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Holographic Display

Full-Color Holodeck-Type Thinger
  [vote for,

Take a clear tube, fill it with three noble gases (they at least must be non-reactive with each other and the tube material), one for red, one for green, and one for blue. Each must respond to a laser wavelength with that particular color.

Then, take three lasers: one red, one green, one blue (low power lasers may be enough), split each beam holographic-style, and fire one beam of each straight into the tube (a diffuser or lens may be required to make it even throughout the length and width of the tube). The other half of each beam sets up interference patterns according to the information it gets from the data source (computer with super-duper 3D card, live holographic camera using the same technique, etc.).

Voila! The interference patterns show up as a moving (or still) 3D picture!

galukalock, Feb 23 2003

Current Projection Techniques http://www.laser-ma...phicprojection.html
This idea is similar to TransScreen Transparent Projection. [reap, Oct 04 2004, last modified Oct 05 2004]

The real thing, almost http://www.leary.co.../Technology/3D.html
Different materials, same idea. [galukalock, Oct 04 2004, last modified Oct 05 2004]

3d display cube http://www.engadget...he-3d-display-cube/
[Dub, Feb 27 2006]

(?) 3D plasma in thin air http://www.newscien...ch-tech/dn8778.html
"The night sky could soon be lit up with gigantic three-dimensional adverts, thanks to a Japanese laser display that creates glowing images in thin air." [gtoal, Feb 27 2006]


       The red and blue glasses give me a headache.   

       It's not so much what's wrong with current 3D stuff as what it *doesn't* do. It doesn't allow for true 3D videoconferencing (a meta-use in itself), true 3D presence (as a teacher could be teaching many classes at once, or a professor could give a 3D lecture at many universities at once), or true 3D recordings (remember how R2-D2 played back Luke Skywalker's message for Jabba?). There are probably more, but I can't think of any right now.   

       The main purpose is to make possible in 3 dimensions what is already done in 2 (TV, for example).   

       As for understanding the technology, you might want to read about the mechanics of existing holographics before fishboning nonexistant ones. Incidentally, what part is it you don't understand? I'll be happy to explain it further to you.
galukalock, Feb 23 2003

       I like it, but how do you keep the entire lines of the laser from showing up? For instance, if I want one dot in the center.
Worldgineer, Feb 23 2003

       I'm not sure if this will work *at all*, but that aside, it works by setting up interference patterns, kind of like amplified light (but different), which should be much brighter than the (necessary) ambient light from the other half of each beam.
galukalock, Feb 24 2003

       Baked. Fishbone.
ironfroggy, Feb 24 2003

       Link. Proof. Civility.
Monkfish, Feb 24 2003

       // what's wrong with current 3-D technology? //   

       Hardly a fair halfbakery question, methinks. What's wrong with our current clock?
RayfordSteele, Feb 24 2003


       1. What is current 3D technology?   

       It is really the *illusion* of 3D projected onto a 2D screen. It also is not very detailed, although with the advent of the GeForce3 and 4, and Radeon 9700, it's getting close.   

       2. Given that, is it (current 3D) suitable for 'virtual presence' in 3D?   

       No, the processing power of most computers is not yet enough to handle such a complex set of images (which would have to be much more complex than in the most complex games to be photo-realistic, while this technology would be photo-realistic); and even then, the person would have to be in a motion-capture suit, surrounded by dozens of cameras and lights, and would not be able to move further than the set.   

       3. Why is this technology any better?   

       It requires no special suit, no special glasses, only a special camera and 'TV'.   

       It is photo-realistic.   

       Its images can be sent as radio waves, then converted, as with regular TV, making it much simpler than trying to virtual-conference over the Net.   

       Also, being photo-realistic, it makes virtual-conferencing *much* better, as you can see the person full-size, from all angles, in true 3D (now imagine virtual-conferencing with a VR set on, looking at essentially a 3D stick-figure. Like it?). It is as though s/he is actually there, but s/he doesn't have to spend all that time, jet fuel, and money to meet you.   

       [Rayford], since there is so much "wrong" with current 3D, I guess it was okay.   

       Thanks, [Monkfish].   

       I bet [ironfroggy]'s the autoboner. Let's see a link.
galukalock, Feb 24 2003

       Before I can add a croissant, I still need to understand the technology. If laser light fills the tube from one beam, how do you illuminate only one point with the other? And don't just say "interference pattern" without explanation, I don't buy it. Perhaps if both streams were controlled it could work.
Worldgineer, Feb 24 2003

       2D holography works thusly:   

       Take a laser beam, split it by means of a prizm or half-mirror. Aim one half directly at some aluminum-type stuff (which records the image). Aim the other half at the object to be holographed. Rotate the object and the 'film' ~45 degrees in each direction, in unison, to produce the 3D image on the 'film'. The two halves of the beam interfere with each other, etching their interference patterns into the 'film', which you see as a (not necessarily high-quality) 3D still image. That's about as well as I can explain it. I'll try to find a link.   

       This approach replaces the film with gases, which are not permanently etched, but fluoresce from the interference between the beams. It also uses 3 lasers instead of one to allow full color (traditional holography is monochrome). And because the gases are not permanently etched, this device would allow for moving holography, not just still pictures.   

