Static Fourier transform spectroscopy with enhanced resolving power

Static Fourier transform (StFT) spectrometers, as well as multichannel disp ersive spectrometers, normally have a small value for the product of resolv ing power and relative free spectral range. This value is limited by the nu mber of pixels in a row of the detector array used by the spectrometer. A m ethod of increasing the resolving power of static Fourier transform spectro meters, while preserving their wide free spectral range, is proposed. The t echnique introduces a stepped retardation into a double-beam interferometer with a two-dimensional detector array. Several configurations of SIFT spec trometers with stepped retardation are presented and the theoretical model, performance limitations and experimental results are discussed. The possib ility of achieving large values of resolving power is demonstrated.