MacLaurin does not mention the possibility that the center of the series of diffraction rings produced when light is shone through a small hole may be black, but he does point to the inverse situation wherein the shadow produced by a small circular object can paradoxically have a bright center. As the gap becomes larger, the differentials between dark and light bands decrease until a diffraction effect can no longer be detected. If the gap is made progressively wider, then diffraction patterns with dark centers will alternate with diffraction patterns with bright centers. The result is that if the gap is very narrow only diffraction patterns with bright centers can occur. The wave front that proceeds from the slit and on to a detection screen some distance away very closely approximates a wave front originating across the area of the gap without regard to any minute interactions with the actual physical edge. He uses the Principle of Huygens to investigate, in classical terms, what transpires. MacLaurin explains Fresnel diffraction by asking what happens when light propagates, and how that process is affected when a barrier with a slit or hole in it is interposed in the beam produced by a distant source of light. In his monograph entitled "Light", Richard C. Some of the earliest work on what would become known as Fresnel diffraction was carried out by Francesco Maria Grimaldi in Italy in the 17th century. The example of Fresnel diffraction is near-field diffractionĮarly treatments of this phenomenon The multiple Fresnel diffraction at closely spaced periodical ridges ( ridged mirror) causes the specular reflection this effect can be used for atomic mirrors. Fresnel diffraction showing central Arago spot
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