Moire Fringe Measuring System for Far Infrared Interferometric Spectrometer

摘要

A moiré fringe measuring system is used to monitor the path difference in a far infrared interferometer. The system uses a grating of 10U spacing and gives a passage of one fringe for each 5U of motion by means of an optical setup originally described by Palmer. A modification of Palmer's system, which utilizes the broad fringes produced with the relatively coarse grating, is described.