The fundamental principle behind DLW is based on two-photon polymerization (2PP). In this process, a femtosecond laser emits pulses of light that are focused through a microscope objective into a photosensitive resin. The energy from the laser causes the resin to undergo a photopolymerization reaction, solidifying only in the focal volume of the laser. By moving the laser focus in three dimensions, complex 3D structures can be created layer by layer.
