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Applications of Lasers

HOLOGRAPHY

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Content Birth of hologramPreparation of hologramReconstruction of hologramUses of hologram Future scope of holography

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o In 1947, English physicist Dennis Gabor tried to improve the image-producing capability of electron microscopes, which use streams of electrons rather than light to magnify objects.

o His solution was to take an electron "picture" of an object. However, this process required a coherent light source—something that did not exist at the time.

o It wasn't until the early 1960s, when the first working laser was produced, that 3-D images could be created.

o For developing the basic principles of holography, Gabor was awarded the Nobel Prize in 1971.

Birth of the hologram

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Two steps of image formation a) Hologram: The object is transformed into a photographic record.

b) Reconstruction: The hologram is transformed into the image. No lens is needed in either step!!A method of obtaining three-dimensional photographic images. These images are obtained without a lens, so the method is also called lens less photography. The records are called holograms.

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Hologram and HolographyHolography is a method of producing a three-

dimensional (3-D) image of an object. (The three dimensions are height, width, and depth.)

The image it brings to life is referred to as a hologram, from the Greek word meaning "whole picture." Unlike a two-dimensional picture, a hologram allows a person to look "around" and "behind" its subject.

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o The hologram is actually a recording of the difference between two beams of coherent light.

o Light is composed of waves that are all the same length and that travel in all directions. Coherent light is in phase, meaning its waves are vibrating and traveling together in the same direction.

o To create a hologram, a laser beam (coherent light) is split in two: one beam that stays undisturbed, called the reference beam, strikes a photographic plate.

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o The second beam, called the object beam, strikes the subject and then bounces onto the plate.

o The subject's interfering with the second beam causes the two beams to become out of phase.

o This difference called phase interference is what is recorded on the photographic plate.

o When a hologram is later illuminated with coherent light of the same frequency that created it, a three-dimensional image of the subject appears.

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Uses for hologramso One of the most visible

applications of holography is in the field of advertising. Holograms can be found on the covers of magazines, books, and music recordings.

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o In the 1970s, automakers would often use cylindrical holograms to show a new car model. A prospective car buyer could walk around the tube and view the vehicle from all angles, though the cylinder was actually empty.

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o The medical field was also quick to find a use for holograms. A holographic picture could be taken for research, enabling many doctors to examine a subject in three dimensions.

o Also, holograms can "jump" mediums, that is, a hologram made using X rays can be viewed later in white light with increased magnification and depth.o A critical application of holography is in computer data storage. Magnetic disks, the most common storage device for home and small-frame computers, is two dimensional, so its storage capacity is limited.

o Because of its three-dimensional nature, a hologram can store much more information. Optical memories store large amounts of binary data (with series of zeroes and ones representing bits of information) on groupings of small holograms. When viewed by the computer using coherent light, these groupings reveal a 3-D image full of information.

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o To study the rare species ,and extinct species .

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3D Hologram and the Future of Technology and Entertainment

If you ask me what I consider the best part of 3D, then my reply would be 3D holography. What I like most about this new and exotic technology hailing from 3D is it gathers together a number of futuristic and technologically superior trends into a compact form that could be mind-numbing at times.

3D holography hasn’t yet grown up, in fact it is still far from growing up. But my hunch is within ten or fifteen years from now, we are going to see some real improvements. What compels me have this hunch are the recent developments that are awe-inspiring. Different commercial segments importing 3D solutions, 3D making inroads into digital art and scientific concepts are being applied by the technologists.

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o There are some really trendy technologies that belong to the 3D holographic . There’s another technology, which is called touchable hologram. It runs a software that relies on ultrasonic waves, and the user who is touching the projected hologram, feels a pressure on his hand.

o Holographic TV is perhaps going to be the biggest of surprises. Researchers at MIT are anticipating holographic TV could enter our drawing room in just ten years down the line. If it turned into a valid anticipation, then today’s 2D TV sets would be obsolete from the market.

o The laser plasma technology could give 3D an altogether new shape. Aerial Burton has used plasma laser to have 3D images floated in the air. The technology is in its nascent stage currently but it has plenty of rooms to prosper in the future. Technologies such as plasma laser work in a fascinating way, it accounts for opaqueness. Using this technology, light could be viewed without it having to bounce off a surface.

3D holographic technologies

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