Research on suppression method of straight edge diffraction effect of mosaic grating

The diffraction characteristics of amplitude and phase-type soft-edge apertures with super-Gaussian transmittance at the gap of mosaic grating are investigated in this article. A well-designed soft-edge apertures can effectively suppress the Fresnel straight-edge diffraction intensity distribution at a certain transmission distance and consequently homogenize the overall light intensity on the image plane. We use the PV value, which is the difference between the maximum intensity of Fresnel diffraction and the initial incident intensity, as the evaluation index of diffraction intensity homogenization. Compared with use of the hard-edge aperture, the PV value reduces from 0.6 to 0.009 and 0.051 at the distance of 0.5m and 1m respectively with use of the super-Gaussian amplitude type soft-edge apertures designed by us. While using the super-Gaussian phase type soft-edge apertures designed by us, the PV value reduces from 0.6 to 0.053 and 0.06 at the distance of 0.5m and 1m respectively.