Researchers create the world's first 'true' 3D color hologram

Shawn Knight

TechSpot Staff
Staff member

Researchers from the Electronics and Telecommunications Research Institute (ETRI) have developed what they’re calling the world’s first true 3D colored hologram.

ETRI, a 16-company consortium led by LG Display, successfully created a floating Rubik’s cube atop a tabletop-style digital display system. As Engadget points out, the team employed powerful, rapid lasers to create the 3D object using diffraction. Color, meanwhile, is a result of interference between multi-hued lasers.

Implementations already on the market are simply pseudo holograms that achieve a 3D effect through the use of 2D imagery whereas ETRI’s solution can be viewed in 360 degrees.

ET News notes that the research is part of the Giga Korea Project’s Digital Holographic Tabletop Terminal Technology Development that began in 2013.

As you can see, the hologram is pretty small, measuring just three inches in size. Over the next five years, however, researchers said they plan to develop system minimization technology, improve the overall quality of the hologram image and increase its size.

Upon completion in 2021, they hope to create a 10-inch Holo TV. Perhaps even more interesting is the fact that they want to develop a method to send and receive actual holograms over 5G networks.

ETRI Broadcast Communication Media Laboratory manager Kim Jin Woong said the work is a new attempt to overcome technical limitations that current methods have. The progress made thus far has been meaningful, Woong added, as it increases the possibility of implementing virtual reality or holographic broadcasting in the future.

Images courtesy ET News

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'true' hologram - that's a laugh. Color 3D holograms have been around for a while, some are really astounding, like this one:



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I'll speculate that the holograms in the video are holograms that are not produced in the same way as the ones in this announcement. In fact, I would be surprised if the holograms in the video are true holograms produced by illuminating the objects in the scenes, e.g., the rhino, tiger, etc, with a laser - as I understand the subject, illumination with a laser is absolutely necessary to produce a true hologram. Certainly, the tiger over the heads of people looks to me like it is simply projected on a screen that is over their heads.

I'll keep the technical details to a minimum, but making a true hologram of a person with a laser is not an easy task as even blood flow in a person's body can "spoil" the hologram unless the "flash" of light from the laser is significantly shorter than the duration of a flash from a typical flash on any digital camera these days. It has to do with the fact that even the blood flow will produce a movement in the skin of a person that is significantly larger than a wavelength of light, 400 - 700 nanometers for visible light, and if that happens the interference pattern will not be accurately recorded and that spoils the hologram. In fact, if there is any movement, it must be less than the wavelength of light, otherwise, the interference pattern will be destoryed. A hologram comes from recording the interference pattern that is made between a reference laser beam and the laser light that is reflected of the object being recorded. In some ways, it is quite different from a typical photograph.

As to why the hologram in this announcement is so small - it has to do with a property of lasers called "the coherence length of the laser" as I understand it. I'll speculate that the coherence length of the lasers used to record the image from this announcement is approximately 6-inches. IIRC, the laser's coherence length must be approximately twice the depth of the of the object.
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