Explain This: How do holograms work?

Question

If the tech world has taught us anything recently, it’s that very soon we’ll all have R2D2-style Holograms appearing all over our house. And we want that very much.

Except we’re not quite sure how they work. So we’re asking you..

#ExplainThis

Answer 1

A hologram is essentially a three-dimesional photograph. However, it takes much more work to make a hologram than it does for an ordinary two-dimensional photograph. To learn how holograms are made, we first need to learn a little about lasers.



Interference is what holograms are all about. A hologram is basically a reproduction of the "interference pattern" of laser light that's been shined on something. Let's say we had a coffee cup and we shone some laser light on it. However, we didn't shine all of the light on the cup. Some we diverted directly onto the photographic paper (the reference beam). The rest of the laser light (the object beam) shines on the cup, and is then reflected onto the paper. So we have light straight from the laser source and light that's been reflected from the cup. These two beams interfere with each other, causing a specific pattern of bright and dark spots where there has been constructive and destructive interference, spots where the waves added and subtracted.





It's the interference pattern that the photographic film records, unlike a regular photograph, which records the amount of light from a specific point (see the module on pinhole cameras for more information). Also, unlike the photograph, each point of the hologram contains all of the information from the object. So we could destroy almost all of our hologram and still reconstruct the image from a small piece. Try to do that with your regular photograph!



To see the hologram, we have to shine light that's just like the reference beam onto the photographic film after it's been developed. To see the hologram made from a laser, we need to use a similar laser. Now do you see why it's so hard to duplicate a hologram?!

Answer 2

Holograms such as those etched on a credit card are made with interference patterns and lasers, but that isn t the type shown on Star Wars and many other TV Programs and movies since.



You can use a trick called "Peppers Ghost" which uses an angles piece of glass to reflect the image from a screen, such an image will look to be floating in air, except there will be a sheet of glass in the space where the projection occurs.



Other tricks with mirrors can also be used to create the illusion of a object that is not actually there and some 3D TV technologies can allow you to see 3D without even wearing glasses.



But alas, in the end there is only one technology that will let you project light from some point in the air, and that is a flame.



However some efforts have been made to create objects that when rotated rapidly can be projected on in a 3D manner, but these still require a physical object in the space the image appears.



There might never be a practical technology to create a classic Sci-fi like Hologram, and the science behind the creation of one doesn t really exist.

Answer 3

Holography is the science and practice of making holograms. Normally, a hologram is a photographic recording of a light field, rather than of an image formed by a lens, and it is used to display a fully three-dimensional image of the holographed subject, which is seen without the aid of special glasses or other intermediate optics. The hologram itself is not an image and it is usually unintelligible when viewed by diffuse ambient light. It is an encoding of the light field as an interference pattern of seemingly random variations in the opacity, density, or surface profile of the photographic medium. When suitably lit, the interference pattern diffracts the light into a reproduction of the original light field and the objects that were in it appear to still be there, exhibiting visual depth cues such as parallax and perspective that change realistically with any change in the relative position of the observer.



In its pure form, holography requires the use of laser light for illuminating the subject and for viewing the finished hologram. In a side-by-side comparison under optimal conditions, a holographic image is visually indistinguishable from the actual subject, if the hologram and the subject are lit just as they were at the time of recording. A microscopic level of detail throughout the recorded volume of space can be reproduced. In common practice, however, major image quality compromises are made to eliminate the need for laser illumination when viewing the hologram, and sometimes, to the extent possible, also when making it. Holographic portraiture often resorts to a non-holographic intermediate imaging procedure, to avoid the hazardous high-powered pulsed lasers otherwise needed to optically "freeze" living subjects as perfectly as the extremely motion-intolerant holographic recording process requires. Holograms can now also be entirely computer-generated and show objects or scenes that never existed.



Holography should not be confused with lenticular and other earlier autostereoscopic 3D display technologies, which can produce superficially similar results but are based on conventional lens imaging. Stage illusions such as Pepper's Ghost and other unusual, baffling, or seemingly magical images are also often carelessly called holograms.

Answer 4

How Do Holograms Work

Answer 5

Holograms are formed from bending light. There are some versions of holograms that are projected onto a piece of glass such as the Microsoft Hololens. If your not a geek that the simplest way to explain holograms is OOOOO MAGIC

Answer 6

Holography is the science and practice of making holograms. Normally, a hologram is a photographic recording of a light field, rather than of an image formed by a lens, and it is used to display a fully three-dimensional image of the holographed subject, which is seen without the aid of special glasses or other intermediate optics. The hologram itself is not an image and it is usually unintelligible when viewed by diffuse ambient light. It is an encoding of the light field as an interference pattern of seemingly random variations in the opacity, density, or surface profile of the photographic medium. When suitably lit, the interference pattern diffracts the light into a reproduction of the original light field and the objects that were in it appear to still be there, exhibiting visual depth cues such as parallax and perspective that change realistically with any change in the relative position of the observer.



