Holograms are a bit like photographs that never die. They’re sort of photographic ghosts: they look like three dimensional photos that have somehow got trapped inside glass, plastic, or metal. When you tilt a credit card hologram, you see an image of something like a bird moving “inside” the card.
The hologram itself is not an image and it is usually unintelligible when viewed under diffuse ambient light. It is an encoding of the light field as an interference pattern of seemingly random variations in the opacity, density, or surface profile of the photographic medium.
The theory of holography was developed by Dennis Gabor in 1947. The development of laser technology made holography possible.
A holographic image can be seen by looking into an illuminated holographic print or by shining a laser through a hologram and projecting the image onto a screen.
Holography is the science and practice of making holograms.
How to Work Hologram?
Laser light is much purer than the ordinary light in a torch beam. In a torch beam, all the light waves are random and jumbled up. Light in a torch beam runs along any old how, like schoolchildren racing down a corridor when the bell goes for home time.
In laser holography, the hologram is recorded using a source of laser light, which is very pure in its color and orderly in its composition.
A hologram can be made by shining part of the light beam directly into the recording medium, and the other part onto the object in such a way that some of the scattered light falls onto the recording medium. A more flexible arrangement for recording a hologram requires the laser beam to be aimed through a series of elements that change it in different ways.
When the two laser beams reach the recording medium, their light waves intersect and interfere with each other. It is this interference pattern that is imprinted on the recording medium.
A hologram represents a recording of information regarding the light that came from the original scene as scattered in a range of directions rather than from only one direction, as in a photograph. This allows the scene to be viewed from a range of different angles, as if it were still present.
A holographic recording requires a second light beam to be directed onto the recording medium.
Holography is the next stage of photography and conventional film and its three-dimensionality creates completely new possibilities for use, such as for product presentation.
A 3D hologram displays products, objects, and animated sequences three dimensionally and enables seemingly real objects or animations to appear to float completely freely in space.
A particularly interesting point unlike 3D television or Virtual Reality, a 3D hologram can be seen by everyone without 3D glasses, which is an incredible advantage for use at trade fairs, exhibitions, and similar events.
A Hologram projector, which makes the holographic 3D projection possible.