FIG. 18.
The laser direct writing for fabricating 3D microfluidic devices begins with a stack of paper. The paper is impregnated with a photopolymer and then exposed to a UV laser beam with Gaussian intensity to irradiate the material. The desired pattern is then traced onto the material with the high-intensity laser. The multilayer stacks are placed in a solvent for the development of the final 3D structure.145 Reproduced with permission from He et al., Lab Chip 16, 3296–3303 (2016). Copyright 2016 Royal Society of Chemistry.