LASERS AND THEI R APPLI CATI ONS HOLOGRAPHY AND OTHER 3 D METHODS OF ENTERTAI NMENT COMPILED BY HOWIE BAUM 1
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 2
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.
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 https://www.youtube.com/watch?v=0ics3RVSn9w commercially available. 4
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. 5
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. 6
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 7
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 •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. 9
Hologram properties 10
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. 11
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. 12
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. 13
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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. 17
HOLOGRAM MASTERING STATION COST: $31,250 !! 18
HOLOGRAM - USES FOR : AUTHENTICATION •Identity card •Passport •Sticker or Tag 19
IDENTICARD: PASSPORT: 20
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 . 21
STICKERS : 22
HOLOGRAPHI C COI NS 23
I RI DESCENT REFLECTI VE MATERI ALS 24
Virtual Displays: •Sci-fic movies •For trade-show booths •Museum displays 25
SCI-FIC MOVIES: 26
For trade-show booths: 27
HEADS-UP DISPLAY, IN PLANES AND NOW CARS 28
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. 29
PEPPER'S GHOST: HOW DEAD CELEBRITIES ARE BEING RECREATED AS REALISTIC “HOLOGRAMS” https://www.youtube.com/watch?v=1pjZ98p9k3c 30
EQUIPMENT USED TO SHOW AN IMAGE LIKE PEPPER’S GHOST https://www.youtube.com/watch?v=r27wrQOgawo 31
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Holographic interferom etry ( 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 ! 33
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 34
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 35 deformation.
ENDOSCOPI C 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 GASTRI C W ALL ELASTI CI TY ASSESSED shown the promise BY DYNAMI C HOLOGRAPHI C of real-time ENDOSCOPY observation of living biological specimens. 36
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 37
NEW VI RTUAL TECHNOLOGY COULD I MPROVE BRAI N SURGERY https://www.youtube.com/watch?v=n3mx7Rd-Yb4 38
https://www.youtube.com/watch?v=h4M6BTYRlKQ 39
LASERS https://www.youtube.com/watch?v=oUEbMjtWc-A 40
The most significant applications of lasers are in these areas: • Medicine • Communications • Manufacturing • Science and technology • Military 41
MEDI CI NE 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 42
COMMUNI CATI ONS 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 43
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