Geometric theory of Fresnel diffraction patterns - Part II. Rectilinear boundaries
In this paper, the Fresnel diffraction patterns of apertures and obstacles having rectilinear boundaries are discussed. Photographs of the patterns in a number of cases such as a square and an equilateral triangle are reproduced. These are explained in terms of the ideas developed in the first paper of this series. The transition from the Fresnel to the Fraunhofer class with square and equilateral triangular apertures is illustrated by means of photographs taken with apertures of decreasing size.