Using the relation for the irradiance due to the interference of point sources, we show through graphs how the Huygens-Fresnel principle works when it is applied to determine the Fraunhofer diffraction pattern due to a normally incident plane wave on a single slit. In this way, we are able to identify the origins of the principal and secondary peaks of diffraction, which is not clearly understood from the analytical determination of the present diffraction pattern.
diffraction; Huygens-Fresnel principle; visualization
