PsiQuantum has a plan to make a massive quantum computer out of light

MIT Technology Review 

The company has drawn governments, a major chipmaker, and the Pentagon into an effort to control fragile photons and build a useful quantum machine. It aims to be the first. PsiQuantum aims to build a quantum computer that can solve some of science's hardest problems. Its chips, cut from wafers like the one shown here, will perform computations using photons, the particles of light. The machine that could change the world will be housed in a room that looks like a data center crossed with an ice cream factory. Inside will be some 100 stainless-steel cabinets, each about six feet tall and connected to a supply of liquid helium that keeps them only a few degrees above absolute zero. Inside those cabinets will be hundreds of chips, and on those, thousands of particles of light flying through a maze of optical switches and beam splitters.