Material Photophysics for Two-Photon Polymerisation: Nonlinear Absorption, Threshold Chemistry and Voxel Growth
Segurola, Juan
2026-08-21 · Report · Version 1.1
Two-photon polymerisation (2PP) localises photochemistry within the focal volume of an ultrafast laser, but the eventual polymer voxel is not determined by optics alone. Molecular absorption cross section, excited-state pathways, initiator solubility and efficiency, sensitisation, radical diffusion, oxygen inhibition, resin reactivity and network formation all influence the exposure threshold and the growth of the polymerised region. Primary studies show that molecular design of two-photon initiators can change fabrication thresholds and usable process windows, that unusually sensitive hybrid photoresists can raise writing speed while preserving nanoscale features, and that single-photon pre-sensitisation can lower the required femtosecond-laser threshold and alter voxel-growth dynamics. This Engineering Review develops a material-centred qualification framework separating nonlinear excitation, initiation, polymerisation threshold, voxel growth and final network response. Generic numerical power/scan-speed calibration, which is system-specific, is intentionally outside scope. 3Dresyns 2PP products are included only as commercial implementation examples and are not assigned threshold or voxel metrics without independent measurement.