Ratio Method of Fourier Spectrometry: an mprovement.
If the two detectors of a ratioing dual-beam interferometer do not have identical spectral responses, the sum of the two signals will have undesirable residual fringes; a spectrum derived from the ratio of the difference of the two signals to the sum will be distorted. Our technique allows removal of these fringes with only a small effect on any other modulation (such as source intensity modulation) in the sum signal. We find the average ratio of the sum fringe spectrum to the difference spectrum. Multiplying this average ratio by the spectrum from an arbitrary difference interferogram predicts the expected fringes in the sum signal, which can then be removed.
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Ahern
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Pritchet