Formation of nonreciprocal bands in magnetized diatomic plasmonic chains

Abstract

We show that nonreciprocal bands can be formed in a magnetized periodic chain of spherical plasmonic particles with two particles per unit cell. Simplified forms of symmetry operators in dipole approximations are used to demonstrate explicitly the relation between spectral nonreciprocity and broken spatial-temporal symmetries. Due to hybridization among plasmon modes and free-photon modes, strong spectral nonreciprocity appears in the region slightly below the light line, where highly directed guiding of energy can be supported. The results may provide clear guidance on the design of one-way waveguides.