Fourier spectrometer with dual beam interferometer for space vehicle cryostat - contains deflection mirrors between beam divider and retroreflectors mounted on pendulum arms

摘要

The optical or Fourier spectrometer contains a two-beam interferometer in which a measurement beam is divided (1) into two partial beams (S1,S2) which are direted to two retroreflectors (3,12) on two arms of a rotatably mounted pendulum (20) and at equal distances from the pendulum axis (7). The centre of gravity of the pendulum, including the retroreflectors, lies on the pendulum axis. The partial beams pass to and from the retroreflectors via deflection mirrors (34,35). The planes defined by the path sections between the divider and the deflection mirrors and between the deflection mirrors and the retroreflectors are essentially mutually perpendicular. USE/ADVANTAGE - Makes use of more than half of retroreflector's cross sections, to be insensitive to mirror deadjustment and to contain short optical paths.