New Characterization of Plasmons in Nanowire Dimers by Optical Forces and Torques

R. M. Abraham Ekeroth
In a previous work, unexpected optical torques were found on metallic dimers of infinite nanowires. The dimers were illuminated with linearly polarized plane waves. Here, the study is extended to bigger systems: the spin torques are induced independently of scale, shape details, and dielectric corrections. New properties appear in the dynamics as the breaking of the action-reaction law, changes in the radiation pressures, or the detection of forbidden modes—dark plasmons—by optical forces. Furthermore, the spectra of spin torques show more resolved resonances than typical far-field spectra. The numerical study is based on an exact method. New possibilities are suggested for the detection of asymmetries in nanostructures. The results are thought for the design of nanorotators and nanodetectors, or simply approach the movement of coupled particles with more accuracy.

DOI