Basic Concepts in Holography and Hologram Interferometry

Abstract

To understand how a different kind of lightning can be used in holography, in “lensless photography”, let us look at the nature of light in a little more details. Ordinary light is made up of many different wavelengths, none of which maintain a fixed phase relationship with each other, or with themselves, over a period of time. Saying in another way, it has poor temporal coherence; the waves at one point in the beam do not remain in step with the waves at some point in the beam further up stream. Such incoherent light does not scatter from objects in an orderly manner, and, most important for the application to holography, is not capable of interfering with itself.