Yan Zhendong, Wen Xiangmin, Gu Ping, Zhong Huang, Zhan Peng, Chen Zhuo, Wang Zhenlin
School of Physics and National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China.
Nanotechnology. 2017 Oct 31;28(47):475203. doi: 10.1088/1361-6528/aa8229.
In this paper, we report on the design and observation of double Fano resonances (DFRs) in an individual symmetry-reduced nanostructure and the induced high sensing sensitivity. Such a plasmonic nanostructure consists of a partially overlapped double-metallic nanotriangles with unequal sizes fabricated by using fast and low-cost angle-resolved nanosphere lithography. Symmetry breaking generates two narrow quadrupolar dark modes, which further enhance the coupling with fundamental bright dipole modes within the same structure, manifesting the effect of DFRs. The resonance wavelength and line shape of DFRs can be tailored by changing the degree of asymmetry as well as the size of the designed nanostructure. Based on DFRs, a high sensitivity to dielectric environment with a maximum figure of merit of 35 is measured. Due to a fast manufacturing process with high reproducibility and high structural tunability, the fabricated individual metallic nanostructure provides an opportunity for significant potential applications in localized surface plasmon resonance based single or double-wavelength sensors in the near-infrared region.
在本文中，我们报道了在单个对称性降低的纳米结构中双法诺共振（DFRs）的设计与观测以及由此产生的高传感灵敏度。这种等离子体纳米结构由通过快速且低成本的角分辨纳米球光刻技术制造的尺寸不等的部分重叠双金属纳米三角形组成。对称性破缺产生了两个窄的四极暗模式，这进一步增强了与同一结构内基本亮偶极模式的耦合，体现了双法诺共振的效应。双法诺共振的共振波长和线形可以通过改变不对称程度以及所设计纳米结构的尺寸来调整。基于双法诺共振，测量到对介电环境的高灵敏度，品质因数最大值为35。由于制造过程快速、具有高重现性和高结构可调性，所制造的单个金属纳米结构为在近红外区域基于局部表面等离子体共振的单波长或双波长传感器中的重大潜在应用提供了机会。
