Interferometry from 1950 to the present

Abstract
This review paper deals with the history, the important aspects, and the development of far-infrared Fourier transform spectroscopy and Fabry-Perot interferometry from 1950 to the present. Most of the fundamentals of Fourier spectroscopy were worked out in the period from 1951–1961 after the realization of the multiplex advantage. The following period from 1962 to the present brought new instrumental innovations and refinements and the stage of general use. Fabry-Perot interferometry became possible in the far infrared since metal mesh was found to be the ideal reflector for the interferometer. This kind of interferometry is now mainly and increasingly used in connection with far-infrared laser research.