What is Holography? Holography is a technique which enables three-dimensional images to be made. It involves the use of a laser, interference, diffraction,light intensity recording and suitable illumination of therecording. The image changes as the position and orientation of theviewing system changes in exactly the same way as if theobject were still present, thus making the image appear three-dimensional.
Holography or ‘Lens less photography’ Holography is a technique that enables a light field, which is generally the product ofa light source scattered off objects, to be recorded and later reconstructed when theoriginal light field is no longer present, due to the absence of the original objects. There are two physical phenomena as the principles of the holography: interferenceand diffraction of light waves. When the two laser beams reach the recording medium, their light waves intersectand interfere with each other. It is this interference pattern that is imprinted on therecording medium. The pattern itself is seemingly random, as it represents the way inwhich the scenes light interfered with the original light source — but not the originallight source itself. The interference pattern can be considered an encoded version ofthe scene, requiring a particular key — the original light source — in order to view itscontents.
Planar view of interference pattern
Formation of Hologram
Holography –Current andFutureApplications
Current Applications Holographic interferometry is used by researchers and industry designers totest and design many things, from tires and engines to prosthetic limbs andartificial bones and joints. Supermarket and department store scanners use a holographic lens systemthat directs laser light onto the bar codes of the merchandise. Holographic optical elements (HOE’s) are used for navigation by airplanepilots. A holographic image of the cockpit instruments appears to float infront of the windshield. This allows the pilot to keep his eyes on the runwayor the sky while reading the instruments. This feature is available on somemodels of automobiles.
Holograms are used in advertisementsand consumer packaging of products toattract potential buyers. The use of holograms on credit cards anddebit cards provide added security tominimize counterfeiting.. Sony Electronics uses holographictechnology in their digital cameras. Aholographic crystal is used to allow thecamera to detect the edge of the subjectand differentiate between it and thebackground. As a result, the camera isable to focus accurately in darkconditions.
Future Application Future colour liquid crystal displays (LCD’s) will be brighter andwhiter as a result of holographic technology. Scientists at PolaroidCorp. have developed a holographic reflector that will reflect ambientlight to produce a whiter background. Holographic night vision goggles. Holographic memory is a new optical storage method that can store 1terabyte (= 1000 GB) of data in a crystal approximately the size of asugar cube. In comparison, current methods of storage include CD’sthat hold 650 to 700 MB, DVD’s that store 4.7 GB, and computer harddrives that hold up to 120 GB. Optical computers will be capable of delivering trillions of bits ofinformation faster than the latest computers.
Future of holography Holography is a very usefultool in architecture. Use of holography inarchitecture is recording ofmodels and previsualisenew buildings. It can provide attractivemethod to traditionalmethods in sales andpresentation.
Advancedlaser, optics, imageprocessing are incorporatedinto Zebra 3D imaging toproduce Holography images. This holography is possible tocreate large city maps, fullseized cars, humans, andmachines