In its pure form, holography requires the use of laser light for illuminating the subject and for viewing the finished hologram. In a side-by-side comparison under optimal conditions, a holographic image is visually indistinguishable from the actual subject, if the hologram and the subject are lit just as they were at the time of recording. A microscopic level of detail throughout the recorded volume of space can be reproduced. In common practice, however, major image quality compromises are made to eliminate the need for laser illumination when viewing the hologram, and sometimes, to the extent possible, also when making it. Holographic portraiture often resorts to a non-holographic intermediate imaging procedure, to avoid the hazardous high-powered pulsed lasers otherwise needed to optically "freeze" living subjects as perfectly as the extremely motion-intolerant holographic recording process requires. Holograms can now also be entirely computer-generated and show objects or scenes that never existed.



Holography should not be confused with lenticular and other earlier autostereoscopic 3D display technologies, which can produce superficially similar results but are based on conventional lens imaging. Stage illusions such as Pepper's Ghost and other unusual, baffling, or seemingly magical images are also often carelessly called holograms.

Answer 7

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. Some holograms even appear to move as you walk past them and look at them from different angles. Others change colors or include views of completely different objects, depending on how you look at them.



Holograms have other surprising traits as well. If you cut one in half, each half contains whole views of the entire holographic image. The same is true if you cut out a small piece -­- even a tiny fragment will still contain the whole picture. On top of that, if you make a hologram of a magnifying glass, the holographic version will magnify the other objects in the hologram, just like a real one.

Answer 8

A conventional video capture two things: color and motion. It maps colors that stay constant until motion, and then it tracks the motion and remaps the colors. This happens thousands of times a second, and gets very hefty on the hard drive space, especially when there is no motion involved and backgrounds are random. When you are watching a youtube video and it suddenly drops in quality after some sort of random transition or intentional static, that is because the motion gets hectic and the compiled video has problems conveying itself.



However this becomes a huge problem when holograms are involved, and in my opinion they are entirely inefficient in every way. Lets take for example Princess Leia's hologram message to Obi-Wan Kenobi. She took up about 20 visible pixels by 70, which I'm going to change to 24x64 because computers store things in multiples of 8. Because the hologram uses 3 colors, black white and grey, each pixel is 3 bites. Again, this is a pain, but rounding that is more of a pain so I'm calling it 3. So in the picture version you have 24 pixels wide by 64 pixels tall, times 3 colors per pixel, for 4,608 bytes of code. Not a whole lot. But for 3d images, you add depth, which is in this case 24 pixels, and this comes out to 110,592 bytes, which is a ton of storage. Not to mention the fact that this is the most simple type, with 3 colors.



When you want a full color hologram in a 64 pixel cube, it is about 4.398047 x10^12 bytes, as opposed to the normal 6.8719 x10^10. This may not seem like a huge difference, but when you have a ten second loop of that plus sound it becomes a huge storage eater.

Answer 9

Alright, it seems as though the scientific explanations are getting more thumbs down, than thumbs up. The multicolor, grainy, raster image of the holograms in Star Wars suggest some kind of projection trick like a couple of the arcade games of the early eighties that used concave mirrors and curved Fresnel lenses to produce hologram-ish 3-D effects. The true hologram is more like a kind of negative exposed on a super fine-grained black and white photographic plate. To produce, it requires a coherent laser light, and a beam splitter. If I remember correctly, half the beam has to go through the photographic plate from front to back, close to where the observers eye would be, and the other half has to go around behind the plate, and bounce off the object to reflect onto the backside of the plate. Since the plate is clear glass (or plastic) the light coming from both sides meets in the surface of the the emulsion, and that's where the wave fronts show up on the film. Where the wave fronts add up, that makes a dark spot on the negative, where they cancel out, they don't expose the plate and a clear area is left. Of course all of this happens on a microscopic scale, but it looks like a repeating Jackson Pollock under a powerful microscope. TRY THIS at home: Shine a red laser pointer through a silkscreen, or any very fine synthetic even-weave fabric. you should see a square-grid cluster of laser dots on the wall. That's not because the laser light is shining through the holes the way a pen-light would shine through a wicker chair, rather the spacing of the pattern is independent of how far away the laser is from the screen. If you use an old VGA screen from a smashed monitor, you'll get a hexagonal grid. I think we'll see something more like the holodeck in Star Trek (light only, no touch for a while) by tiling flatscreens with holographic capabilities on the walls of a room. Now, about those holographic capabilities, the real trick to 3-D is to make a slightly different image for every tiny arcsecond of angle of observation. Your two eyes see two slightly different versions of the image and your brain puts it back together again. You need to produce some kind of interference wave front, maybe a laser diode behind every pixel, with something like a little ultra-high resolution LCD screen in fron of every laser pixel. (Try 25nm black pixels) Or maybe you could just produce a phased array of visible light slot antennas, with light squirting out of the slits. Making a holographic figure stand out in the the open without some kind of screen behind it is a different matter. Maybe within a room, you could project an interference pattern on the walls and furniture.

