An arrangement for building a compact Fourier transform interferometer for
optical radiation according to the Michelson principle or a principle
derived therefrom. According to the invention, this arrangement is
characterized in that the optical modulation of the radiation in at least
one of the interferometer arms is produced by the translational
displacement of micromechanical translation mirrors that are optically
accessible on one side or on both sides, with an effective oscillation
amplitude of at least 50 .mu.m and a usable mirror surface area of at
least 1 mm.sup.2. In doing so, the micromechanical mirror components
according to the invention assume the function of known movable mirrors
so that by using an almost massless microcomponent in comparison to
conventional systems, a much smaller size and a mirror modulation
frequency that is several orders of magnitude higher can be achieved. The
arrangement according to the invention is used especially for optical
spectroscopy.