HOLOGRAPHY

Holography was invented in 1948 by Hungarian physicist Dennis Gabor (1900-1979), for which he received the Nobel Prize in physics in 1971. He received patent GB685286 on the invention. The discovery was an unexpected result of research into improving electron microscopes at the British Thomson-Houston Company in Rugby, England, but the field did not really advance until the invention of the laser in 1960.
First of all the question is What is HOLOGRAPHY?

In holography, one beam (the reference beam) comes directly from the laser, while the other (the object beam) comes from the same laser but impinges on the object, and is distorted by it, before striking the photographic film. What is recorded on the film is the interference pattern produced by the two beams. After development, if the hologram is illuminated by a beam of light from the direction of the reference beam, the object beam is recreated, and the object "appears."

A hologram is a three-dimensional picture .It is a recording of an interference pattern made by the interaction of two beams of light.

Laser light is used in holography because it has coherence. This means that the waves of light coming from the laser are not only of the same wavelength, but that all the waves are "in step", like soldiers marching together. White light, from the sun or a light bulb, is made up of many different wavelengths, so it is like a group of people walking along, some taking short strides, some longer ones, all out of step, and going in various directions.