different examples and analyses of such devices.