Hologramme

Hologramme is the French term for a hologram, a three-dimensional image produced by the technique of holography. A hologram records the light field of an object by interfering a reference beam with light scattered from the object, encoding both intensity and phase information into a photosensitive medium such as a photographic plate or a digital sensor. When illuminated with a compatible light field, the hologram can reconstruct a volumetric image that changes appearance with the observer’s perspective, providing depth cues not present in a flat photograph.

Technically, holography relies on coherent light, usually from a laser, and precise optical arrangements. There are transmission holograms, which require illumination from behind the holographic plate, and reflection holograms, which are viewed with light reflected off the surface. Digital holography and computer-generated holograms extend the concept by using computational methods to synthesize or reconstruct the holographic wavefront, enabling more flexible or interactive displays and data storage.

Historically, holography was introduced by Dennis Gabor in 1947 as a method to improve microscope imaging, with practical laser-based holography demonstrated in the 1960s by Emmett Leith, Yuri Denisyuk, and others. Since then, the technology has evolved into security features for banknotes and products, artistic installations, medical imaging research, and emerging consumer applications such as holographic displays and augmented reality.

Etymologically, the term derives from Greek holos meaning whole and gramma meaning write. In everyday usage, hologramme refers to the same concept as the English hologram, with regional spelling variations.