LASERS AND THEIR APPLICATIONS

HOLOGRAPHY AND OTHER 3D METHODS OF ENTERTAINMENT

1COMPILED BY HOWIE BAUM

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Princess Leia pleas for help in their struggle against the Empire, in a holographic message played by the robot, R2-D2.

https://www.starwars.com/video/help-me-obi-wan-kenobi

History of Holography

Holography was invented in 1947 by Hungarian physicist Dennis Gabor (1900–1979), work for which he received the Nobel Prize in Physics in 1971.

Gabor's research focused on electron optics, which led him to the invention of holography.

The basic idea was that for perfect optical imaging, the total of all the information has to be used; not only the amplitude, as in usual optical imaging, but also the phase of the light waves.

In this way, a complete 3- dimensional picture can be obtained.

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At the time Gabor developed holography, coherent light sources, such as a laser, were not available, so the theory had to wait more than a decade until its first practical applications were realized.

He experimented with a heavily filtered mercury arc light source.

The invention in 1960 of the laser, the first coherent light source, was followed by the first hologram, in 1963, after which holography became commercially available.

https://www.youtube.com/watch?v=0ics3RVSn9w

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HOLOGRAPHY IS A TWO-STAGE PROCESS OF PHOTOGRAPHY USING COHERENT LIGHT FROM A LASER

TO ILLUMINATE THE SCENE

1) In the first stage a hologram is formed by combining the light scattered from the object and the direct laser beam on a photographic plate.

2) In the second stage a three-dimensional image is reconstructed without the use of lenses, by directing the laser beam through the hologram.

Applications of holography include:

Information storage

Recording of images in depth – a virtual display

The use of holograms as optical elements

As a means of performing precise measurements on three-dimensional objects of any shape and surface finish.

Holography: Means

•Holography (from the Greek, whole + write) is the science of producing holograms

•Holes-Whole and Gramma-message

• It is an advanced form of photography that allows an image to be recorded in three dimensions.

•The technique of holography can also be used to optically store, retrieve, and process information.

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Conventional vs. Holographic photography• In conventional photography:

•It is a 2- dimensional image of a 3- dimensional scene

•The photograph lacks depth perception

•The regular film is sensitive only to light energy

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Conventional vs. Holographic photography

•A Hologram:

•Freezes the intricate wave front of light that carries all the visual information of the scene.

•To view a hologram, the wavefront is reconstructed

•The view is what we would have seen if we were present at the original scene, through the window defined by the hologram.

•Provides depth perception 8

Hologram properties

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• If you look at these holograms from different angles, you see objects from different perspectives, just like you would if you were looking at a real object

•They usually just look like sparkly pictures or smears of color

• If you cut one in half, each half contains whole views of the entire holographic image.

Hologram properties

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Hologram construction

•The method to make them requires a specific setup using lasers, a prism, and mirrors.

•Laser : Red lasers, usually helium-neon lasers, are common in holography

•Beam splitter: This is a device that uses mirrors and prisms to split one beam of light into two beams.

•Mirrors: These direct the beams of light to the correct locations.

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Hologram construction

•Holographic film:

•Holographic film can record light at a very high resolution, which is necessary for creating a hologram.

•It's a layer of light-sensitive compounds on a transparent surface, like photographic film.

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Why a Laser ?• Lasers produce monochromatic (only 1 color) light -- it has one wavelength and one color.

• It is coherent which means that it travels only in a straight line.

• A laser has to be used because of the need for coherent interference between the reference and object beams.

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Close-up photograph of a hologram's surface.

The object in the hologram is a toy van.

It is no more possible to see the subject of a hologram from this pattern than it is to identify what music has been recorded by looking at a CD surface.

Note that the hologram is described by the speckle pattern, rather than the "wavy" line pattern.

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HOLOGRAM MASTERING STATION

COST: $31,250 !!

HOLOGRAM - USES FOR : AUTHENTICATION

•Identity card

•Passport

•Sticker or Tag

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IDENTICARD:

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PASSPORT:

WHY ARE HOLOGRAMS USED FOR AUTHENTICATION ?

•Hologram stickers cannot be scanned or photocopied.

•Hologram stickers can also create a unique and attractive complement to existing packaging and product.

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STICKERS:

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HOLOGRAPHICCOINS

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IRIDESCENT REFLECTIVE MATERIALS

Virtual Displays:

•Sci-fic movies

•For trade-show booths

•Museum displays

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SCI-FIC MOVIES:

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For trade-show booths:

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HEADS-UP DISPLAY, IN PLANES AND NOW CARS

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In 1860, more than 150 years ago, Pepper’s Ghost, an illusionary trick created by John Henry Pepper, was developed to make it appear that a ghost was part of a play.

By means of a sheet of glass, special lighting, and using the reflective properties of the glass, the impression or optical illusion is created that objects or persons appear and disappear.

