One-way helical electromagnetic wave propagation supported by magnetized plasma

TL;DR

This paper demonstrates that magnetized plasma naturally supports one-way helical electromagnetic surface states due to topological effects, offering a simple, experimentally feasible approach to unidirectional photonic waveguiding.

Contribution

It reveals the existence of topologically protected one-way surface states in magnetized plasma without artificial structures, expanding the understanding of topological photonics in natural systems.

Findings

Magnetized plasma supports topologically nontrivial gaps in k space.

Numerical confirmation of one-way, scatter-immune helical surface states.

The scheme is simpler to implement than previous artificial structure-based methods.

Abstract

In this paper we reveal the presence of photonic one-way helical surface states in a simple natural system - magnetized plasma. The application of an external magnetic field to a bulk plasma body not only breaks time-reversal-symmetry but also leads to separation of Equi-Frequency Contour surfaces (EFCs) to form topologically nontrivial gaps in k space. Interestingly, these EFCs support topologically protected surface states. We numerically investigate an interface between magnetized plasma, using a realistic model for parameter dispersion, and vacuum, to confirm the existence of one-way scatter-immune helical surface states. Unlike previous proposals for achieving photonic one-way propagation, our scheme does not require the use of artificial structures and should therefore be simple to implement experimentally.