Helical metasurfaces based on topological surface states in three-dimensional photonic topological insulators

Nature Materials (2026)Cite this article Topological photonics expands the landscape of artificial electromagnetic materials and provides a variety of responses via robust boundary modes. Three-dimensional photonic topological insulators are predicted to host robust spin–momentum-locked surface states. However, their all-dielectric experimental realization has remained a fundamental challenge. Here we demonstrate a practical realization of a three-dimensional all-dielectric photonic topological insulator. We show a complete photonic topological bandgap as well as gapless topological surface states trapped on open boundaries of topological systems. The coupling of these states to the radiative continuum offers opportunities for controlling the emission of electromagnetic waves. We unveil that open interfaces in three-dimensional photonic topological insulators behave as effective metasurfaces and show that the helical nature of topological surface states supported by the interfaces enables control over far-field emission via the pseudo-spin degree of freedom. Further structuring of the topological interfaces provides further enhancement of such effective metasurfaces by offering control over far-field radiation patterns and directionality of the surface state emission.This is a preview of subscription content, access via your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any timeSubscribe to this journal Receive 12 print issues and online access $259.00 per yearonly $21.58 per issueBuy this articleUSD 39.95Prices may be subject to local taxes which are calculated during checkoutAll relevant data are available within the article and Supplementary Information. 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A.P.S. has not been affiliated with ITMO University since December 2024.Alexey P. SlobozhanyukPresent address: , Dubai, United Arab EmiratesSchool of Physics and Engineering, ITMO University, Saint Petersburg, RussiaDmitry V. Zhirihin, Mikhail S. Sidorenko, Alina D. Rozenblit, Georgiy D. Kurganov, Maxim A. Gorlach, Dmitry S. Filonov & Alexey P. SlobozhanyukNonlinear Physics Centre, Research School of Physics, Australian National University, Canberra, Australian Capital Territory, AustraliaYuri S. KivsharDepartment of Physics, The University of Hong Kong, Pok Fu Lam, Hong KongYuri S. KivsharSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarD.V.Z., A.P.S. and Y.S.K. conceived the research idea. D.V.Z. planned and supervised the project. D.V.Z., M.S.S. and A.P.S. developed the designs for 3D PTIs and performed the initial numerical calculations, optimizations and experimental investigations. D.V.Z., M.S.S., A.D.R., G.D.K. and D.S.F. contributed to the experimental investigation at different stages of the project. D.V.Z. and M.S.S. designed and conducted the initial experiments. A.D.R. extracted dispersion diagrams from the measurements. A.D.R. and G.D.K. demonstrated numerically and experimentally the robustness of the topological states. M.A.G. and A.D.R. performed the theoretical analysis. G.D.K. developed an optical design for a 3D PTI. All authors engaged in thorough discussions and contributed to the paper.Correspondence to Dmitry V. Zhirihin or Alexey P. Slobozhanyuk.The authors declare no competing interests.Nature Materials thanks the anonymous reviewer(s) for their contribution to the peer review of this work.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Supplementary Notes 1–11, Figs. 1–18 and References.Extracted dispersion of topological boundary modes.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.Reprints and permissionsZhirihin, D.V., Sidorenko, M.S., Rozenblit, A.D. et al. Helical metasurfaces based on topological surface states in three-dimensional photonic topological insulators. Nat. Mater. (2026). https://doi.org/10.1038/s41563-026-02488-8Download citationReceived: 22 September 2023Accepted: 07 January 2026Published: 12 February 2026Version of record: 12 February 2026DOI: https://doi.org/10.1038/s41563-026-02488-8Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative