Hybrid two-photon polymerization and single-photon tomographic volumetric additive manufacturing

We introduce a dual-mode excitation strategy that integrates two-photon polymerization (2PP) for high-resolution, localized spatial control with single-photon Tomographic Volumetric Additive Manufacturing (TVAM) for rapid, high-throughput 3D fabrication. Experimentally, a glass vial containing a photocurable resin is illuminated with tomographic light patterns from multiple angular directions, while a glass rod serves as the build platform and is synchronized with the rotation of the vial. When the accumulated light dose from the projected patterns exceeds the polymerization threshold of the resin, localized polymerization is initiated on top of the glass rod. Overprinting enables flexible access to the target surface for subsequent 2PP. Without removing the sample or performing post-processing, we demonstrate finely printed structures using 2PA with a tightly focused femtosecond laser beam at 780 nm, fabricated both inside (embedded) and on the surface of millimeter-scale TVAM-printed objects. This scalable approach holds strong potential for biomedical and micro-optical applications.