Three-dimensional photopolymerization additive manufacturing technology based on two-photon polymerization

In this paper, we examine the trends, technologies, and future development directions of three-dimensional photopolymerization additive manufacturing process technology based on two-photon polymerization reaction. Three-dimensional photopolymerization additive manufacturing, primarily utilizing two-photon polymerization (TPP), is increasingly adopted for the fabrication of micro- and nanoscale structures due to its high resolution and shape control flexibility. TPP enables the precise creation of three-dimensional features at the scale of tens to hundreds of nanometers through a two-photon absorption mechanism, which confines the photopolymerization reaction to a focused area. Despite its strengths, TPP-based techniques face challenges such as limited printing speeds due to narrow fields of view in high-resolution systems and a restricted variety of usable materials. Recent advances in scanning systems, parallelization techniques, photoreactive materials, and faster photopolymerization processes are actively addressing these limitations. As a result, TPP technology is poised for broader industrial applications, especially with the integration of direct laser writing (DLW) and spatial light modulator (SLM) or digital micromirror device (DMD) systems, which enhance efficiency and scalability.