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arXiv · 1804.08707

Pseudospin-valley coupled edge states in a photonic topological insulator

Yuhao Kang·Xiaojun Cheng·Xiang Ni·Alexander B. Khanikaev·Azriel Z. Genack
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Abstract

Pseudo-spin and valley degrees of freedom (DOFs) engineered in photonic analogues of topological insulators (TI) provide potential approaches to optical encoding and robust signal transport. Here we observe a ballistic edge state whose spin-valley indices are locked to the direction of propagation along the interface between a valley photonic crystal and a metacrystal emulating the quantum spin Hall effect. We demonstrate the inhibition of inter-valley scattering at a Y-junction formed at the interfaces between photonic TIs carrying different spin-valley Chern numbers. These results open up the possibility of using the valley DOF to control the flow of optical signals in 2D structures.

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Yuhao Kang, Xiaojun Cheng, Xiang Ni, Alexander B. Khanikaev, Azriel Z. Genack. 2018-04-08. Pseudospin-valley coupled edge states in a photonic topological insulator. https://doi.org/10.1038/s41467-018-05408-w

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