Formation of Non-reciprocal Bands in Magnetized Diatomic Plasmonic Chains

TL;DR

This paper demonstrates the formation of non-reciprocal plasmonic bands in a magnetized diatomic chain, revealing how broken symmetries lead to directional energy guiding useful for one-way waveguides.

Contribution

It provides a theoretical analysis linking symmetry breaking to non-reciprocal spectral features in magnetized plasmonic chains, guiding design of unidirectional waveguides.

Findings

Non-reciprocal bands are formed in magnetized diatomic chains.

Spectral non-reciprocity is linked to broken spatial-temporal symmetries.

Strong directional energy guiding occurs near the lightline.

Abstract

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