A theoretical study of a plasmonic sensor comprising a gold nano-disk array on gold film with a SiO2 spacer
A theoretical study of a plasmonic sensor comprising a gold nano-disk array on gold film with a SiO2 spacer
复制标题
由金膜上带有 SiO2 间隔物的金纳米盘阵列组成的等离子体传感器的理论研究
DOI：
10.1088/1674-1056/28/4/044201
复制
发表时间：
2019
影响因子：
1.7
通讯作者：
Qi Yunping
中科院分区：
文献类型：
--
作者：
Wang Xiangxian;Zhu Jiankai;Tong Huan;Yang Xudong;Wu Xiaoxiong;Pang Zhiyuan;Yang Hua;Qi Yunping
提出了一种基于金复合结构的等离子体折射率传感器。这种复合结构是由一个完美的金纳米盘正方形阵列上的金膜，与二氧化硅间隔。的复合结构的反射光谱，与分析物RI在1.30至1.40的范围内，理论上使用时域有限差分法研究。入射光部分耦合到单个纳米盘的局域表面等离子体激元（LSP），部分通过光栅耦合传输到传播表面等离子体激元（PSP）。由于LSP和PSP之间的强耦合，在反射光谱的谷值处反射率几乎为零。此外，表面等离子体激元（SPPs）模式的半峰全宽（FWHM）非常窄，这有助于RI传感。获得了高达853 nm/RIU的RI灵敏度。详细研究了结构参数对RI灵敏度和传感器品质因数的影响。我们发现，传感器保持高RI的灵敏度在很大的范围内的周期和纳米盘直径。复合结构作为等离子体传感器的理论模拟结果是有前途的。因此，这种复合结构可以广泛地应用于生物和化学领域。
A plasmonic refractive index (RI) sensor with high RI sensitivity based on a gold composite structure is proposed. This composite structure is constructed from a perfect gold nano-disk square array on a gold film, with a SiO2 spacer. The reflection spectra of the composite structure, with analyte RI in the range of 1.30 to 1.40, are theoretically studied using the finite-difference time-domain method. The incident light beam is partly coupled to the localized surface plasmons (LSP) of the single nano-disks and partly transferred to the propagating surface plasmons (PSP) by grating coupling. The reflectivity is nearly zero at the valley of the reflection spectrum because of the strong coupling between LSP and PSP. Also, the full width at half maximum (FWHM) of one of the surface plasmon polaritons (SPPs) modes is very narrow, which is helpful for RI sensing. An RI sensitivity as high as 853 nm/RIU is obtained. The influence of the structure parameters on the RI sensitivity and the sensor figure of merit (FOM) are investigated in detail. We find that the sensor maintains high RI sensitivity over a large range of periods and nano-disk diameters. Results of the theoretical simulation of the composite structure as a plasmonic sensor are promising. Thus, this composite structure could be extensively applied in the fields of biology and chemistry.