High-index dielectric materials are in great demand for nanophotonic devices and applications, from ultrathin optical elements to metal-free sub-diffraction light confinement and waveguiding. Here we show that chalcogenide topological insulators are particularly apt candidates for dielectric nanophotonics architectures in the infrared spectral range, by reporting metamaterial resonances in chalcogenide crystals sustained well inside the mid-infrared, choosing Bi₂Te₃ as case study within this family of materials. Strong resonant modulation of the incident electromagnetic field is achieved thanks to the exceptionally high refractive index ranging between 7 and 8 throughout the 2–10 μm region. Analysis of the complex mode structure in the metamaterial allude to the excitation of circular surface currents which could open pathways for enhanced light-matter interaction and low-loss plasmonic configurations by coupling to the spin-polarized topological surface carriers, thereby providing new opportunities to combine dielectric, plasmonic and magnetic metamaterials in a single platform.

从超薄光学元件到无金属亚衍射光限制和波导，纳米光子器件和应用对高折射率介电材料的需求量很大。在这里，我们通过报告在中红外范围内持续良好的硫族化物晶体中的超材料共振，并选择 Bi ₂ Te ₃作为该材料系列中的案例研究，表明硫族化物拓扑绝缘体特别适合用于红外光谱范围内的介电纳米光子结构。由于整个 2-10 μm 区域的折射率在 7 到 8 之间，因此可实现入射电磁场的强谐振调制。对超材料中复杂模式结构的分析暗示了圆形表面电流的激发，这可以通过耦合到自旋极化拓扑表面载流子来打开增强光与物质相互作用和低损耗等离子体配置的途径，从而提供新的结合机会介电、等离子体和磁性超材料在一个平台上。