In 2006, AIST (Japan’s National Institute of Advanced Industrial Science and Technology) developed the first 3D image projector. “How does it work?” you say? From Pink Tentacle:
The newly developed device … creates “real” 3D images by using laser light, which is focused through a lens at points in space above the device, to create plasma emissions from the nitrogen and oxygen in the air at the point of focus. Because plasma emissions continue for a short time, the device is able to create 3D images by moving the point of focus.
Essentially, the laser IGNITES AIR to create a pixel. So, I wouldn’t suggest touching it. lawlz.
Here‘s one more article about the update of the projector.