Correction of instrument line shape distorsions in Fourier transform spectroscopy as a phase error correction problem

A recovery procedure has been developed to correct instrument line-shape distortions observed in Fourier transform spectroscopy. The procedure can be described as a phase-error correction performed in the spectral domain to correct for path-difference-dependent phase errors observed in sharp spectral features. The technique has been applied successfully to high-resolution atmospheric emission spectra. The inherent broadening of the real features has been separated accurately from instrumental distortions. Using models for the path-difference-dependent error sources and data from two narrow window regions at 50 and 118 cm-1, we show that the distortion has a simple dependence on the spectral frequency.