ABSTRACT
This chapter starts by introducing generalities that allow us to establish the necessary conditions for interference. It also introduces the different ways to observe interference phenomena. These are mainly divided in two parts, wavefront division and amplitude division interferometry. For both of these, the sources of light are assumed to be point sources and monochromatic. This hypothesis simplifies considerably the description of issues, e.g., the localization of the fringes. The chapter discusses incoherent sources with spatial and spectral extension. It focuses on the interaction between two waves only in order to simply highlight the main factors that reveal the interference. The Lloyd mirror consists of a mirror placed between the source plane and the observation screen plane and arranged perpendicularly to both of them. The source consists of a slit assumed to be infinitely thin and arranged perpendicularly to the plane of the figure.
