Yoichi Ochiai and colleagues presented an interesting volumetric display at SIGGRAPH in June. Their technology projects 3D holographic images in open air—which looks really, really cool!
The basic principle is to use very short laser pulses to ionize air (or water or other) molecules, creating a tiny flash. The optical system guides the laser to paint these miniscule voxels to create 3D images floating in the air. Coupled with camera tracking to detect motion, the system is responsive to touch and interactive. Cool!
Their longer paper gives more background, indicating that using really short pulses (femtoseconds) is important, as this reduces the danger from these tiny lightning bolts.
One of the intriguing possibilities is that the little explosions are potentially detectable by human touch. This means that the voxels can potentially “push back”, and provide haptic feedback, at least in a limited form. That would be interesting!
Of course, there are limitations. Aside from power considerations, the display in air is monochrome. (They say they can do color in water or other materials.) It isn;t clear to me what geometric constraints may be. Obviously, there has to be a path for the laser to reach the area to be illuminated. And the person has to be near enough to touch. But how the optics and the person constrain each other, I can’t tell.
The haptic feedback sounds cool–I mean, the same physical effect giving light and touch (and, by the way, sound). But it is a pretty feeble effect. That’s good for safety, but limits the applications.
(Caveat: I am far from expert in this area, so you would be wise to check out the paper and other information yourself.)
- Ochiai, Yoichi, Kota Kumagai, Takayuki Hoshi, Jun Rekimoto, Satoshi Hasegawa, and Yoshio Hayasaki, Fairy Lights in Femtoseconds: Aerial and Volumetric Graphics Rendered by Focused Femtosecond Laser Combined with Computational Holographic. 2015. http://arxiv.org/abs/1506.06668
- Ochiai, Yoichi, Kota Kumagai, Takayuki Hoshi, Jun Rekimoto, Satoshi Hasegawa, and Yoshio Hayasaki, Fairy lights in femtoseconds: aerial and volumetric graphics rendered by focused femtosecond laser combined with computational holographic fields, in ACM SIGGRAPH 2015 Emerging Technologies. 2015, ACM: Los Angeles, California. p. 1-1.