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Strong collective currents of gold nanoparticles in an optical vortex lattice
preprintposted on 2023-11-30, 17:22 authored by R. Delgado-Buscalioni, M. Meléndez, J. Luis-Hita, M. I. Marqués, J. J. Sáenz
Self-organized collective behaviour of active units is inspiring new designs of artificial swarms of micron-sized objects. However, active control at the nanoscale remains elusive. We have accurately solved the collective optofluidic dynamics of gold plasmonic 50 nm-radius nanoparticles moving in aqueous solution under a nonconservative optical vortex lattice. Above a critical field intensity and concentration, the interplay between optical forces, thermal fluctuations and hydrodynamic pairing leads to a spontaneous transition towards synchronised motion exhibiting a rich assortment of collective dynamics. The critical phenomenon creates strong unidirectional currents of nanoparticles, reaching speeds of centimeters per second along the diagonals of the lattice.