Spatiotemporal Reaction Dynamics Control in Two-Photon Polymerization for Enhancing Writing Characteristics

Since 2001, 3D microfabrication based on two-photon polymerization (TPP) has drawn extensive attention and interest in biology, optics, photonics, material science, and high-energy physics. The in-volume fabrication capability due to the threshold behavior of two-photon absorption enables TPP higher flexibility compared with other nanofabrication techniques. However, as determined by the in-volume fabrication feature as well as various reaction dynamics, the writing characteristics of TPP, such as throughput, accuracy, surface quality, and fabrication capability, are still limited. Herein, a comprehensive study is performed on the spatiotemporal behavior of reaction dynamics during TPP fabrication, mainly focusing on spatiotemporal characteristics of radical diffusion, photothermal effect, microscale mechanics, and voxel stacking process. Based on the study, a nonsequential fabrication method is established to simultaneously improve key writing characteristics of TPP and realize sharp features, high speeds, large overhang structure, and smooth surfaces. The method established in this work can be applied to improve the performance of functional devices for various fields. In this study, radical diffusion, structural mechanics, thermal accumulation, and the formation of surface morphology during the two-photon polymerization (TPP) process are investigated. A nonsequential scanting strategy is established to enhance the writing resolution, structural limit, surface smoothness, and throughput of the TPP process. Scale bar:3 mu m. image