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> Aside from the fact that it's not in open air I once put a lot of work into researching how to build an "open air" 3d hologram like they have in the movies a

> Aside from the fact that it's not in open air I once put a lot of work into researching how to build an "open air" 3d hologram like they have in the movies and came to the conclusion that it is basically against the laws of physics. This is because its impossible to bend light beams in free space. There are however a lot of cool tricks and hacks, 3d holograms are a really cool subject, this Looking Glass product looks fantastic I want one. One of the biggest problems these kinds of holograms in a box have is, even though horizontal scrolling works fine, being able to look at it from the top and bottom does not. Here [1] is a video of a 3d hologram in a box based on a rotating mirror that has a head tracker for viewing from different vertical angles. It's really cool but the thing rotates so fast it's also extremely dangerous. Another approach for open air 3d holograms is to create a series of small explosions that emit light by shooting dangerous high powered lasers into the air and using plasma emission. See [2] Finally here is a cool video of some fan based holograms [3] [1] https://www.youtube.com/watch?v=8gvPS1m40gw https://www.youtube.com/watch?v=8gvPS1m40gw [2] https://www.youtube.com/watch?v=KfVS-npfVuY https://www.youtube.com/watch?v=KfVS-npfVuY [3] https://www.youtube.com/watch?v=Wjvq0SNczrI https://www.youtube.com/watch?v=Wjvq0SNczrI

colordrops 8y ago
* against the laws of engineering. There's no reason we couldn't come up with something creative once the technology was there. For instance, a magnetic field could keep matrix of tiny particles in the air that could be targeted with lasers that cause the particles to emit light. There's already something along those lines, heating the air enough to form plasma: https://m.youtube.com/watch?v=WkkZcFWgr4Q https://m.youtube.com/watch?v=WkkZcFWgr4Q Very primitive and limited but certainly a proof of concept. Edit: ugh, this is what happens when you don't read a comment fully before replying.
- calhoun137 8y ago
  I thought there might be a way to use constructive and destructive interference of a large number of sources to build an open air 3d hologram out of pure light. If light didn't have to travel in a straight line, and we could control the index of refraction at any point in space, this would probably work.
  - chopin 8y ago
    Standing sound waves could achieve this. Albeit, the change in refractive index is small. Another possibility would be using molecules having a high refractive index when exited. A laser tuned to that would probably work. But that's not exactly in air.
- mlevental 8y ago
  > For instance, a magnetic field could keep matrix of tiny particles in the air that could be targeted with lasers that cause the particles to emit light. irony: this is in fact "against the laws of physics" https://en.wikipedia.org/wiki/Earnshaw%27s_theorem https://en.wikipedia.org/wiki/Earnshaw%27s_theorem
  - akiselev 8y ago
    Yeah, I think what he means to say is ultra minituarized matrix of billions of high powered phased arrays all synchronized to keep billions of charged aerogel-type mm^2 "pixels" with a different angle of refraction as you rotate it and a different excitation at different ... just make it up as you go along, its decades away at best!
    - colordrops 8y ago
      Sounds like you've thought about it though. If we can imagine it, perhaps it's possible. Could anyone have believed that we could control the color of millions of tiny dots on a thin flat surface 100 years ago? My point is that to say that it's against the laws of physics is as ridiculous as my imaginations of what is possible.
ekianjo 8y ago
Look at Voxon for a system that enables you to see things from the top. https://voxon.co/ https://voxon.co/
- artursapek 8y ago
  I saw an early version of this at a meetup they did in a Barcade in Brooklyn... it blew my mind. Back then it was called "Voxie Box"
  - ekianjo 8y ago
    yeah despite the flicker its absolutely impressive to see it before your eyes.
deleted 8y ago
[deleted]
ZenPsycho 8y ago
Maybe it's difficult to get the actual light out into the open air, but there's nothing stopping view dependant parallax from making an image appear "in front" of the display, with the annoying limitation that your object will still be occluded by the bounds of the display. Failing that, you can easily bend lightwaves in open air with a strong enough gravitational field. So there you go, you just need a way to generate enough black holes and position them very precisely. Or... a way to modify the density (and therefore index of refraction) within a volume of air, with perhaps, standing waves.
lvs 8y ago
> This is because its impossible to bend light beams in free space. This isn't strictly true, depending on how you define "free space." In fact, you can bend light at will if you can control gravity. Gravitational lensing is the basis for measuring the mass of distant planets and other such astronomical things. So, all you need to do is curve space-time. Thanks Einstein.

colordrops 8y ago

* against the laws of engineering. There's no reason we couldn't come up with something creative once the technology was there. For instance, a magnetic field could keep matrix of tiny particles in the air that could be targeted with lasers that cause the particles to emit light. There's already something along those lines, heating the air enough to form plasma: https://m.youtube.com/watch?v=WkkZcFWgr4Q https://m.youtube.com/watch?v=WkkZcFWgr4Q Very primitive and limited but certainly a proof of concept. Edit: ugh, this is what happens when you don't read a comment fully before replying.

calhoun137 8y ago
I thought there might be a way to use constructive and destructive interference of a large number of sources to build an open air 3d hologram out of pure light. If light didn't have to travel in a straight line, and we could control the index of refraction at any point in space, this would probably work.
- chopin 8y ago
  Standing sound waves could achieve this. Albeit, the change in refractive index is small. Another possibility would be using molecules having a high refractive index when exited. A laser tuned to that would probably work. But that's not exactly in air.
mlevental 8y ago
> For instance, a magnetic field could keep matrix of tiny particles in the air that could be targeted with lasers that cause the particles to emit light. irony: this is in fact "against the laws of physics" https://en.wikipedia.org/wiki/Earnshaw%27s_theorem https://en.wikipedia.org/wiki/Earnshaw%27s_theorem
- akiselev 8y ago
  Yeah, I think what he means to say is ultra minituarized matrix of billions of high powered phased arrays all synchronized to keep billions of charged aerogel-type mm^2 "pixels" with a different angle of refraction as you rotate it and a different excitation at different ... just make it up as you go along, its decades away at best!
  - colordrops 8y ago
    Sounds like you've thought about it though. If we can imagine it, perhaps it's possible. Could anyone have believed that we could control the color of millions of tiny dots on a thin flat surface 100 years ago? My point is that to say that it's against the laws of physics is as ridiculous as my imaginations of what is possible.

ekianjo 8y ago

Look at Voxon for a system that enables you to see things from the top. https://voxon.co/ https://voxon.co/

artursapek 8y ago
I saw an early version of this at a meetup they did in a Barcade in Brooklyn... it blew my mind. Back then it was called "Voxie Box"
- ekianjo 8y ago
  yeah despite the flicker its absolutely impressive to see it before your eyes.

deleted 8y ago

[deleted]

ZenPsycho 8y ago

Maybe it's difficult to get the actual light out into the open air, but there's nothing stopping view dependant parallax from making an image appear "in front" of the display, with the annoying limitation that your object will still be occluded by the bounds of the display. Failing that, you can easily bend lightwaves in open air with a strong enough gravitational field. So there you go, you just need a way to generate enough black holes and position them very precisely. Or... a way to modify the density (and therefore index of refraction) within a volume of air, with perhaps, standing waves.

lvs 8y ago

> This is because its impossible to bend light beams in free space. This isn't strictly true, depending on how you define "free space." In fact, you can bend light at will if you can control gravity. Gravitational lensing is the basis for measuring the mass of distant planets and other such astronomical things. So, all you need to do is curve space-time. Thanks Einstein.