Holography was invented in 1947 by the Hungarian-British physicist Dennis Gabor (Hungarian name: Gábor Dénes), work for which he received the Nobel Prize in Physics in 1971. Pioneering work in the field of physics by other scientists including Mieczysław Wolfke resolved technical issues that previously had prevented advancement. The discovery was an unexpected result of research into improving electron microscopes at the British Thomson-Houston Company in Rugby, England, and the company filed a patent in December 1947 (patent GB685286). The technique as originally invented is still used in electron microscopy, where it is known as electron holography, but holography as a light-optical technique did not really advance until the development of the laser in 1960.

The first practical optical holograms that recorded 3D objects were made in 1962 by Yuri Denisyuk in the Soviet Union and by Emmett Leith and Juris Upatnieks at University of Michigan, USA.Advances in photochemical processing techniques to produce high-quality display holograms were achieved by Nicholas J. Phillips.

Several types of holograms can be made. Transmission holograms, such as those produced by Leith and Upatnieks, are viewed by shining laser light through them and looking at the reconstructed image from the side of the hologram opposite the source. A later refinement, the "rainbow transmission" hologram, allows more convenient illumination by white light rather than by lasers. Rainbow holograms are commonly seen today on credit cards as a security feature and on product packaging. These versions of the rainbow transmission hologram are commonly formed as surface relief patterns in a plastic film, and they incorporate a reflective aluminum coating that provides the light from "behind" to reconstruct their imagery.

Another kind of common hologram, the reflection or Denisyuk hologram, is capable of multicolour-image reproduction, using a white-light illumination source on the same side of the hologram as the viewer.

Specular holography is a related technique for making three-dimensional imagery by controlling the motion of specularities on a two-dimensional surface. It works by reflectively or refractively manipulating bundles of light rays, whereas Gabor-style holography works by diffractively reconstructing wavefronts.

One of the most promising recent advances in the short history of holography has been the mass production of low-cost solid-state lasers, such as those found in millions of DVD recorders and used in other common applications, which are sometimes also useful for holography. These cheap, compact, solid-state lasers can, under some circumstances, compete well with the large, expensive gas lasers previously required to make holograms and are already helping to make holography much more accessible to low-budget researchers, artists and dedicated hobbyists.

It was thought that it would be possible to use X-rays to make holograms of molecules and view them using visible light. However, X-ray holograms have not been created to date.

Posted by : Research Site - 6 / 4 / 2011