Department of Physics, Indian Institute of Science, Bangalore 560012, India.
Nanoscale. 2018 Aug 30;10(34):16102-16106. doi: 10.1039/c8nr04666b.
Photonic manipulation with plasmonic materials is typically associated with high ohmic losses, which has triggered interest in alternative strategies based on low loss dielectric materials. Here we describe a novel dielectric nanomaterial capable of supporting strong Mie resonances from the visible to IR regimes. The fundamental block of this metamaterial is based on nanopillars in a core-shell configuration, with a large refractive index (RI) contrast between the (low RI) core and the (high RI) shell. The material showed strongly tunable optical resonances that varied from visible to near and mid IR as a function of shell thickness, core diameter and inter-pillar spacing. The numerical simulations, which are in good agreement with the experimental results, suggest the optical response to be dominated by magnetic dipole resonances. This versatile material platform is CMOS compatible, can be fabricated in a scalable manner as thin films, can act as strong scatterers in colloidal suspensions and thereby can provide several promising technological opportunities in nanophotonics.
基于等离子体材料的光子操控通常伴随着高欧姆损耗，这激发了人们对基于低损耗介电材料的替代策略的兴趣。在这里，我们描述了一种新型的介电纳米材料，它能够在可见到红外波段支持强的 Mie 共振。这种超材料的基本单元是一种核壳结构的纳米柱，核的折射率（RI）与壳的折射率（RI）之间存在较大的对比度。这种材料表现出强烈可调谐的光学共振，其范围从可见光到近红外和中红外，这取决于壳层厚度、核心直径和柱间间距。数值模拟与实验结果吻合较好，表明光学响应主要由磁偶极共振主导。这种多功能的材料平台与 CMOS 兼容，可以以薄膜的形式进行可扩展的制造，在胶体悬浮液中可以作为强散射体，从而为纳米光子学提供了几个有前景的技术机会。
