Plasmon-induced Lorentz forces of nanowire chiral hybrid modes

Matthew Moocarme,Benjamin Kusin,Luat T Vuong

doi:10.1364/ome.4.002355

Abstract

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.

Highlights

We examine the behavior with numerical simulations of a gold nanowire illuminated with linearly-polarized light at different orientations of a 1025nm-long, 75nm diameter gold nanowire in water
Where E is the electric field, and B is the magnetic, ρ is the charge density, v is the velocity of the electron gas, ε0 is the permittivity of free space, J is the current density
They exhibit complex and rich dynamics associated with chiral hybrid modes excited on metallic nanowires; orientations show stable, unstable, saddle points and even stable limit cycles that lead to and explain the complicated motion observed experimentally

Summary

Introduction

We examine the behavior with numerical simulations of a gold nanowire illuminated with linearly-polarized light at different orientations of a 1025nm-long, 75nm diameter gold nanowire in water. The time-averaged Lorentz force per volume is attributed to electric and magnetic fields:

Results

Conclusion