Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Plasmonic nanostructures provide strong optical near-fields for trapping and manipulating nanosized particles, but converting these interactions into robust directional transport has remained challenging. Here we demonstrate a plasmonic Brownian ratchet that rectifies colloidal diffusion using an asymmetric gold nanoarray under continuous-wave illumination. Finite-element simulations reveal anisotropic near-field distributions that bias optical forces, and experiments confirm directed motion for 40–200 nm nanoparticles of various compositions (dielectric, semiconducting and metallic). We show that, under periodic light modulation, nanoparticles undergo unidirectional lateral transport with velocities up to 2.4 μm/s at incident intensities below 1 kW/cm 2 . These results establish plasmonic ratcheting as an efficient route to bias transport of nanosized analytes, achieving markedly higher speeds and lower operating powers than previous optical ratchets, and opening opportunities for integration into nanophotonic and lab-on-chip systems.
Source: Nano Letters
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4416718780