Robust vortex beam trapping for deterministic nanoscale positioning of metallic nanoparticles on solid surfaces

Deterministic nanoscale positioning of metallic nanoparticles is critical for constructing functional nanophotonic and plasmonic devices. Here, we demonstrate robust on-surface trapping and manipulation of individual gold nanoparticles using tightly focused optical vortex beams. This approach offers three key advantages: (i) nanometer-level positioning accuracy on solid substrates, (ii) broad compatibility with particle sizes spanning micrometers to the submicrometer regime, and (iii) high reproducibility with negligible photothermal damage. Leveraging these capabilities, we achieve reliable assembly of plasmonic nanoplates into user-defined geometries and construct plasmonic dimer nanocavities. These results establish a simple, non-destructive, far-field strategy for deterministic assembling functional plasmonic nanostructures with precise spatial control. The method provides a cost-effective platform for designing quantum photonic devices, enhancing light–matter interactions, and enabling next-generation integrated nanophotonic systems.