       Anyway, the gases only fluoresce (producing a dot) where the beams interfere with each other. That's why you don't see a line.
galukalock, Feb 24 2003

       But isn't traditional holography done on a 2-d surface? I don't see what's different in your second beam at one point (say 1" into the tube) vs. another (2" into the tube). How does the second beam of the laser interfere with all points in the tube except the point it needs to floress(sp?)?
Worldgineer, Feb 24 2003

       Even with a "super-duper 3D card", the image would still be 2 dimensional. You are using 3 lasers to achieve 3 colours, and a single image at any point in time. You would need an array of these working simultaneously in order to achieve the sides and back of the image. Even then, they would be all muddled together. By projecting through a gas, the image would be visible from both sides.   

       Say you are projecting a face. The face would be visible from the front and the back (unless your interference patterns are now opaque) but not the sides. From the sides, all you would see is a very skewed facial image.   

       [link] for example of current holographic techniques. Including TransScreen Transparent Projection which is essentially the same sort of technique.   

       Your technique would still be the *illusion* of 3D, rather than true 3d.
reap, Feb 24 2003

       [Worldgineer], yes, traditional holography is done on a 2D surface, and the *illusion* of 3D recorded on it. As for how the laser manages not to interfere all over the place, I don't know. (Lens maybe?) As I said before, I'm not sure if it would work at all. But I do know a bit about holography, and I got this idea to extrapolate it to 3 dimensions. Room for improvement? Plenty.   

       [reap], you are right except for the last sentence.   

       What this would produce is a hollow 3D object, perfectly viewable from the front and maybe 45 degrees to each side, depending on the camera or data source. If you had a super 3D card, it could produce a 3-dimensional face, but looking at it from the back, you would see the back of the head. If it was a person's face in front of a holo-camera, you'd see their face and some of the sides of their head (depending on the maximum angular range of the camera), but looking at them from the back, you'd see a completely inverted version of the face not unlike the inside of a mask.   

       So yes it would be 3D, but no, not viewable from the back or very far to the sides except for computer-generated 360-degree shapes.
galukalock, Feb 24 2003

       Big update: latest link shows technology similar to this, and it WORKS! Bad news is, that means it's already half- or more baked.
galukalock, Mar 18 2003

       No, yours is different. Theirs is basically creating many 2-d images on panes of glass stacked together, forming a 3-d image. Theirs has a maximum resolution limited to the thickness of each pane of glass. Yours has resolution down to the atomic scale. Of course, I still don't know how yours would work.
Worldgineer, Mar 19 2003

       Mine would work using the exact same principles as theirs (lighting up only where beams intersect), but requires different materials in order to be gaseous, or merely gasify the same materials. It looks as though it'd need more than one laser of each kind, though. Also, it may be that it should use IR lasers, as theirs does.
galukalock, Mar 20 2003

       there is something that doesn't fit here :-) mainly the "red" laser to say so ... i don't think you could find a gas to "fluoresce" as a result of being hit by a red lasr light ... not to mention a low power laser   

       you know ... any tipe of matter fluoresces acording to the frequency of the ray that "hits" it ... and they all have a certain energy called ionization energy at witch they get ionized and as a result they exhibit fluorescence in the form of light   

       well ... in order to actualy make a gas fluoresce and emit light you have to somehow exceed it's ionization energy   

       let's say you know the ionization energy needed for "exciting" atoms in that gas (because that's what you want to do basicaly)   

       Now you have to know if the light you have has enough energy to ionize that gas ... that's actualy easy to find out because the energy you need there can be calculated using this formula E=hv where E is the energy h is plank's constant and v the frequency of the light ... taking this into the account makes it dificult for you to get the red from the gas ... why ? becouse red light doesn't have enough energy to ionize the gas ... why ? because it has a low frequency   

       Ok ... but now people are going to throw eggs at me and say "Hey dumb dude we are talking LASERS here ... powerfull light !" ... well ... you maybe are BUT let's not confuse energy with intensity ... they are two different things ...   

       Theoreticaly you could have any laser in the world and still not be able to ionize a specific gas because you don't have the necesary energy ... although you do have intensity   

       Example ? just easy ... take a powerfull laser and shine it on a green fluorescent marker (you know ... those fancy marker pens that "shine" in sun light) surprise ... no fluorescence ... than take a little blue led and shine it on the marker ... result ? the marker exhibits a shiny beautyfull green light ... because of the excitation of the atoms inside the dye from the marker pen ... why that ? blue light has higher energy then red one ... much higher   

       Well ... back to your display ... i could have an ideea to overcome the energy deficit ... say you don't have enough energy from the laser ... what do you do ? compensate :-) something just like in geiger muler counters (you know ... the ones used to measure radiation levels) let me give you an example (the values are not relevant ! just examples !) say your gas needs 10J to ionize and emit light ... you could give it like 9J from an electric source (say a high voltage power source) ... at this stage the gas does not glow ... because it still needs 1J ... witch you maybe guess ... you have from your laser so ... 9J(electric)+1J(optic)=10J voila ! ionization energy of the specific gas (geiger muller way :-))   

       Ok ... i've seen that you said something about using more lasers for a single collor ... if you meant that like to get it brighter or so ... just leave it go :-) you can't use more than one laser for the same hologram (for the same image) why ? because the two beams forming the hologram (object beam and reference beam) must be in phase with each other and have the exact same wave length and there is no possible way you can achieve the same phase from two lasers   

       well ... for more info ... i'll stick arround :-)   

       sorry for my bad english :-)
Alex`, Apr 26 2007


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