Energy distribution in a scatterplate interferometer

By adding the energy produced in the interferograms and absorbed by the interferometer itself, it must be possible to prove energy conservation in any interferometer. This calculation is relatively simple for two port interferometers such as the Twyman-Green and Mach-Zehnder. If nonabsorbing beam splitters are used, primary and complementary fringe patterns are produced such that when a dark fringe appears in one port a bright fringe appears in the other. The sum of the energy in the two fringe patterns remains a constant. If absorbing beam splitters are used such as thin film aluminum, the two fringe patterns are not necessarily complementary. However, it can be shown that if the energy absorbed by the beam splitter is included in the calculation, the total energy again remains constant. To our knowledge, an analysis showing the distribution of energy in a scatterplate interferometer 2 has not been previously given. The purpose of this paper is to present a conservation of energy analysis for both phase and density scatterplate interferometers and in the