A one-dimensional plasmon-polariton which is characterized by non-linear dispersion is supported by electromagnetic field interacting with topologically protected helical state. The electronic helical state arises at the surface of topological insulator in the close proximity of the ferromagnet. In a two-dimensional Dirac magnet these electro-optical excitations are limited by domain walls. Topological electronic imagining of domain walls can provide generally a novel tool to couple magnetic

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... amics with both transport and optical properties of helical electronic states An exact dispersion relation for the topological plasmonpolariton were obtained.