According to this 3D Printing Video, we can use laser-generated, hologram-like 3D images flashed into photosensitive resin. This is what the researchers at Lawrence Livermore National Lab, along with collaborators at UC Berkeley, the University of Rochester, and the Massachusetts Institute of Technology (MIT), have discovered. The researchers learned that they can build complex 3D parts in a fraction of the time of traditional layer-by-layer printing.
The “volumetric” 3D printing process creates parts by overlapping three laser beams that define an object’s geometry from three different directions, creating a 3D image suspended in the vat of resin. The laser light, which is at a higher intensity where the beams intersect, is kept on for about 10 seconds, enough time to cure the object.