PHASE CORRECTION IN FOURIER-TRANSFORM SPECTROSCOPY - SUBSEQUENT DISPLACEMENT CORRECTION AND ERROR LIMIT

Fourier transform spectroscopy interferograms are apodized prior to th e transformation and the calculated spectrum is phase corrected. If th e zero point for the Fourier transformation is displaced. a phase erro r occurs because the apodization remains fixed while the interferogram is shifted bg the phase correction. A theoretical description of this effect is derived and an algorithm for subsequent removal is provided . It is also reported that fixing the zero point to solely the samplin g positions leads to error in the band shape that by far exceeds the n oise and therefore limits the spectroscopic accuracy. (C) 1997 Optical Society of America.