Optimizing dimensional accuracy in two-photon polymerization: Influence of energy dose and proximity effects on sub-micrometric fiber structures

Two-photon polymerization (2PP) is a powerful technology for achieving sub-micrometric precision in additive manufacturing, enabling the fabrication of 3D fibrillar structures with sub-micrometric fibers. This study provides an extensive study of the parameters that influence the dimensional accuracy of suspended beams, such as energy dose and proximity effects between the surrounding supportive structures and the fibers. Through systematic characterization of these parameters, we analyze the impact of spatial confinement on fiber width, height, and structural stability. Our results reveal that beyond conventional parameters like energy dose, long-range proximity effects induced by oxygen depletion and diffusion significantly influence final feature dimensions. These findings provide insights into optimizing 2PP for high-resolution, reproducible structures, advancing its application in fields where nanoscale precision is essential, such as tissue engineering and photonics.