Optical path squeezing interferometry: boosting the resolution for Fourier transform imaging spectrometers

We present an optical path squeezing interferometer dedicated to high-spectral-resolution Fourier transform imaging spectrometry. By incorporating a pair of gratings into a Sagnac interferometer, the short-wavelength light has a larger optical path difference (OPD) than the long-wavelength light. Interference fringes with different OPDs are squeezed into the same sampling window in data acquisition. As a result, the spectral resolution is greatly enhanced without large OPD scanning. The experimental results demonstrate that the proposed method is a promising technology for high-resolution spectral imaging. (C) 2016 Optical Society of America