• Abstract 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.
Article Summaries:
- Researchers have experimentally realized a three‑dimensional, all‑dielectric photonic topological insulator that exhibits a complete photonic bandgap and robust, spin‑momentum‑locked surface states. The study shows that open boundaries of the structure support gapless topological surface modes that couple to the radiative continuum, effectively functioning as metasurfaces. The helical nature of these surface states allows control of far‑field emission through a pseudo‑spin degree of freedom. By further structuring the interfaces, the team demonstrates enhanced manipulation of emission directionality and radiation patterns, highlighting a new route for designing spin‑dependent photonic devices.
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