A lot of work is currently going into creating Star Wars-esque 3D holograms that can be seen by the naked eye without wearing 3D glasses, and now researchers have found a way to make safe, touchable mid-air displays using femtosecond lasers.
It is possible to create holograms in mid-air using a laser-induced plasma display, which works by ionising air molecules so that they release extra energy in the form of bluish-white photons that can be seen easily.
The plasma photons are known as 3D pixels, or rather voxels, and at the moment, the lasers used to make 3D holograms are nanosecond lasers, meaning they fire tens or hundreds of thousands of times per second to heat up specific points of air.