TRY THIS: using a green laser pointer, in a darkened room, strap down the "ON button" with a zip-tie (temporarily) and aim it up at the ceiling, and put it in a coffee cup so that it holds still. Now observe the speckled light that shines back down into the room. It's better observed on a sheet of typing paper or white posterboard. I think what you're seeing is the raw interference of the different wave fronts caused by all the different levels of the particles of paint in the ceiling. If you move the posterboard toward and away from the spot projected on the ceiling, you'll notice that the pattern doesn't change, it only gets larger the farther you move away. This interference pattern is similar to the speckles on the holographic plate. Even an LCD or LED-backed flatscreen produces some rainbow repeating patterns around the reflection of a lightbulb. In order to get the free-floating hologram like princess Lea, the best route might be a swarm of luminescent nanobots like a cloud of lightning bugs.

PICTURE #1:(aluminum foil rough, dull side)

Answer 10

­If you want to see a hologram, you don't have to look much farther than your wallet. Th­ere are holograms on most driver's licenses, ID cards and credit cards. If you're not old enough to drive or use credit, you can still find holograms around your home. They're part of CD, DVD and software packaging, as well as just about everything sold as "official merchandise."



­Unfortunately, these holograms -- which exist to make forgery more difficult -- aren't very impressive. You can see changes in colors and shapes when you move them back and forth, but they usually just look like sparkly pictures or smears of color. Even the mass-produced holograms that feature movie and comic book heroes can look more like green photographs than amazing 3-D images.



­On the other hand, large-scale holograms, illuminated with lasers or displayed in a darkened room with carefully directed lighting, are incredible. They're two-dimensional surfaces that show absolutely precise, three-dimensional images of real objects. You don't even have to wear special glasses or look through a View-Master to see the images in 3-D.



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. Some holograms even appear to move as you walk past them and look at them from different angles. Others change colors or include views of completely different objects, depending on how you look at them.



Holograms have other surprising traits as well. If you cut one in half, each half contains whole views of the entire holographic image. The same is true if you cut out a small piece -­- even a tiny fragment will still contain the whole picture. On top of that, if you make a hologram of a magnifying glass, the holographic version will magnify the other objects in the hologram, just like a real one.



Once you know the principles behind holograms, understanding how they can do all this is easy. This article will explain how a hologram, light and your brain work together make clear, 3-D images. All of a hologram's properties come directly from the process used to create it, so we'll start with an overview of what it takes to make one.

Answer 11

A hologram's a lot like a photo, except it never fades or degrades. Holograms are everywhere; on stickers, jewelry, money, art and credit cards. What's so fascinating is that, at first glance, the hologram looks like a flat photo. But when you tilt it a certain way something seems to move inside the photo (or picture.) For example, some credit cards have the image of a bird inside and when you tilt the card just the right way, the bird will look like it's flying inside the picture. Almost like there's an apparition inside a flat picture. Another good example is a hologram sticker that may look like a smiley face, but when you tilt it, it may have a sad face inside. The best way to describe holograms is to say that they look like they've trapped some other image inside.

So, you must be wondering how and what makes that bird fly and that face change expression?



We have to understand how a camera sees things, how our eyes see things and, finally, how a laser makes things appear. So here we go:



A camera's lens can only shoot a picture in two dimensions. So if you're taking a photo of a dog, the light that travels from the dog into the lens of the camera or chip is coming from only one direction and into one single lens. That's why the camera can only "see" two dimensions, regardless of colors or patterns. It "sees simply."



But, if your eyes are looking at the dog, it's a totally different situation. Again, the light reflects from the dog into your two eyes as two different pictures that your brain combines into one image - that's three dimensional. Our eyes see three dimensions. The camera lens sees two.



Now what if you're looking at the dog, but then you move your head. Then those rays of light reflecting off the dog have to move along a slightly different path to reach your eyes and that's when the dog may look darker or lighter or even a different color. Your brain's amazing and can rethink everything to help you see a different three dimensional image.



