Eigenschwingungen und Mehrstrahlinterferenzen in Interferometern mit Phasenstörungen

Abstract

Experiments with an interferometer for cm-waves show that the normal oscillation modes of open resonators are modified in a characteristic manner, if a small phase-object or a corresponding mirror step is inserted. We found a close analogy between oscillation modes in such an interferometer and longitudinal-section waves in waveguide tubes partially filled up with dielectric substances. This analogy permits quantitative statements which are well confirmed by experiment.For interferograms with displaced interference fringes -well known from conventional interferometry -it is shown that they must be considered t o arise actually from superposition of the fields of several simultaneously excited low-order modes. Thus it was possible to obtain information about the basic effects in the region of the resolution limit for multiple-beam interferometry.