Sub-diffractional volume-confined polaritons in the natural hyperbolic material hexagonal boron nitride
Sub-diffractional volume-confined polaritons in the natural hyperbolic material hexagonal boron nitride
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DOI：
10.1038/ncomms6221
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发表时间：
2014-10-01
影响因子：
16.6
通讯作者：
Novoselov, Kostya S.
中科院分区：
文献类型：
--
作者：
Caldwell, Joshua D.;Kretinin, Andrey V.;Novoselov, Kostya S.
强各向异性介质，其中介电张量的主分量具有相反的符号，称为双曲线。这种材料表现出独特的纳米光子特性，这是由于在深度亚衍射长度尺度上局域的慢光模式的高度定向传播而实现的。虽然人工双曲线超材料已被证明，但它们遭受高等离子体损失，需要复杂的纳米加工，这反过来导致光学限制的尺寸依赖的限制。低损耗、中红外、天然双曲线材料六方氮化硼是一种有吸引力的替代材料。在这里，我们报道了三维受限的氮化硼纳米锥中的双曲极化激元，它在两个光谱带中支持四个系列(高达七阶)模式。共振模符合预测的纵横比关系，并在强限制区(最高可达波长/86)表现出高品质因子(Q可达283)。这些观察结果表明，六方氮化硼是研究光-物质相互作用和纳米光子器件工程的一个很有前途的平台。
Strongly anisotropic media, where the principal components of the dielectric tensor have opposite signs, are called hyperbolic. Such materials exhibit unique nanophotonic properties enabled by the highly directional propagation of slow-light modes localized at deeply sub-diffractional length scales. While artificial hyperbolic metamaterials have been demonstrated, they suffer from high plasmonic losses and require complex nanofabrication, which in turn induces size-dependent limitations on optical confinement. The low-loss, mid-infrared, natural hyperbolic material hexagonal boron nitride is an attractive alternative. Here we report on three-dimensionally confined 'hyperbolic polaritons' in boron nitride nanocones that support four series (up to the seventh order) modes in two spectral bands. The resonant modes obey the predicted aspect ratio dependence and exhibit high-quality factors (Q up to 283) in the strong confinement regime (up to lambda/86). These observations assert hexagonal boron nitride as a promising platform for studying novel regimes of light-matter interactions and nanophotonic device engineering.