Holography, coming from the Greek words holos (whole) and grafe (writing), is a form of photography that allows an image to be recorded in 3D. Discovered in 1948 by Hungarian born Dennis Gabor (1900-1979) while working for the Thomson-Houston company in Rugby, England, its early development was hampered by insufficient light sources.
Gabor's holography stored 3D images by encoding them within a beam of light, but the mercury arc lamp he used produced variable results. The invention of the laser by a team of Russian and U.S. scientists in 1960 provided a pure, intense light that was ideal for creating holograms. The pulsed-ruby laser emits a very powerful burst of light that lasts a few nanoseconds and effectively freezes movement.
The development of the laser enabled the first experiments in optically storing and retrieving images. The first laser-transmission hologram of 3D objects, a toy train and a bird, occurred in 1962. Stephen A.
Benton invented white-light-transmission holography In 1968, and this form finally enabled mass production. Benton's technique meant that, when viewed in ordinary white light, the hologram created a three- dimensional "rainbow" image from the seven colors that make up white light.
The use of holograms in every form is widespread. Rainbow holograms are used on credit cards, artists such as Salvador Dali employed holography artistically, and holograms also appeared in some of the movies that defined the latter half of the twentieth century. Where would Star Wars be without a 3D Princess Leia begging for help, or the swoosh of a light saber?
