Well, we must have seen the supermarket and department store scanners use a holographic lens system that directs laser light onto the bar codes of the merchandise.

But what exactly is holography?

Holography is a method of producing three- dimensional images of objects employing the coherence properties of laser beams. The technique was proposed by Gabor in 1947. In this technique, the amplitude information and the phase information of the light reflected from an object, i.e. an encoded image of the object is recorded on a photographic plate, referred to as the hologram. Subsequently, the hologram is decoded by a read-out light wave to produce the three- dimensional image, which manifests vivid realism.

Holography involves two steps:

I)Recording of the hologram

II)Reconstructing the image

Features of Holography

• The virtual image of a hologram is three-dimensional. By tilting its head, the observer can see the details which were not visible before. The image is thus more realistic.

• The damage of a portion of a conventional photographic image causes a permanent loss of information for that part of the object.

• The information capacity of a hologram is tremendous. The superposition of a number of images on a photographic plate in conventional photography is meaningless.

• In a hologram copied from another by contact printing, the transparent areas of the original become opaque, and vice versa. Hence the copied hologram is the reverse of the original.

Some current applications that use holographic technology are:

• The use of holograms on credit cards and debit cards provide added security to minimize counterfeiting.

• Holographic optical elements (HOE’s) are used for navigation by airplane pilots.

• Medical doctors can use three- dimensional holographic CAT scans to make measurements without invasive surgery.

• Sony Electronics uses holographic technology in their digital cameras.

Sources / References [If Any] : Internet