So why did I tell you all this extra stuff? Because now you'll get my explanation of how a hologram works!!



A hologram is a combination of what happens with a photo and what happens when you "see." Remember we said a hologram is permanent Both the photo and the hologram keep a permanent record of what you saw, just differently. Only the hologram looks real and three-dimensional and moves as you look at it - just like a real bird or a real dog. That's what makes holograms so different.



Holograms need lasers. The light waves in a laser all travel exactly in a straight line, right to the point. When you split up that laser beam to make the hologram the light waves continue traveling the same course, but there are now two of them. When they reach the "plate" (that's the photo) the one beam has just slightly taken a different path. This is the easy part - By joining the two beams back together, you can see how the object changes its light, creating what the hologram "looks like." The info is now permanetly burned into the plate. SO THE HOLOGRAM BECOMES A PERMANENT RECORD OF WHAT SOMETHING LOOKS LIKE FROM ANY ANGLE. As you move your head around, the hologram appears to be changing, just as a real object would. THIS IS WHY HOLOGRAMS APPEAR THREE-DIMENSIONAL.

Answer 12

A hologram is essentially a three-dimesional photograph. However, it takes much more work to make a hologram than it does for an ordinary two-dimensional photograph. To learn how holograms are made, we first need to learn a little about lasers.



Interference is what holograms are all about. A hologram is basically a reproduction of the "interference pattern" of laser light that's been shined on something. Let's say we had a coffee cup and we shone some laser light on it. However, we didn't shine all of the light on the cup. Some we diverted directly onto the photographic paper (the reference beam). The rest of the laser light (the object beam) shines on the cup, and is then reflected onto the paper. So we have light straight from the laser source and light that's been reflected from the cup. These two beams interfere with each other, causing a specific pattern of bright and dark spots where there has been constructive and destructive interference, spots where the waves added and subtracted.





It's the interference pattern that the photographic film records, unlike a regular photograph, which records the amount of light from a specific point (see the module on pinhole cameras for more information). Also, unlike the photograph, each point of the hologram contains all of the information from the object. So we could destroy almost all of our hologram and still reconstruct the image from a small piece. Try to do that with your regular photograph!



To see the hologram, we have to shine light that's just like the reference beam onto the photographic film after it's been developed. To see the hologram made from a laser, we need to use a similar laser. Now do you see why it's so hard to duplicate a hologram?!

Answer 13

Holograms are those shiny and metallic patterns with vaporous description floating inside them that help to defeat counterfeiters: they're very hard to reproduce so they help to stop people printing illegal copy, hologram seals to prove their authenticity. What else can you use holograms for? Let's take a closer look at what they are and how they're made in history their producing goods to care security.

Answer 14

A hologram is a light projected onto something like glass or a screen. For a hologram to work, the light has to hit something before it stops moving. For example: If you shine a flashlight, the beam of light goes until something stops it. A hologram has to have something to shine on to be seen, otherwise the light pretty much runs away.

Answer 15

I can't even begin to understand what people before me have written. Holy moly. You can't begin to understand how holograms work until you understand how the eyes and the brain work. My advice is, don't even ask how Holograms work. If you want my answer, here it is: There are multiple types of holograms. The ones embedded in your credit card, and the ones depicted in Star Wars with Obiwankenobe. They are all optical tricks. That's it.

Answer 16

Holography is the science and practice of making holograms. Normally, a hologram is a photographic recording of a light field, rather than of an image formed by a lens, and it is used to display a fully three-dimensional image of the holographed subject, which is seen without the aid of special glasses or other intermediate optics. The hologram itself is not an image and it is usually unintelligible when viewed by diffuse ambient light. It is an encoding of the light field as an interference pattern of seemingly random variations in the opacity, density, or surface profile of the photographic medium. When suitably lit, the interference pattern diffracts the light into a reproduction of the original light field and the objects that were in it appear to still be there, exhibiting visual depth cues such as parallax and perspective that change realistically with any change in the relative position of the observer.

In its pure form, holography requires the use of laser light for illuminating the subject and for viewing the finished hologram. In a side-by-side comparison under optimal conditions, a holographic image is visually indistinguishable from the actual subject, if the hologram and the subject are lit just as they were at the time of recording. A microscopic level of detail throughout the recorded volume of space can be reproduced. In common practice, however, major image quality compromises are made to eliminate the need for laser illumination when viewing the hologram, and sometimes, to the extent possible, also when making it. Holographic portraiture often resorts to a non-holographic intermediate imaging procedure, to avoid the hazardous high-powered pulsed lasers otherwise needed to optically "freeze" living subjects as perfectly as the extremely motion-intolerant holographic recording process requires. Holograms can now also be entirely computer-generated and show objects or scenes that never existed.

