Fig. 1. Working principle of grating in Camera of Sky Survey

Fig. 2. Diffraction efficiency of gratings with different grooves. (a)＋1 order diffraction efficiency; (b) 0 order efficiency

Fig. 3. Diffraction efficiency of grating under different parameters. (a) Under different incident angles; (b) under different polarization states

Fig. 4. Grating groove characterization parameters

Fig. 5. Relationship between diffraction efficiency of grating with different characterization parameters of groove. (a) Relationship between average diffraction efficiency with α and β；(b) relationship between peak diffraction efficiency with H and τ

Fig. 6. Peak wavelength versus H and τ

Fig. 7. Contour lines between diffraction efficiency of grating and different groove parameters. (a) Contour lines between peak diffraction efficiency with left and right angles; (b) contour line between average diffraction efficiency with left and right angles

Fig. 8. Test results of gratings fabricated by old process. (a) Scanning electron microscopy (SEM) image of another experimental grating fabricated by old process; (b) atomic force microscopy (AFM) tested groove of G1 grating; (c) measured height of each sampling point in one period of G1 grating; (d) measured diffraction efficiency of G1 grating

Fig. 9. Test results of G2 grating. (a) AFM image of groove; (b) SEM image of groove; (c) measured height of each sampling point in one period; (d) measured and predicted diffraction efficiencies

Fig. 10. Wavefront test result