ABSTRACT
Recall that geometrical optics deals with the properties of light when it encounters objects, mirrors, lenses, and orifices that are large compared with its wavelength. Physical or wave optics addresses light behavior when it encounters objects that are approximately the same size or that are smaller than its wavelength. It is in this realm that light exhibits its wave nature and a wave description of light is appropriate. Under these conditions, the two main manifestations of light behavior are called interference and diffraction. These two phenomena are consequences of a very general principle called the linear superposition principle (LSP).
