The effects of temporal and longitudinal spatial coherence in a disbalanced-arm interferometer

During the interference of optical fields possessing broad frequency and angular spectra in an oscillating-mirror Michelson interferometer, the presence of a film introducing an additional optical path increment in one of the arms leads to a mutual shift (recession) of the signals of temporal and longitudinal spatial coherence. This phenomenon leads to breakage of the mutual coherence of the interfering fields. In the presence of two light sources, this effect can be used for the independent determination of the thickness and refractive index of the film.