Refractively scanned interferometers

Figure 5.25. Refractively scanned interferometer designed by Doyle. (Originally reproduced by permission of the Analect Instruments Division of Laser Precision Corporation.)...

One potential disadvantage of refractively scanned interferometers is the effect of dispersion on the wavenumber accuracy. However, the variation of n with wave-number is known and this effect can be compensated accurately by the appropriate software. This disadvantage is more than offset by the fact that the stationary cube corners in each arm of the interferometer give it a remarkable immunity from the effects of tilt and shear. As a result, this interferometer is often used for process monitoring by FT-IR spectrometry. This interferometer has been installed as the key component of process monitors in well over 100 plants. 

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