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Robust topologically protected transport in photonic crystals at telecommunication wavelengths

An Author Correction to this article was published on 17 December 2018

This article has been updated


Photonic topological insulators offer the possibility to eliminate backscattering losses and improve the efficiency of optical communication systems. Despite considerable efforts, a direct experimental demonstration of theoretically predicted robust, lossless energy transport in topological insulators operating at near-infrared frequencies is still missing. Here, we combine the properties of a planar silicon photonic crystal and the concept of topological protection to design, fabricate and characterize an optical topological insulator that exhibits the valley Hall effect. We show that the transmittances are the same for light propagation along a straight topological interface and one with four sharp turns. This result quantitatively demonstrates the suppression of backscattering due to the non-trivial topology of the structure. The photonic-crystal-based approach offers significant advantages compared with other realizations of photonic topological insulators, such as lower propagation losses, the presence of a band gap for light propagating in the crystal-slab plane, a larger operating bandwidth, a much smaller footprint, compatibility with complementary metal–oxide–semiconductor fabrication technology, and the fact that it allows for operation at telecommunications wavelengths.

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Fig. 1: Schematic and operation principles of the photonic-crystal-based topological insulator.
Fig. 2: Scattering-free edge state in the photonic-crystal-based topological insulator.
Fig. 3: Observation of topologically protected propagation in a photonic-crystal-based topological insulator.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

Change history

  • 17 December 2018

    In the version of this Letter originally published, Fig. 5g in the Supplementary Information was missing the scale bar. This has now been corrected.


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This work was supported by Army Research Office grants W911NF-15-1-0152 and W911NF-11-1-0297. The authors acknowledge discussions with A. Khanikaev.

Author information




M.I.S. and N.M.L. proposed the initial idea. M.I.S. and W.W. designed and performed the analytical and numerical analysis of the structure. M.I.S. fabricated the sample, performed the experimental measurements and analysed the results. A.T. and Y.X. assisted with the fabrication and measurement process of the sample. W.W., M.I.S. and N.M.L. co-wrote the manuscript. N.M.L. supervised the work.

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Correspondence to Natalia M. Litchinitser.

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The authors declare no competing interests.

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Supplementary information

Supplementary Sections A–D

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Shalaev, M.I., Walasik, W., Tsukernik, A. et al. Robust topologically protected transport in photonic crystals at telecommunication wavelengths. Nature Nanotech 14, 31–34 (2019).

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