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arXiv · 1706.00059

Observation of Photonic Topological Valley-Hall Edge States

Jiho Noh·Sheng Huang·Kevin Chen·Mikael C. Rechtsman
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Abstract

We experimentally demonstrate topological edge states arising from the valley-Hall effect in twodimensional honeycomb photonic lattices with broken inversion symmetry. We break inversion symmetry by detuning the refractive indices of the two honeycomb sublattices, giving rise to a boron nitride-like band structure. The edge states therefore exist along the domain walls between regions of opposite valley Chern numbers. We probe both the armchair and zig-zag domain walls and show that the former become gapped for any detuning, whereas the latter remain ungapped until a cutoff is reached. The valley-Hall effect provides a new mechanism for the realization of time-reversal invariant photonic topological insulators.

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physics.opticscond-mat.mes-hallcond-mat.quant-gas

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Jiho Noh, Sheng Huang, Kevin Chen, Mikael C. Rechtsman. 2017-05-31. Observation of Photonic Topological Valley-Hall Edge States. https://doi.org/10.1103/physrevlett.120.063902

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