Static Fourier transform spectroscopy with enhanced resolving power

Static Fourier transform (StFT) spectrometers, as well as multichannel dispersive spectrometers, normally have a small value for the product of resolving power and relative free spectral range. This value is limited by the number of pixels in a row of the detector array used by the spectrometer. A method of increasing the resolving power of static Fourier transform spectrometers, while preserving their wide free spectral range, is proposed. The technique introduces a stepped retardation into a double-beam interferometer with a two-dimensional detector array. Several configurations of StFT spectrometers with stepped retardation are presented and the theoretical model, performance limitations and experimental results are discussed. The possibility of achieving large values of resolving power is demonstrated.