Multibeam interferometers are widely used in optical spectroscopy and quantum electronics. However, in examining the properties, their mirrors are assumed to be infinite, as a rule. In this work a theory of multibeam interferometers is developed with consideration of the phenomenon of diffraction, where a modal approach is used. An expression is found for the mode transmission coefficient. The developed theory makes it possible to evaluate the effect of finite dimensions of the mirrors of the interferometer and the illuminating beam on the effectiveness of transformation of the latter.
Department of General Physics and Wave Processes, Faculty of Physics, Moscow State University, Leninskie Gory, Moscow, 119992, Russia Department of Scientific Information, Moscow State University, Leninskie Gory, Moscow, 119992, Russia