30https://www.youtube.com/watch?v=1pjZ98p9k3c

PEPPER'S GHOST: HOW DEAD CELEBRITIES ARE BEING RECREATED AS REALISTIC “HOLOGRAMS”

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EQUIPMENT USED TO SHOW AN IMAGE LIKE PEPPER’S GHOST

https://www.youtube.com/watch?v=r27wrQOgawo

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Holographic interferometry (HI) is a technique which enables static and dynamic displacements (vibrations) of objects with optically rough surfaces to be measured to optical precision (to fractions of a wavelength of light).

These measurements can be applied to stress, strain and vibration analysis, as well as to non-destructive testing and radiation dosimetry.

The HI image below shows the areas of vibration in a guitar !

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Holographic interferometry techniques have been widely applied with success for the study of different parts of the human body including:

Cornea

Tooth mobility

Tympanic membrane

Basilar membrane

Cochlea

Temporal bone

Incudo-malleolar joint

Chest

Skull

Bones

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GEARBOX RESEARCH.

Technician testing an engine gearbox (green) using holographic interferometry as part of a development program.

This non-destructive test shows the change in shape of the gearbox casing during operation.

A laser beam is shone through a reference hologram of the gearbox and onto the gearbox itself.

The areas of deformation appear as a series of dark lines (an interference pattern). The pattern can be recorded and analysed to determine the amount of deformation.

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ENDOSCOPIC HOLOGRAPHY

It is a powerful tool for non-contact, high resolution imaging and non-destructive measurements inside the natural cavities of human or animal internal organs.

Holography has shown the promise of real-time observation of living biological specimens.

GASTRIC WALL ELASTICITY ASSESSED BY DYNAMIC HOLOGRAPHIC

ENDOSCOPY

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THE HOLOLENS

Microsoft’s Hololens is a device that gives you views of a 3-dimensional Alternate Reality, when you look at the area around you.

They say you are seeing Holograms but you aren’t.

The headset is able to project virtual images on top of the real world.

https://www.youtube.com/watch?v=cCL3bFuC4IA

NEW VIRTUAL TECHNOLOGY COULD IMPROVE BRAIN SURGERY

38https://www.youtube.com/watch?v=n3mx7Rd-Yb4

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https://www.youtube.com/watch?v=h4M6BTYRlKQ

40https://www.youtube.com/watch?v=oUEbMjtWc-A

LASERS

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The most significant applications of lasers are in these areas:

• Medicine

• Communications

• Manufacturing

• Science and technology

• Military

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MEDICINE

Bloodless surgery

Destroy kidney stones

Cancer diagnosis and therapy

Eye lens curvature corrections

Fiber-optic endoscope to detect ulcers in the intestines

Liver and lung diseases could be treated by using lasers

Study the internal structure of microorganisms and cells

Remove tumors successfully

Remove the caries or decayed portion of the teeth

Cosmetic treatments such as acne removal, cellulite and hair removal

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COMMUNICATIONS

1. Optical fiber communications to send information over large distances with low loss

2. Laser light is used in underwater communication networks

3. Space communication, radar, and satellites

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MANUFACTURING

1. Cut glass, quartz, and metal plate

2. Electronic industries for trimming the components of Integrated Circuits (ICs)

3. Heat treatment in the automotive industry.

4. Laser light is used to scan and collect the information from the bar code printed on products.

5. The semiconductor industries for photolithography to make printed circuit boards (PCB) and microprocessors by using ultraviolet light.

6. Drill aerosol nozzles and control orifices with the required precision.

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SCIENCE AND TECHNOLOGY

1) A laser helps in studying the Brownian motion of particles

2) With the help of a helium-neon laser, it was proved that the velocity of light is same in all directions

3) With the help of a laser, it is possible to count the number of atoms in a substance

4) Used on computers to retrieve stored information from a Compact Disc (CD), DVD, or Blu-Ray disc

5) Store large amount of information or data on a CD-ROM

CD DVD BLU-RAY

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SCIENCE AND TECHNOLOGY (CONTINUED)

1) Measure the pollutant gases and other contaminants of the atmosphere

2) Lasers helps in determining the rate of rotation of the earth accurately

3) Computer printers

4) Producing three-dimensional pictures in space without the use of lens

5) Detecting earthquakes and underwater nuclear blasts

6) A gallium arsenide diode laser can be used to setup an invisible fence to protect an area

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MILITARY AND CARS

1) Laser range finders are used to determine the distance to an object

2) The ring laser gyroscope is used for sensing and measuring very small angle of rotation of the moving objects

3) Lasers can be used as a secretive illuminators for reconnaissance during night with high precision

4) Remove the energy of a warhead by damaging a missile

5) Laser light is used in LIDAR’s to accurately measure the distance to an object, which is used in some autonomous vehicles

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THE END