Fabrication of true 3D polymer nanostructures with sub-100 nm feature sizes via femtosecond direct laser writing based on two-photon polymerization

Abstract : In this work, we demonstrate the capability to fabricate three-dimensional (3D) structures with 75 nm resolution using direct laser writing (DLW) based on two-photon polymerization. The composition of the photopolymerizable solution was tuned in order to show a strong chemical non-linearity effect by adding free radical inhibitors. The influence of the inhibitor concentration, laser power and scan speed on the resolution of as-prepared structures is also investigated. It is observed that, with the optimized inhibitor-containing formulation, the resolution is significantly improved as the scan speed increased (400 µm/s).