Michelson interferometer with two read-out phases for the double-face strain measurement

A modulation interferometer for the measurement of small strains is proposed that allows for the double-face detection of the vibrations of a specimen. While earlier approaches were based on polarisation-optical schemes or a repetition of the set-lip, the sequential measurement principle proposed can be realized without polarisation-optical components or doubling. But this is partially conterbalanced by the we of additional electromechanical positioning elements.