Ray Debdatta, Raziman T V, Santschi Christian, Etezadi Dordaneh, Altug Hatice, Martin Olivier J F
Nanophotonics and Metrology Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland.
Bionanophotonic Systems Laboratory, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland.
Nano Lett. 2020 Dec 9;20(12):8752-8759. doi: 10.1021/acs.nanolett.0c03613. Epub 2020 Nov 18.
Hybrid metal-dielectric nanostructures have recently gained prominence because they combine strong field enhancement of plasmonic metals and the several low-loss radiation channels of dielectric resonators, which are qualities pertaining to the best of both worlds. In this work, an array of such hybrid nanoantennas is successfully fabricated over a large area and utilized for bulk refractive index sensing with a sensitivity of 208 nm/RIU. Each nanoantenna combines a Si cylinder with an Al disk, separated by a SiO spacer. Its optical response is analyzed in detail using the multipoles supported by its subparts and their mutual coupling. The nanoantenna is further modified experimentally with an undercut in the SiO region to increase the interaction of the electric field with the background medium, which augments the sensitivity to 245 nm/RIU. A detailed multipole analysis of the hybrid nanoantenna supports our experimental findings.
混合金属-电介质纳米结构最近备受关注，因为它们结合了等离子体金属的强场增强特性和介质谐振器的多个低损耗辐射通道，这两种特性堪称各擅胜场。在这项工作中，大面积成功制备了这样的混合纳米天线阵列，并将其用于体折射率传感，灵敏度达到208 nm/RIU。每个纳米天线由一个硅圆柱和一个铝盘组成，中间隔着一个SiO间隔层。利用其各子部件所支持的多极子及其相互耦合，详细分析了其光学响应。通过在SiO区域进行底切实验进一步对纳米天线进行了改进，以增强电场与背景介质的相互作用，从而将灵敏度提高到245 nm/RIU。对混合纳米天线的详细多极分析支持了我们的实验结果。
