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Science Technology

Researchers Create Free-Floating Animated Holograms (gizmodo.com) 44

An anonymous reader quotes a report from Gizmodo: Back in 2018, researchers from Brigham Young University demonstrated a device called an Optical Trap Display that used lasers to create free-floating holographic images that don't need a display. That same team is now demonstrating a new technique that allows those holographic images to be animated: goodbye TVs, hello holodecks. Most 3D holograms require a special screen to be displayed, and even then the 3D effect is limited to a small field of view. Images genuinely look like they exist in 3D space, but step to the side and suddenly you see nothing at all. The approach taken by the researchers at Brigham Young University is radically different. Screens are replaced by lasers: an invisible one that manipulates a tiny opaque particle floating in the air, and a visible one that illuminates the particle with different colors as it travels through a pre-defined path, creating what appears to be a floating image to a human observer. Unlike the restricted viewing angle of traditional holograms, an observer can see these free-floating Optical Trap Display images from any angle and can walk all the way around them without the 3D effect disappearing because the floating images are actually drawn in 3D space.

Three years of improving the technology used in the Optical Trap Displays has now allowed the BYU researchers to take the effect to the next step with animations that play out in front of an observer's eyes in real-time. The team demonstrated the amazing effect with tiny recreations of Star Trek spaceships engaged in a mid-air photon torpedo battle (complete with simulated explosions that look like vector animations straight out of Tron) and even miniature versions of Obi-Wan and Darth Vader dueling with glowing lightsabers made from actual lasers. The researchers have even come up with ways to track the movements of a real-life object and make the free-floating holograms appear to interact with its movements, like an animated stick figure character walking across a human finger. Using optical tricks like playing with perspective and parallax motions, the holograms could even be made to appear much larger than they really are when projected in front of a pair of eyes, so there are some potentially interesting applications when it comes to making viable smart glasses.

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Researchers Create Free-Floating Animated Holograms

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  • The evolution and refinement of these techniques seems only now limited by imagination. I think the real story is how they managed to walk the Star Trek / Star Wars controversy so well.
    • It's a (Fake|Trap)
    • Honestly, I don't think this tech can scale. small air currents would ruin it so it will have to be enclosed. And, how fast can the laser move the particle? I can't imagine this working well at 150 cubic centimeters.
      • Limiting air currents is easy. That's what insulation is.
        The question is how to make it so it's all fully transparent instead of being white to all the non-right angles.

      • Put the thing inside a glass box and you have no air currents except the fairly predictable thermal convection currents.

        > I can't imagine this working well at 150 cubic centimeters.
        I don't know, a 5.3cm cube seems like a fairly workable volume to me. If you assume hundreds or thousands of particles all operating in concert, I could even see an intricately animated 150cm cube being fairly workable.

        But... that would probably get expensive. And it seems likely it will always be far better suited to line-a

        • Put the thing inside a glass box and you have no air currents except the fairly predictable thermal convection currents.

          Now you have a big glass box on your desk. Seems kind of counter to the goal.

          If you assume hundreds or thousands of particles all operating in concert

          As this uses a laser to control the particle, I seems to me one would need hundreds or thousands of lasers to have hundreds or thousands of particles and then one would have to worry about one laser interfering with the particle of another laser. That is why I don't see this method scaling well.

          Could still have all sorts of interesting applications though.

          Tiny simulated space battles FTW!

    • The thing to note here is they still obviously have a fundamental problem with how fast they can move the particle itself. Pay attention and you'll note they've had to alter the video speed to reduce the flickering and make the objects appear solid.
      • Yes, it's a *lot* of volume to scan. You need a *very* fast mirror. Like 2000*2000 vx * 60 fps = 24 *million* 90Â rotations a *second* fast for a single 3D scanning laser!

        All I can think of is using a normal projector and make it do 2000*60 = 120,000 fps(!!!) to get those 2000 layers of 60 fps video.

    • by ceoyoyo ( 59147 )

      No, it's very much limited by how fast you can make a tiny particle move through the air. The display volume is quite small and they can only draw simple stick shapes, and that probably can't be improved much more.

      • by jwhyche ( 6192 )

        What type of particle are you holding? Is it an air particle or what? You hold that with one laser than use another laser to draw on that particle.

        Lets dispense with the laser that does the drawing and only concentrate on the technology that uses a laser to move a particle. Now using several lasers in unison we move parcels in a 2d plane, then employ the lasers to hold said particles in one place. Can such effect be used to create a physical force field?

        • by suutar ( 1860506 )

          Probably, but the power requirements go up very fast as you increase the pressure it's expected to withstand, and in not too long your particles get vaporized. Then what's pressing against them does too. Also your power supply, most likely.

          • by jwhyche ( 6192 )

            Yes, that seems to echo what I'm thinking too. It is theoretically possible, not practical. It's a nice little thought exercise.

        • by ceoyoyo ( 59147 )

          No. Well, not one that would exert a reasonable amount of force without vaporizing you.

  • by Tony Isaac ( 1301187 ) on Thursday May 06, 2021 @09:18AM (#61354416) Homepage

    This reminds me of the old Vectrex video game console, https://en.wikipedia.org/wiki/... [wikipedia.org]. Instead of pixels on a screen, it traced patterns on the screen by moving the single glowing dot like a pen across the screen. Just as displays have gotten vastly better since then, I predict this laser technology will improve dramatically.

