Resolution limits in Fourier Transform Spectrometry

It is shown by mathematical analysis, and by close inspection of experimentally determined spectra, that the frequently quoted result Δ v̄= 0.5/ D, where D is the maximum path difference introduced, for the resolution in unapodized Fourier transform spectrometry is over optimistic. Even when the two lines are of equal strength the resolution is found to be Δ v̄ =0.7/ D whilst if they differ markedly in strength the resolution is even worse (∼ 0.8/ D). The loss in resolution in going to apodized spectrometry is not as severe as has previously been thought with Δ v̄ = 0.9/ D for equal strength components and Δ v̄ = 1/ D for the components having an intensity ratio of 2:1.