The Design of Convex Grating for Civil Imaging Spectrometers

As the core element of concentric imaging spectrometers with convex grating, convex grating determines the performance of the instrument directly, it is also the key factor that restricts the development of this instrument. The design of convex grating is the prerequisite of the the design of its civil imaging spectrometers. In this paper, a civil convex grating was designed according to the application demand of civil imaging spectrometers. The numerical relationships between the structure parameters and the diffraction efficiency of the convex grating were studied with integral theory of diffraction gratings, then a convex grating which meet the actual need was designed. Through simulation and optimization, the rectangular groove depth of the convex grating is 150nm, and its line density is 150 g/mm, its duty ratio is 0.5. The test results shows that the rectangular convex grating meet actual demand of imaging spectrometers.