    While this is a 3-D display technique, it isn't technically a hologram or holograph, which relies on interference patterns.

    • by arQon ( 447508 )

      Except that vector displays DIDN'T "get vastly better" - they were completely killed off by what actually WAS vastly superior tech for nearly all cases: raster displays.

      While we all share your enthusiasm, it's worth making clear that your optimism is founded entirely on a misunderstanding of history. If this does follow the same path as vector displays, it will (1) never advance any further, and (2) be restricted to a miniscule subset of highly specialised devices / displays.
      IOW, your simile is a dead end,

      • Well, I see you didn't read my post very carefully, but that's OK, who does that!

        The vector part is not the important part. What's important is that display technology got vastly better since Vectrex. The fact that display technology settled on raster technology is immaterial. It still remains that display technology has advanced by orders of magnitude since then.

        Perhaps future mid-air displays will use some kind of raster version of this. Why not? Suspend millions of these glowing particles in midair using

  • by Pinky's Brain ( 1158667 ) on Thursday May 06, 2021 @09:35AM (#61354480)

    This has no more right to be called a hologram than Peppers ghost effects.

  • Very impressive even though the effect is really tiny and they speeded the video up to make it look better. Very early days but I'd highly recommend that you invest in this technology if you get a chance.

    I saw my first practical LCD (on a watch) around 1975 and it wasn't much to look at but look at where LCDs are today, almost 50 years later. Yes, there is going to be a very long payoff period, but if you got in on the ground floor today...

    • by Jamlad ( 3436419 )
      Nah. The fundamental problem is in the name: Optical Trap Display. To create a visible display you have to use a non-visible laser for the trapping and manipulation. That is already a major Hell No from a safety perspective.
      • Seems like a "display" would be encapsulated in say... a hemisphere of glass with a coating that would block that non-visible laser. I mean, given the laser required to move the particle, and the fact that touching the particle would immediately cock things up, I can't imagine this would ever been an "open air" sort of tech.

        • by Jamlad ( 3436419 )
          You could do that, but it would warp the image depending on azimuth angle, but again, it doesn't scale to large proportions. A 6ft hemisphere of glass would be ridiculously expensive, and heavy, you could use plastics but then you increase optical abberations even further. And then how many idiot customers would remove the hemisphere to get a clearer "picture"? At least there was less incenvtive to crack open the back of a CRT beyond technical curiosity. AR would serve much better in nearly all use cases.
  • TFS makes the animation sound better than it is. The ships aren't drawn - only lines for the phaser beams and explosions. It's like computer graphics from the early 1980s.

    Still, it's an interesting idea. The problem will be scaling: to have decent images, you would need a lot of particles, and they will get in each other's way.

    • So you need a lot of particles. That's like complaining that a good OLED monitor requires a lot of LED's. It might be a problem now, but must it continue to be? Why not arrays of these lasers, each controlling one dot?

  • "tiny opaque particle floating in the air"

    • "time lapse"

      seems like it would have nano assembly in about 50 years with this technology but I don't think displays are feasible.

      • "time lapse"

        seems like it would have nano assembly in about 50 years with this technology but I don't think displays are feasible.

        Maybe the issues around the particles could be solved by using two separated glass plates sealed around the perimeter to confine them and stop ambient air currents from disrupting their path.

    • That's not a screen. A screen is a stable surface that light is projected onto. This is actively manipulating the impact location to redirect the light on a point-by-point basis. It is not a plane, it is not fixed, and it is definitely not a screen by any stretch of that term. Under your definition, all objects are just screens.

      • by Tx ( 96709 )

        I take his point though; at the end of the day, the technique is still projecting onto a solid physical object, whether it fits the definition of a "screen" or not. Especially since creating animated holograms you can touch [popsci.com] without projecting onto any solid object, particle or otherwise, has been done, by generating plasma voxels in the air using high-energy lasers. I'm not sure if the latter technique would scale any better than the one in TFA, but interesting comparison anyway.

  • Yoda says, "Luminous beams we are, not this crude matter." :-)

  • This isn't really much of an advancement over the last time they were on Slashdot. The demos they're showing this time around aren't even as impressive as the home-builts.

  • Or are only the surfaces drawn?

  • How fast and how big? Particle gun anyone? Accelerate it to almost light speed and it dont have to be very big particle to do serious damage.
    • by suutar ( 1860506 )

      If you're using a laser to accelerate your particle, then unless you want a "coast" phase (which makes it much more likely your particle will waste itself on something you didn't want hit) you may as well just use it to blast what you want hit.

      • by suutar ( 1860506 )

        Of course immediately after hitting submit I remember that using a laser can add energy to the particle for an arbitrary amount of time, which may work better than trying to get your target to sit still. So the idea may have merit after all.

  • You notice how they all wear goggles? It's because if a strong laser crosses your vision it can cut or cloud your cornea. I have no info on what they are using but that they wear goggles in any of the videos indicates they are not extremely low power. Though it is interesting and the video of a little white stick figure walking across one's leg was intriguing, I have absolutely zero wish to gradually fog my corneas because of being in frequent contact with lasers. It would be far more interesting to me if a

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