Longitudinal chirality, particle clusters, and planar nanoscale one-way guiding

When a linear chain of plasmonic nano-particles is exposed to a transverse DC magnetic field, the chain modes are elliptically polarized, in a single plane parallesingle plane parallell to the chain axis. If, in addition, the chain geometry possesses longitudinal rotation, e.g. by using ellipsoidal particles that rotate in the same plane as the plasmon rotation (“longitudinal chirality”), strong non-reciprocity and one-way guiding are created. The geometry is planar and can be fabricated by printing. The bias magnetic field is significantly weaker than that required in previously reported nano-scale one-way waveguides.