College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, China.
Phys Chem Chem Phys. 2020 Feb 12;22(6):3604-3610. doi: 10.1039/c9cp05600a.
Plasmonic chirality has attracted more and more attention recently due to the enhanced chiroptical response and its potential applications in biosensing. Plasmonic Fano resonance arises from the interference between a dark narrow resonance and a bright broad resonance, and it provides a new paradigm to control the plasmon mode interactions. Even though a strong circular dichroism (CD) effect has been predicted in chiral nanostructures with a Fano resonance, there are few experimental studies, and the correlation between the two effects is unclear. In this research, we investigate these two effects in plasmonic heterodimer nanorods in the same spectral range. We find that the heterodimer nanostructure exhibits a Fano-like resonance and Fano-like chiroptical response, both of which are correlated with the coupling between a super-radiant electric dipole and a sub-radiant magnetic dipole mode. Due to the interference nature of the Fano resonance, the Fano-like chiroptical response exhibits distinctively sharp features in a narrow spectral range. This Fano-like chiroptical response can be explained by a modified chiral molecule theory and a simplified coupled electric-magnetic dipole model. This research may provide new insight into the physics picture of plasmonic chirality and paves the way for the development of sensitive plasmonic sensors.
由于增强的手性响应及其在生物传感中的潜在应用，等离子体手性最近引起了越来越多的关注。等离子体 Fano 共振源于暗窄共振和亮宽共振之间的干涉，它为控制等离子体模式相互作用提供了新的范例。尽管在具有 Fano 共振的手性纳米结构中已经预测到了强烈的圆二色性（CD）效应，但实验研究很少，这两种效应之间的相关性尚不清楚。在这项研究中，我们在相同的光谱范围内研究了等离子体异质二聚体纳米棒中的这两种效应。我们发现，异质二聚体纳米结构表现出类 Fano 共振和类 Fano 手性响应，这两者都与超辐射电偶极子和亚辐射磁偶极子模式之间的耦合相关。由于 Fano 共振的干涉性质，类 Fano 手性响应在较窄的光谱范围内表现出明显的尖锐特征。这种类 Fano 手性响应可以用改进的手性分子理论和简化的偶极-磁偶极子模型来解释。这项研究可能为等离子体手性的物理图像提供新的见解，并为开发灵敏的等离子体传感器铺平道路。
