Based on flat field diffraction gratings and array detectors

the optics and structures of a Shortwave Infrared(SWIR) field spectroradiometer were designed.The spectroradiometer comprises of two cells and guides light by fiber optic to simplify the optical designs of system and structure. In order to make two cells have the same Field of View(FOV)

a pre-optical system was designed to ensure the radiance of any point in the FOV for illuminating all fibers uniformly. The FOV can be changed with different pre-optical systems also. Based on the relation of the luminous flux and the spectral resolution with incidence slit

the size of slit was educed. The spectral range of radiometer is 900~2 400 nm with the resolution better than 12 nm. Experimental results show that the instrument can meet the requirements in field measurements.