Comment on “Rapid Assembly of Small Materials Building Blocks (Voxels) into Large Functional 3D Metamaterials”

Abstract

In their Progress Report, Hahn et al. assessed the state-of-the-art of 3D printing but excluded temporally focused two-photon polymerization (2PP) from the comparison because they concluded that it does not represent a full 3D printing capability. This comment highlights the flaws in their scientific arguments, clarifies the misinterpretation of private communications, and shows that 3D structures with distinct z-layers can be printed using temporally focused 2PP.