The holodiagram in a geometrical approach to the calculation of fringes visibility

Abstract

This work is intended as a help to show, using very simple geometrical models, how visibility is built into the Young's interference patterns produced by incoherent sources. A very simple example, that consisting in only two mutually incoherent point sources, is used. Consonance between independent fringe systems leads straightforwardly to the same results predicted by the Van Cittert-Zernike's Theorem. The homogeneous and non-homogeneous cases are exemplified. Abramson's Holodiagram, both the classic one and the Young's fringes one, concepts are then used to gain further non trivial insight in some simple situations including that of virtual sources. Sensitivity to pinholes displacements and areas of homogeneity are easily observed.