Krishnamoorthy H N S, Adamo G, Yin J, Savinov V, Zheludev N I, Soci C
Centre for Disruptive Photonic Technologies, TPI, SPMS, Nanyang Technological University, Singapore, 637371, Singapore.
Optoelectronics Research Centre & Centre for Photonic Metamaterials, University of Southampton, London, SO17 1BJ, UK.
Nat Commun. 2020 Apr 3;11(1):1692. doi: 10.1038/s41467-020-15444-0.
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 BiTe 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，高折射率介电材料在纳米光子器件及应用中有着巨大需求。在此，我们通过报道硫族化物晶体中的超材料共振在中红外波段内良好维持，并选择BiTe作为该材料家族中的案例研究，表明硫族化物拓扑绝缘体是红外光谱范围内介电纳米光子学架构的特别合适的候选材料。由于在整个2 - 10μm区域内折射率异常高，介于7到8之间，实现了对入射电磁场的强共振调制。对超材料中复模式结构的分析暗示了圆形表面电流的激发，这可能通过与自旋极化拓扑表面载流子耦合，为增强光与物质相互作用和低损耗等离子体配置开辟途径，从而为在单一平台上结合介电、等离子体和磁性超材料提供新机会。
