The Influence of Photoinitiator Concentration on the Two-Photon Polymerization Threshold of Pentaerythritol Triacrylate (PETIA) Monomer

As an important three-dimensional (3D) microfabrication technique, two-photon polymerization has attracted much interest in scientific sectors due to its ability to fabricate sophisticated 3D structures with dimensions beyond the diffraction limit using diverse materials. In this work, the interaction between 80 femtosecond laser pulses generated with an Ytterbium-doped Potassium Gadolinium Tungstate (Yb:KGW) laser source and a transparent negative photoresist is comprehensively investigated. The results confirm that the photoinitiator concentration directly affects the range of acceptable average laser power, from the polymerization threshold up to the damage threshold, and subsequently the integrity of manufactured structures.