Heterodyne Fourier transform spectroscopy based on double-grating frequency shifter

A heterodyne Fourier transform spectroscopy is proposed in which a double-grating frequency shifter was used to provide the stable achromatic frequency shift. Compared with conventional Fourier transform spectroscopy, our method can obtain spectra with high sensitivity due to optical frequency modulation and high wavelength resolution due to there being no limit for its scanning range. A wavelength resolution of 0.16 nm was achieved in the spectra measurements.