Holography should not be confused with lenticular and other earlier autostereoscopic 3D display technologies, which can produce superficially similar results but are based on conventional lens imaging. Stage illusions such as Pepper's Ghost and other unusual, baffling, or seemingly magical images are also often carelessly called holograms.

Answer 17

That would be the Hollywood "tech world" you have in mind, ie fiction. There is no such thing as a real R2D2 holograms. The closest thing today are 3D movies and TVs that use two images polarised at 90 degrees or time division gated. There is also a spinning angled projection screen surface, etc.

A real hologram is a mono-color film that carries tiny lines too small for you to see. Those lines create a diffraction grating that interferes with a specific wavelength/color of light and that interference forms an image that appears to move as your point of view moves. The lines are created by exposing the undeveloped film to the same wavelength light that has come by two paths, direct and from the object being photographed. Where those two light sources are out of phase, you get a black line. So called holograms used in money ( in more advanced countries) and stickers carry their own color filters to work with the hologram.

Answer 18

A simple Hologram can be made from several photographs of an object taken at different angles and then reproduced on a sheet of material that has ridges, each photo is printed onto a specific ridge face so that only one photograph is visible at any one angle,

You can create a hologram using a scanning laser, coherent light (light from a laser) is split in two with a prism, one beam that stays undisturbed and is called the 'reference beam', this directly strikes a photographic plate, the second beam is called the object beam, this strikes the object and then bounces onto the plate. the object interfering with the second beam causes the light from the second beam to hit the plate slightly later than the first beam, the difference is called phase interference. The result on the plate is a holographic image.

Answer 19

PLEASE, let us change our names and avatars again soon.



A hologram is a physical structure that diffracts light into an image. The term ‘hologram’ can refer to both the encoded material and the resulting image.



A holographic image can be seen by looking into an illuminated holographic print or by shining a laser through a hologram and projecting the image onto a screen.



Holography is based on the principle of interference. A hologram captures the interference pattern between two or more beams of coherent light (i.e. laser light). One beam is shone directly on the recording medium and acts as a reference to the light scattered from the illuminated scene.

Answer 20

Holography is the science and practice of making holograms. Normally, a hologram is a photographic recording of a light field, rather than of an image formed by a lens, and it is used to display a fully three-dimensional image of the holographed subject, which is seen without the aid of special glasses or other intermediate optics. The hologram itself is not an image and it is usually unintelligible when viewed by diffuse ambient light. It is an encoding of the light field as aninterference pattern of seemingly random variations in the opacity, density, or surface profile of the photographic medium. When suitably lit, the interference patterndiffracts the light into a reproduction of the original light field and the objects that were in it appear to still be there, exhibiting visual depth cues such as parallax andperspective that change realistically with any change in the relative position of the observer.

Answer 21

Really don't see how it's possible without having objects for the lights to shine on, since light is continuous, it doesn't just stop at a distance . So, I think having two lights positioned at opposite direction crossing each other at a designated elevation would be the way to go. To give you a better idea, it would be arranged as tiny spotlights all coming from a single rail, thousands of tiny spotlights that would equal double the amount of the desired pixel resolution. The right side half of the rail would have the lights pointing straight to the north west while the left-side half would point straight to the north-east. When a right side beam crosses with a left side beam, the crossing section will be the pixel, in the shape of a diamond.

Answer 22

Since 5 people here have already explained holograms better than I can, I'll just add some extra info which I hope may be helpful.

HoloGRAMS require the use of lasers to produce them, and sometimes also to view them.

HologGRAPHS on the other hand, only need normal visible light, and can be made with just mirrors. Typically, two parabolic mirrors – similar to what you find in car headlights – will be cupped together to form a spherical container.

Inside, at the bottom and on the centre, the object to be viewed will be placed. On the centre of the top mirror, a sufficiently large hole will be cut out, through which to view the object.

Then, due to the properties of parabolas and the remarkable and handy way in which parabolic mirrors reflect light, when you look into that hole at the top, it appears as though the object is actually there, at the hole, instead of deep down inside where it really is.

Strathclyde University had one such display in the 5th floor entrance to their Physics HQ in the John Anderson building. You would see a can of Irn Bru, but when you reached in to grasp it, it would vanish as your hand “moved through” it!

I’ve since also seen many toys based on this principle, on sale in shops.

As for HOLOGRAMS – the best example I know of a practical use of this is in the Head-Up Displays (HUDs) of some fighter planes. It has the advantage of allowing the pilot to both view any potential adversary – and the world in general – and also the instrumental info from his craft, without having to waste precious time moving his eyes between the two and having to refocus his eyes.

