When is the last time you were wowed by a hologram? Let’s be honest, the shiny stickers just aren’t doing it for us anymore. The next step in holography needs to actually be a step up. Plasma-based, 3D displays that you can touch (and can react to your touch) should do the trick.
Researchers from the Digital Nature Group (DNG) at Japan’s University of Tsukuba, the same group that created incredible three-dimensional acoustic levitation, is now reporting that it has come up with a way to render touchable, aerial images in real-time using lasers, mirrors, lenses, and clever programming.
These tiny displays work because lasers can impart enough energy to air that the air’s electrons fly off. This process of ionization causes the excited air to emit light at is becomes a plasma. The DNG team uses unimaginably fast femtosecond laser pulses — a femtosecond is to a second as one calorie of energy is to a megaton of exploding TNT — controlled by a computer to excite as many as 200,000 places per second in mid-air, and in three dimensions. These "voxels,” like pixels but in 3D, make up the "fairy lights” and are safe to the touch.
But safe-to-touch plasma, a consequence of the laser’s speed, is not the only innovation here. Because the DNG’s laser can fire so fast, a camera placed below the display allows the computer-controlled apparatus to react to interaction in real-time. For example, you can try to break a plasma heart and it will respond.
The next step for the DNG is to make the holograms larger, and to make use of more materials than just air. The same set-up could be used to make displays in everything from florescent plates to water. One day this kind of light show might even form the basis of a Minority Report-style haptic display that you can actually feel respond to your touch.