Guo Xiangdong, Hu Hai, Liao Baoxin, Zhu Xing, Yang Xiaoxia, Dai Qing
Division of Nanophotonics, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, People's Republic of China. Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, People's Republic of China. University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China. State Key Lab for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China.
Nanotechnology. 2018 May 4;29(18):184004. doi: 10.1088/1361-6528/aab077. Epub 2018 Feb 19.
Graphene plasmon with extremely strong light confinement and tunable resonance frequency represents a promising surface-enhanced infrared absorption (SEIRA) sensing platform. However, plasmonic absorption is relatively weak (approximately 1%-9%) in monolayer graphene nanostructures, which would limit its sensitivity. Here, we theoretically propose a hybrid plasmon-metamaterial structure that can realize perfect absorption in graphene with a low carrier mobility of 1000 cm V s. This structure combines a gold reflector and a gold grating to the graphene plasmon structures, which introduce interference effect and the lightning-rod effect, respectively, and largely enhance the coupling of light to graphene. The vibration signal of trace molecules can be enhanced up to 2000-fold at the hotspot of the perfect-absorption structure, enabling the SEIRA sensing to reach the molecular level. This hybrid metal-graphene structure provides a novel path to generate high sensitivity in nanoscale molecular recognition for numerous applications.
具有极强光限制和可调谐共振频率的石墨烯等离子体激元代表了一种很有前景的表面增强红外吸收（SEIRA）传感平台。然而，单层石墨烯纳米结构中的等离子体吸收相对较弱（约1%-9%），这将限制其灵敏度。在此，我们从理论上提出了一种等离子体激元-超材料混合结构，该结构可在载流子迁移率低至1000 cm² V⁻¹ s⁻¹的石墨烯中实现完美吸收。这种结构将金反射器和金光栅与石墨烯等离子体激元结构相结合，分别引入了干涉效应和避雷针效应，并极大地增强了光与石墨烯的耦合。在完美吸收结构的热点处，痕量分子的振动信号可增强高达2×10³倍，使SEIRA传感能够达到分子水平。这种金属-石墨烯混合结构为在纳米级分子识别中产生高灵敏度以用于众多应用提供了一条新途径。
