Analysis on light intensity distribution of diffraction of "unequal slit width" gratings

Taking gratings with periodically varying slit width as two groups of diffraction hinge unit, light radiates on the gratings, each diffraction unit produces diffraction respectively, and then it is equivalent to interference of two beams of coherent light. Using the theory of light diffraction and interference, by means of the diffraction light intensity distribution function of equal slit width, the light intensity distribution law of Fraunhofer diffraction is analyzed for transmission grating of periodically varying slit width. Based on the discussion of general results obtained, the diffraction light intensity distribution and light-shade stripe conditions are obtained for gratings with special slit width and nick width, the diffraction pattern and light intensity distribution curves are plotted through computer simulation.