The way this article is being pitched, as scientists having discovered a way of transforming light into matter, is misleading. The method for converting two photons into an electron and a positron was proposed eighty years ago. The problem is and always has been measuring the results.
Strange. I have personally witnessed the creation of electron-positron pairs in a cloud chamber we built at the U of Chicago in 1969. That was some 45 years ago.
It was pretty easy to spot the trail left by the pair, spiraling off as they did in opposite directions from a single point under the force of a powerful magnetic field.
Furthermore, there is no need for two photons, only one, if that collides with a boson or other particle of chargeless mass. In a collision, mass-energy, momentum, charge, spin, strangeness, etc., must be conserved.