Plasmon-induced Lorentz forces of nanowire chiral hybrid modes

The mechanical forces associated with surface currents are widely overlooked and point to a new family of plasmonically-driven processes. Here, we investigate the Lorentz forces acting on a free electron gas that is bound to the surface of a nanowire. We demonstrate that appreciable mechanical forces are produced by longer illumination wavelengths between longitudinal and transverse absorption resonances via the excitation of chiral hybrid plasmon modes. We are the first to associate plasmonic activity as the underlying mechanism for nanowire rotation, which explains prior experimental results. The presence of chiral hybrid plasmon modes yields the greatest net translation and torque forces. The asymmetric plasmon behavior subsequently affects the complex nonlinear dynamics of plasmonic nonspherical nanoparticles in fluids. (C) 2014 Optical Society of America