Plasmonic analogs of Zitterbewegung in nanoscale metal waveguide arrays

Abstract

We numerically observed plasmonic Zitterbewegung (ZB) in nanoscale binary metal waveguide arrays constructed by alternately filling two different dielectrics into adjacent guides. The positive- and negative-energy states of a relativistic electron, whose interference causes the ZB, are mimicked by surface plasmon polariton modes of the two bands of the guide array, respectively. Different from photonic ZB appearing in dielectric systems, we also found that SPP wave packets satisfy a negative-coupled Dirac equation; hence the beam center of SPP shows a shift direction opposite to photonic ZB.