I believe this application is now being adapted by some car manufacturers too.

Otherwise, this story is misleading! Just like the other advertised feature "Tell us what you really think about Yahoo", when it's not about that at all! It's all typical Yahoo! sensationalism.

This is just about some fancy new 3D goggle-type apparatus, like Virtual Reality, and not the same as R2D2-style holograms at all!

Yahoo! are just perpetuating a myth, also perpetuated by all those "procedural police dramas" from the US, like CSI, Bones, NCIS, etc., where the forensic folk sometimes use technology which doesn't actually exist yet!

Answer 23

"hologram" has two meanings. There is the precise scientific definition - this involves creating a true 3D image using lasers and interference patterns. "Hologram" is also a vague blanket term loosely used by the general public to describe any kind of 3D-looking effect that they don't understand and don't otherwise know what to call.



Still image true holograms have been around for decades. However true video holograms in the scientific sense, is a technology that really doesn't exist yet. According to the last thing I saw on it, the best we could do is low resolution, single colour objects inside a box, and that can only be viewed by two people at a time.



There are all kinds of other technologies (not true holograms) that can create hologram-ish effects in various ways and to various degrees of success. These range in sophistication from a piece of clear plastic used to create a Pepper's Ghost illusion, to expensive medical imaging technology (a company in Israel seems to be on the leading edge, although their marketing video uses a bunch of misleading special effects to make it look much more impressive than it really is).



There is nothing though that comes close to R2D2-style projecting 3D images into mid-air like we saw in Star Wars. I'm not even aware of any known physics that would theoretically allow such a thing, and I seriously doubt anybody today will live to see anything like that. I believe the best we've got right now is projecting blurry 3Dish-looking 2D images onto a screen made of mist.

Answer 24

I saw alot of very complicated answers, so I'm just going to shorten that and say that holograms are special reflected light that collects in the air, so your mind interprets it as a picture.

Answer 25

It work by projecting an image into the air and stopping it at specific range so i creates a 3D image (Which is almost impossible since you can't stop moving light, unless you are using synthetic fog that can be shaped as medium.) Or by projecting an or video( image or video must be flipped from left to right or it will looks like mirrored image) onto glass that is placed 50 degrees horizontally from the light source

Answer 26

One has to know that light interferes with itself. Just like sound waves. Or water waves, for that matter. When two waves interfere, there is a pattern that develops: the resulting wave will be twice as high here (both waves add-up) and be cancelling one another there.

Now, suppose that we could freeze the water waves as they interfere. We'd then have a pattern. In the case of light, that "frozen"pattern is the hologram frame, it essentially records how the light was interfering with itself when it was reflecting off the object being holographied. Basically, the interference pattern -- how each light beam wave cancel here and not there -- is like a frozen aspect of how light appears at different places on a plane between the observer and the object, so it is all the possible perspective aspects which vary along that plane, so in essence, a holographic plate records all the various point of views.

The neat trick is that if we now shine a light with the right characteristics (same frequency) as was used to make the hologram in the first place, the little patterns on the holographic plate will force the light into the same interference pattern as existed when the plate was made; looking though the plate we would then see light as if it came off the object. And since your eyes have a slightly different perspective and are therefore looking at a different portion of the hologram, you basically see the object as if it was there.

Answer 27

Holography is based on the principle of interference (an overall pattern that results when two or more waves interfere with each other, generally showing regions of constructive and destructive interference). A hologram captures the interference pattern between two or more beams of coherent light (ex. laser light). One beam is shone directly on the recording medium (a device that only holds information) and acts as a reference to the light scattered from the illuminated (artificial light) scene :)

Answer 28

Holograms are like basically 3D projections of an image

Answer 29

Basically it works like the inside of the human eye, light is turned upside down and the image is interpreted by the brain, in a hologram the light is trickily reflected to give the representation that glows and is seen (in the case of the case you've cited) as a 3D picture, will there be moving pictures and talkies, and will we complain if they don't synic?

Answer 30

hai hologram is a record of the summated phase of light ART THAT POINT most simply cancel the result is the record of what remaining , on re-illimintion the phase at that point is distributed over the sceen - in effect 'drawing ' another hologram - perceived as the original image



what is seen on star wars is Peppers Ghost - rotating miroor - which the sound of it rotating , sound is dubbed in later - standard .be all soughts of unwanted noises otherwise

Answer 31

Holography is based on the principle of interference. A hologram captures the interference pattern between two or more beams of coherent light (i.e. laser light). One beam is shone directly on the recording medium and acts as a reference to the light scattered from the illuminated scene.

