A polarization interferometer has been constructed to study the spectral modulation transfer function of monochromators in the visible region. The instrument consists of a Soleil compensator and interchangeable fixed compensators mounted between polarizers. As the retardation of the compensator is varied the light reaching the analyzer ranges from plane polarized to circularly polarized. In this way a fringe system is generated, permitting the interferogram of a light distribution to be recorded, just as with a conventional two-beam interferometer. The transfer function of a prism monochromator has been studied under varied conditions of slit width and focusing.
James E. Stewart, "Polarization Interferometer for the Determination of Spectral Modulation Transfer Functions of Monochromators," Appl. Opt. 6, 1523-1525 (1967)