High precision and continuous optical transport using a standing wave optical line trap.

We introduce the Standing Wave Optical Line Trap (SWOLT) as a novel tool for precise optical manipulation and long-range transport of nano-scale objects at low laser power. We show that positioning and transport along the trap can be achieved by controlling the lateral component of the scattering force while the confinement of the particles by the gradient force remains unaffected. Multiple gold nanoparticles with a diameter of 100 nm were trapped at a power density 3 times smaller than previously reported while their transverse fluctuations remained sufficiently small (±36 nm) to maintain the order of the particles. The SWOLT opens new doors for sorting, mixing, and assembly of synthetic and biological nanoparticles.