Fourier Transform Infrared (FT-IR) spectrometry was developed in order to overcome the limitations
encountered with dispersive instruments. The main difficulty was the slow scanning process. A method
for measuring all of the infrared frequencies simultaneously, rather than individually, was needed.
A solution was developed which employed a very simple optical device called an interferometer.
The interferometer produces a unique type of signal which has all of the infrared frequencies “encoded”
into it. The signal can be measured very quickly, usually on the order of one second or so. Thus,
the time element per sample is reduced to a matter of a few seconds rather than several minutes.