Coupled Topological Surface Modes in Gyrotropic Structures: Green's Function Analysis

Abstract

At a transition in a wave-guiding structure, part of the incident energy is transmitted and part of the energy is reflected. When the waveguide has non-trivial topological properties, however, the transition may occur with no backscattering, and with unusual modal coupling/transformations. Within this context, we discuss the response of a nonreciprocal topological structure composed of two nearby interfaces between oppositely-biased gyrotropic media and an isotropic medium, which support unidirectional surface modes (topological modes). We provide an exact Green's function analysis of this structure, and we discuss how the topological surface modes are modified when the two interfaces are brought closer and eventually merged. We show that the resulting mode conversion is independent of the transition geometry.

References in corpus (7)

• Topological Photonics
• Reflection-Free One-Way Edge Modes in a Gyromagnetic Photonic Crystal
• Floquet Topological Insulators for Sound
• Experimental Observation of Large Chern numbers in Photonic Crystals
• Topological Photonic Phase in Chiral Hyperbolic Metamaterials
• Topological creation and destruction of edge states in photonic graphene
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Cited by in corpus (5)

• Physical Violations of the Bulk-Edge Correspondence in Topological Electromagnetics
• Unidirectional and diffractionless surface plasmon-polaritons on three-dimensional nonreciprocal plasmonic platforms
• Topological origin of electromagnetic energy sinks
• Realization of broadband index-near-zero modes in nonreciprocal magneto-optical heterostructures
• Topological edge states of continuous Hamiltonians