Answer 32

A hologram is essentially a three-dimensional photograph. However, it takes much more work to make a hologram than it does for an ordinary two-dimensional photograph. In order to make a hologram, we need to use lasers which produce coherent light; that is, light whose waves are in phase, peak-to-peak and trough-to-trough. The property of coherence allows laser light to interfere with itself quite nicely and produce interference patterns on paper that we can reproduce. A hologram is basically a reproduction of the "interference pattern" of laser light that's been shined on something. Let's say we had a coffee cup and we shone some laser light on it. However, we didn't shine all of the light on the cup. Some we diverted directly onto the photographic paper (the reference beam). The rest of the laser light (the object beam) shines on the cup, and is then reflected onto the paper. These two beams interfere with each other, causing a specific pattern of bright and dark spots where there has been constructive and destructive interference, spots where the waves added and subtracted.

Answer 33

Okay, do you think the poor guy will understand your long-complicated answer. Bro, you just need to know that it's light power/energy, which makes that 3D dimension hologram.

Answer 34

I could give a completed answer, because it really is quite completed. Instead I'll tell you how to make one at home with little effort. A piece of cardboard with a shape of your choice cut out in the middle. A few laser pointers, and a source of smoke. Keep the laser pointers moving very quickly behind the cardboard. Aim the lasers at the smoke through your shape.

Answer 35

A hologram is essentially a three-dimensional photograph. However, it takes much more work to make a hologram than it does for an ordinary two-dimensional photograph. In order to make a hologram, we need to use lasers which produce coherent light; that is, light whose waves are in phase, peak-to-peak and trough-to-trough. The property of coherence allows laser light to interfere with itself quite nicely and produce interference patterns on paper that we can reproduce. A hologram is basically a reproduction of the "interference pattern" of laser light that's been shined on something. Let's say we had a coffee cup and we shone some laser light on it. However, we didn't shine all of the light on the cup. Some we diverted directly onto the photographic paper (the reference beam). The rest of the laser light (the object beam) shines on the cup, and is then reflected onto the paper. These two beams interfere with each other, causing a specific pattern of bright and dark spots where there has been constructive and destructive interference, spots where the waves added and subtracted.

Answer 36

I don't know what a hologram is so how could I know how to explain it??? Well... these people have given really hardcore answers... good for them!



#Explainthis: The future of tech!

Answer 37

how many explanations do we have to have for this question?

It has been up for several weeks, many kind and bright intellectually astute

'people have presented compelling descriptions in answer to this question. Bravo for them.

Now it is time for us bright ones to move on to other challenges. What do you all think we need to know answers to next? Congrats to all the wonderful people who took the time to teach the rest of us things we wouldn't look up (or understood even if we did!) You all are brilliant. I thank you very much. I love holographic techniques, but don't want them in my home..

Answer 38

If the tech world has taught us anything recently, it’s that very soon we’ll all have R2D2-style Holograms appearing all over our house. And we want that very much.



Except we’re not quite sure how they work. So we’re asking you..

Answer 39

Now I am no scientist, but I like to imagine so I will give my input. I like to think that since light is an electromagnetic wave you can manipulate it. So if there were a way to record it in three dimensions, and have it specifically record the frequencies of light and be able to create a way with I guess would be tiny magnets moving around to create say a magnetic field that could form the person speaking in the recording and move ever so slightly to simulate them talking it could work. I WANT TO MAKE CLEAR THAT I AM NOT A SCIENTIST

Answer 40

Holography is based on the principle of interference. A hologram captures the interference pattern between two or more beams of coherent light (i.e. laser light). One beam is shone directly on the recording medium and acts as a reference to the light scattered from the illuminated scene.

moreover: http://holocenter.org/what-is-holography (for more curiousity)

youtube : www.youtube.com/watch?v=uCx1ntBsJqE or

wikippedia: https://en.wikipedia.org/wiki/Holography

Answer 41

A hologram uses a screen. There are two types...type 1 forms an image between the observer and the screen, and type 2 forms an image behind the screen.



In type 1, if the observer moves so that the object (R2D2?) is not between the observer and the screen, he (it) will disappear.



In type 2, the image forms behind the screen, and the observer seems to be looking through a window at it. If the observer moves so that R2D2 is not visible through the window, he will disappear and new objects will appear.



For holographic images to appear all over the house, all the walls would have to be holographic screens.

Answer 42

Insert a bionic chip into your neck that gives you powers. One of them may be the power to create holograms.

Answer 43

hologram is question for process replication request for purpose code

Answer 44

There is currently no known way to produce a free floating 3D image as seen in science fiction movies.

