Issues in Step-Scan FT-IR Spectrometry
A rapid-scan spectrometer using a TGS
detector typically operates with a mirror velocity of
0.15 cm/s producing a modulation frequency of 5 kHz at
the reference laser wavelength, 1.25 kHz at 4000 cm-1
and 125 Hz at 400 cm-1. The corresponding
separation between adjacent spectral elements is 1.3 Hz.
If a cryogenic detector is used, a higher mirror velocity
may be used, producing modulation at the laser wavelength
as high as 100 or 125 kHz, with a separation of 25 to 30
Hz between adjacent spectral elements.