Femtosecond lasers are used to create the touchable image.
Holograms have been a staple of science fiction for some years now, in particular in the Star Trek franchise where the holodeck is often portrayed as the ultimate in simulated reality experiences.
While creating entire worlds to walk around in is still quite a few years away yet, researchers in Japan recently demonstrated that creating a physical hologram is something that is genuinely achievable.
The impressive invention uses femtosecond lasers to produce the image of a small fairy in mid air that human observers can actually touch with their finger. It works by agitating particles in the air so that when someone touches it they can feel the image as though it had a solid presence.
The technology could prove particularly useful in the creation of holographic interfaces such as a computer keyboard made of light that can be projected on to a surface.
In the future it may also be possible to use holograms to communicate with another person during a video chat or to provide tactile feedback when playing an online game.