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arXiv · 2411.13064

Twisted fibre: a photonic topological insulator

Nathan Roberts·Brook Salter·Jack Binysh·Peter J. Mosley·Anton Souslov
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Abstract

The breaking and enforcing of symmetries is a crucial ingredient in designing topologically robust materials. While magnetic fields can break time-reversal symmetry to create Chern insulators in electronic and microwave systems, at optical frequencies natural materials cannot respond to magnetic fields, which presents a challenge for the scalable exploitation of topologically enhanced devices. Here, we leverage the natural geometry of fibre to build a scalable photonic Chern insulator by twisting the fibre during fabrication. The twist inside optical fibre breaks an effective time-reversal symmetry and induces a pseudo-magnetic field, which we observe via photonic Landau levels. Unavoidably, this twist introduces a competing topology-destroying effect through a parabolic profile in the effective refractive index. Using simulations to guide experimental materials design, we discover the Goldilocks regime where the real-space Chern invariant survives, guaranteeing topological protection against fabrication-induced disorder of any symmetry class.

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Nathan Roberts, Brook Salter, Jack Binysh, Peter J. Mosley, Anton Souslov. 2024-11-20. Twisted fibre: a photonic topological insulator. https://arxiv.org/abs/2411.13064

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