holographic

Holographic is an adjective relating to holography, a technique for recording and reconstructing the light field of an object so that the reconstructed image appears three-dimensional. The term derives from hologram, from Greek holo- meaning “whole” and -gram meaning “written.” The method was conceived by Dennis Gabor in 1947 to improve electron microscopy, and its principles were demonstrated with laser light in the early 1960s by Emmett Leith and Juris Upatnieks.

A hologram records the interference pattern between light reflected by the object (the object wave) and a reference beam. When illuminated by coherent light, the hologram diffracts light to recreate the original light wave, including phase information, enabling a three-dimensional image to be viewed from different angles. There are transmission holograms and reflection holograms, as well as computer-generated holograms that simulate the same principles using digital data.

Applications of holography include security: holograms are widely used on banknotes, credit cards, and identity documents to deter counterfeiting. In art, science, and industry, holography supports imaging, data storage research, interferometry, and metrology. Modern work includes holographic displays and volumetric or light-field displays designed to present 3D images without eyewear, as well as holographic microscopy for detailed imaging of microscopic samples.

In physics, the holographic principle posits that a volume of space can be described by information on its boundary, linking theories of gravity in a higher-dimensional space to quantum field theories on the boundary. While influential, it remains a theoretical framework rather than a directly optical phenomenon, derived from ideas in string theory and quantum gravity.