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Convex grating imaging spectrograph with light weight and high fidelity

The optimized design, alignment and experimental results of a compact convex grating hyper-spectral imager with high fidelity are reported and evaluated. The imager works in visible wavelength range from 0.4 to 0.78 μm. The numerical aperture of system is 0.2, and the entrance slit images with -1 magnification and linearly dispersed into 7.5mm in width. In addition, the spectral sample resolution is 0.76nm/pixel with negligible distortion. In order to get good performance and facilitate alignment, the optical system is both imagery and objective telecentric. The efficiency of the convex grating can up to about 40 percents by ion-beam etching. The size is 190mm×180mm×90mm and the mass is less than 1kg. The light weighted compact system is portable, and it is feasible in remote sensing.