Answer 45

I think they could work like movie projection. But I HOPE that R2-D2

Holograms will come out soon!!!

Answer 46

yahoo is one of the greatest think we have . we all must try to influents and commit our self to teach our young children's through our experiences ,and prepare theme for the hard coming years ahead .to Meany misfortune children's born by wedlock

I am a very bad speller and today through the yahoo answers, I clamed for my self with grater ability to wright and spell much better now. this is a good example. projecting our values to a young person is our

dudes we hived destroyed our children's we make them believe the wrong things. we have to teach them the societies and people are not the same. is deferens coachers ethnic and quality of people, avoid mix marriages tin pregnancy's and make changes in schools to prevent all this. we falling the 23 in education. and the social dizzies are 70% on schools . all this are unacceptable.

Answer 47

Guaranteed Ex Back StepByStep Guide - http://ExBack.GoNaturallyCured.com

Answer 48

NO NO NO not everyone wants that artificial junk .Most might want that technology. though it has helped in many ways its also hurt us at the rate were going were going to technologically advance our asses right off the face the face of the earth we are already on course for that

Answer 49

Traditional holograms work like the two-slit experiment. If you shine light through two slits, you get an interference pattern on a screen. That's reversible - if you make a model of the interference pattern ,and shine light through it, you get an image of two slits on the screen. Same as transforming from the frequency domain to the time domain with sound waves - the frequency picture showing high and low notes to the wave picture showing the sound decaying away.

So if you shine light on a rubber duck and record the wave pattern produced, you can shine light on that pattern and get a rubber duck back. Or at least, a 3D image of one. It works best with lasers.

Answer 50

I do not want R2D2 style holograms appearing "all over my house." I will be finding out really quick how they work so I can prevent this abortion from happening.

Answer 51

Hollow, is empty, gram often is used in reference to communication. Ever see smoke in the slit of ray of sun?

Maybe through a window. You can project an image in smoke or move it... then there is the aspect of looking

3D... so as far as the future... I assume.... lol, it is the way we will be presenting ourselves in 3D communication...

Will be fun to watch folks walk down the street w/their cell phones and a ghostly like figure beside them and

everyone else... who needs the real folks... oh yeh, touch is nice... j

Answer 52

I don't know but I have an R2D2 cooler for sale

Answer 53

Basically with some deep dark magic. But you need the approval of your Coven first.

Answer 54

By bending light

Answer 55

A HOLOGRAM WORKS WHEN SUNLIGHT RETRACTS ON ITS HOLOGRAPHIC IMAGE MAKING IT APPEAR SOMEWHAT TRANSLUCENT AND SOMEWHAT THREE-DIMENSIONAL!!!

Answer 56

they DONT work, its all illusion to the eye, you CANNOT control light, for now.... so having a 3D image in just air is impossible, all the 3D glass stuff and imagery is simply manipulation of the eyes and brain.

Answer 57

Like Louis Armstrong said when somebody asked him to explain jazz, Satchmo said " If it has to be explained to you, you won't understand it anyway!

Answer 58

You only need one plane to make it work

Answer 59

is a physical image that reflect light directly to a particular thing that is faceting it

Answer 60

How they work? A bunch of atoms come together

Answer 61

Probably just magician blessed tin foil

Answer 62

It s a 3D picture,That reflect the light differently from different sides,so we see different pictures from different sides.

Answer 63

They have great holograms at Disneyland, have had them for years, it is just layers of light that make a 3d image that looks like a real ghost or talking doorknob or whatever.

Answer 64

Just google it if you need to know. It would be so much simpler than us trying to cut and paste the answer.

Answer 65

a three-dimensional image formed by the interference of light beams from a laser or other coherent light source.

Answer 66

theres a whole universe inside each atom.

Answer 67

Light, smoke & mirrors.

Answer 68

you tap a switch and the person of which is making the hologramto you pops up as a 3d character.

Answer 69

hologram (n): a message that contains nothing.

Answer 70

Don't know, never employed one, but when I do, I'll let you know.....deal?

Answer 71

You need to know allot about computers and graphics to be able to answer this, I believe.

Answer 72

its some next level stuff

Answer 73

This is slightly ahead of its time, in due time, we'll find out. I do believe.

Answer 74

I mean.....Star Wars could do it......why can't you?

Answer 75

I think "the tech world" has taught us a lot more things recently than just that. In fact, I don't think it has taught us that at all.

Answer 76

how can i make xp bootabile cd

Answer 77

it projects on the screen from pc

Answer 78

How about holokilo gram?

Answer 79

lasers

Answer 80

they just do

Answer 81

SCIENCE!

Answer 82

i dont know :P

Answer 83

idk