Touchable Holograms Coming to A Reality Near You

by Monica Joshi

Holograms seem to just be things of science fiction. Her, The Giver, Total Recall and Star Wars have all enticed our imaginations to ponder on their possible reality. Moreover, we were always a bit curious to see if we could just walk through them, like in Jurassic World, or if we'd be able to touch them. At Digital Nature Group, Yoichi Ochiai and his fellow researchers were able to touch a small, holographic image of a fairy – almost as though it were real.

The image feels rough, almost like sandpaper, appearing only when the scientist flicks on a switch. The team has been using a host of lasers, lenses and mirrors to create holograms suspended in the air that humans can touch. Holograms have now moved away from two-dimensional surfaces and have now entered the limitless three-dimensional world. Since these holograms are touchable, they could become interactive, so that when you touch a check box, floating in air, a tick could appear on it.

These holograms are created by the team using a laser that fires ultra-short bursts of light. The light is the length of femtoseconds (a quadrillionth of a second). That's really really (add in some more "really"s) short. The laser is concentrated on a region of air molecules and gives them enough energy for them to ionize, release an electron, and emit light. The resulting concentrated mix is called a plasma.

What makes it possible to interact with the holograms is precisely this plasma. When human skin comes into contact with it, the skin senses the hologram from the vibrations of the energetic air molecules. While the lead investigator, Ochiai, said that the hologram feels like sandpaper, other participants and researchers in the study likened it more to a sort of static shock.

The hologram, according to Ochiai, can be programmed to change when you touch it. How cool is that? Touches are registered using a camera positioned under the hologram, which are then used to relay the "touch" information back to a computer. The computer then changes the holographic image.

The short pulses of light were specifically used to save human skin from burns. Using longer-length pulses, on the scale of nanoseconds, to create holograms has burned human skin in the past. The problem with longer-length pulses is also that the resolution isn't as high.

As the speed of the laser pulses has to be so fast, the images that are created by these ingenious lasers are currently around 1 cm in size. It would be fascinating to see larger-scaled images and different textured holograms in the future. As they are created with the help of reflections, it is perfectly possible that these images can be expanded and altered to fit in different, even more complex textures, sizes and other details.

PHOTO CREDIT: GGutulof/Shutterstock