Optical path difference measurement for high resolution Fourier spectrometer

Two kinds of laser source interferometer (polarizing and absorbing beamsplitter) used for the accurate measurement of the optical path difference of a Fourier transform spectrometer are described and compared. The two interferometer configurations have been used with aircraft- and balloon-borne far-infrared spectrometers for atmospheric limb-sounding measurements, SAFIRE-A and IBEX. A comparison of the two implementations is described in this paper, and the relative performances and merits are compared.