The Birth of Stereolithography (Laser)
3D Printing Materials

It was 1984… Alain Le Méhauté approached the CNRS and the author to discuss Battelle’s patents, as he wanted to put into practice what he had read: using lasers to create three-dimensional objects. The goal was to create 3D parts using photophysical methods and lasers through light excitation (two-photon excitation from two light sources), exploiting a process of nonlinear light absorption. Upon decomposition, electronically excited molecules (photochemical initiators) were expected to trigger polymerization reactions and, as a result, transform a fluid (the monomer/resin) into a solid (the polymer). As in a construction using building blocks (such as bricks called voxels), light beams were moved (at least on paper) to gradually build the desired object....