Plane-grating diffraction is an important part of the couses of Optics and College Physics, both of which are the re quired courses for the majors in physics and other science and engineering majors, respectively. This paper utilizes the idea of ＂equivalent beam＂ to analyze the phenomenon of plane-grating diffraction. Such a method can help us not only to simply obtain the distribution feature of the light intensity in a simple way, but also to better understand the modulation effect of the Fraun- hof...
