Fourier Transform Near Infrared Spectroscopy or FT-NIR Spectroscopy is a technique which is used for chemical identification and analysis. A FT-NIR spectrometer utilize the fact that the functional groups of every molecule generate a characteristic absorption or transmission spectrum that can be used to identify them like a fingerprint. FT-NIR analyzers use interferometers to split the light source. These separate beams are then recombined to create an interferogram which is subjected to a Fourier Transform to produce a spectrum. FT-NIR spectrometer are also able to measure the entire spectrum simultaneously, providing rapid and sensitive data with low noise levels. They also feature internal calibration on every scan.
FT-NIR spectra are not as intense as FT-IR spectra and they often do not require sample preparation, making it faster and enabling it to be used as a form of non-destructive testing.