3D printers are useful devices for all kinds of reasons, but most have a critical weakness: they simply take a long time to actually make anything. That’s because additive manufacturing generally works by putting down an object one microscopic layer at a time. But a new holographic printing technique makes it possible to create the entire thing at once — in as little as a second or two.
Light-based 3D printing techniques generally use lasers to cause a layer of resin to harden in a pattern, but like extrusion printers, they have to do it layer by layer. If the laser shined all the way through the liquid resin, it would cause a big line of it to cure.
But what if you shined multiple weaker lasers through the resin, none of which was powerful enough to cure it except when they all intersected? That’s the …