Periodically operating optical path length modulator for periodic change of optical path length of a light beam e.g. in optical interferometry

摘要

The modulator includes light beam (1) conducted by 4-mirror/reflector path length modulator having rotational axis oriented 90 degrees to the angle of incidence of incident light beam. The 4-mirror/reflectors are arranged in pairs on two support or carrier plates, spaced diagonally in comparison with disposed mirror surfaces parallel to each other and which rotate around a common axis (6). the light beam is reflected at a retroreflector (4). A planar disk (20) or liquid filled prism bulb (21) with plane-parallel windows is additionally arranged before the retroreflector.