Abstract
A novel dual-band static Fourier transform imaging spectrometer was designed, which was the spatio-temporally modulated imaging Fourier transform spectrometer based on Sagnac interferometer. The approach represented a simplification and mass reduction over the traditional approach. It could obtain two-dimensional spatial images and one dimensional spectral image in two bands simultaneously. The two bands was separated through a dichroic prism and imaging in two detectors. one band was the visible and near infrared band, with the spectral range 400nm-1000nm and spectral resolution 187.5 wave numbers; the other was the short wave infrared band, with the spectral range 1000nm- 2500nm and spectral resolution 150 wave numbers. To reduce the size of the Interferometer, a high aperture compression ratio telescope system was designed before. The optical aperture was compressed to 1/10, and the volume of interferometer was reduced to 1/1000. For the convenience of engineering implementation, the telescope was composed of two no-aberration object lens: fore-lens and Collimating lens. The two band imaging spectrometers shared the primary lens and the second lens of the fore-lens and use their own collimating lens, interferometers and Fourier transform lens. The collimating lens and the Fourier transform lens of each spectrometer could be designed to the same structural style and parameters. The both spectrometers had a focal length of 1000mm, F number of 5, FOV(field of view) of 1°. Moreover, both image qualities were close to the diffraction limit, the distortion was less than 2%. The advantage of the instrument was that dual band spectral image could be acquired at the same time and the interferometer was miniaturized extremely in the case of unchanged technical indicators.
