An alternative approach to interferogram collection and processing for a vintage Bomem DA3 Fourier transform spectrometer


We describe a new way of collecting data from Bomem DA3 Fourier transform spectrometers, bypassing the original computers used by these instruments, which are obsolete and more prone to failure than other parts of the system. We collect the interferogram, helium-neon reference laser, and a trigger marking zero path difference with a modern computer as a function of time at a high data rate, as opposed to as a function of position along the scanning arm of the interferometer. The interferogram is then reconstructed as a function of position (measured in helium-neon fringes) by interpolation. The resulting spectra are at least as good as those obtained from the original data processing methods. This work can be used as a model for reviving other DA3 systems which are in good order with respect to mechanical and electronic components, but with nonfunctional computers, or for collecting and processing data for any other Fourier transform spectrometers.