There are a number of sites around the world that have the technology.
– Scientists are on the brink of turning light into matter—a process first theorized in 1934 but then described by the very men behind the idea as "hopeless to try." The subatomic particles the Imperial College London physicists say they've figured out how to produce will not be visible to the naked eye, but will be "one of the purest demonstrations of E=mc2," Einstein’s famous equation describing the "interchangeable" relationship between mass and energy, the Guardian reports. They think they can attempt the feat in the next 12 months using existing technologies. What'll happen in general: Two particles of light (photons) will be smashed together to create an electron-positron pair, known as a Breit-Wheeler pair in honor of the earlier researchers, Americans Gregory Breit and John Wheeler. The specifics of the process: First a stream of electrons will be fired into a slab of gold, creating a high-energy photon beam; then, a high-energy laser will be fired into a gold can called a hohlraum, creating light akin to what stars emit. The first beam will then be directed into the center of the can, and the two photon sources will collide. What emerges from the can: electrons and positrons. It is "a very clean experiment: pure light goes in, pure matter comes out. This experiment would be the first demonstration of this,” says physicist Oliver Pike. In a letter about their plans published in Nature Photonics, Pike and his colleagues say they are ushering in "the advent of a new type of high-energy physics experiment." (Click to read about another big discovery.)