Introduction

Holography is closely linked to the undulatory nature of light. Indeed the latter is explained using the principles of diffraction and interferences.

Holograms are defined by the interference between two waves, the “object wave” and the “reference wave”. A misuse of language has meant that holograms are often defined as being the stereoscopic image seen by the observer. In reality; the hologram is defined as being the interferential pattern of the combination of the two previously mentioned waves.

This pattern contains the information, stored as complex amplitude, of the studied object field; thus, it is possible to reconstruct the object field in its entirety, both amplitude and phase, from the holographic plate. It is the phase information which makes it possible to reconstruct the contours of the object, and to recreate the parallax. The reconstruction of the recorded image is linked to the occurrence of diffraction.