| Abstract Scope |
We present an advanced free-space 3D nanoprinting technique using an optical force brush (OFB) and polymer-free methods, overcoming limitations of traditional 3D nanoprinting. OFB allows precise spatial writing, instantaneous linewidth adjustments, and resolutions beyond optical limits, enabling high-speed (100 to 1000 times faster) printing of 4D nanostructures with tunable mechanical properties and excellent biocompatibility. Additionally, our polymer-free approach employs two-photon decomposition (TPD) and optical force trapping for direct 3D printing of metals, metal oxides, and multimetallic alloys. This method involves TPD of metal atoms, rapid nanocluster assembly via optical forces, and ultrafast laser sintering, producing dense, smooth nanostructures. Enhanced near-field optical forces from laser-induced localized surface plasmon resonance (LSPR) further facilitate nanocluster aggregation. Our technique eliminates the need for organic materials, layer-by-layer printing, and complex post-processing, achieving high-quality metallic nanostructures with superior mechanical properties. This innovation significantly impacts nanoelectronics, nanorobotics, and advanced chip manufacturing. |