What is a hologram?
In a photograph, the image of the object that you see on paper is a flat one. Holograms are different. They give a three-dimensional image of an object using the special light from a laser.
Unlike photography, which only records the brightness and contrast of any object, a hologram records brightness, contrast, and depth.
The first hologram was produced in 1948 by Dr. Dennis Gabor, a researcher at the Imperial College of London. Gabor's early holograms were created without the use of laser, since laser wasn't invented until 1960. Therefore, his holograms were only capable of showing the slightest amount of depth-about the thickness of a postage stamp.
With the invention of the laser in 1960, researchers finally had the proper type of light to begin recording an object dimensionally. These early holograms required laser to both record, and view the image. It wasn't long, however, before new techniques allowed the hologram, although still requiring a laser to record, to be viewed with ordinary light.
The expensive lasers of the past have been replaced by the inexpensive laser pointers of today, which makes creating a hologram quite easy.
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