Dynamically adjustable-induced THz circular dichroism and biosensing application of symmetric silicon-graphene-metal composite nanostructures.
Dynamically adjustable-induced THz circular dichroism and biosensing application of symmetric silicon-graphene-metal composite nanostructures.
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DOI：
10.1364/oe.419614
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发表时间：
2021-03
期刊：
影响因子：
3.8
通讯作者：
Yongkai Wang;Qijing Wang;Qianying Wang;Yingying Wang;Zhiduo Li;Xiang Lan;Jun Dong;Wei Gao
中科院分区：
文献类型：
--
作者：
Yongkai Wang;Qijing Wang;Qianying Wang;Yingying Wang;Zhiduo Li;Xiang Lan;Jun Dong;Wei Gao
诱导圆二色谱(ICD)通过手性分子和非手性金属纳米结构与定域表面等离子激元(LSP)的耦合，被用来检测生物分子的构象。然而，这个ICD总是很弱，不能动态调整。在这里，我们将介电和石墨烯纳米结构放置在金属衬底上，以限制更多的光能，并获得动态可调的性能。从理论上研究了非手性硅纳米棒与石墨烯带(ASMG)组成的复合纳米结构阵列。两个强ICD信号出现在太赫兹区域。ASMG的近场磁场分布表明，两个较强的ICD信号分别来自金属-衬底上的表面等离子体共振(SPP)和石墨烯纳米结构中的LSP。ICD信号强烈依赖于ASMG的几何参数，并且只需改变石墨烯-带的费米能级就可以动态调节。此外，左手ASMG和右手ASMG可用于识别不同手性的手性分子溶液。在太赫兹波段，手性分子溶液的最大增强倍数可达3500倍。这些结果有助于设计动态可调的THz手性传感器，促进其在生物监测和不对称催化中的应用。
Induced circular dichroism (ICD) has been used to detect biomolecular conformations through the coupling between chiral molecules and achiral metal nanostructures with the localized surface plasmon (LSP). However, this ICD is always weak and cannot be dynamically adjusted. Here, we put dielectric and graphene nanostructures on a metal-substrate for restricting more light energies and obtaining dynamic adjustable performance. A composite nanostructure array composed of achiral silicon-nanorods on a metal-substrate and graphene-ribbons (ASMG) is theoretically investigated. Two strong ICD signals appear in the THz region. Near-field magnetic distributions of ASMG reveal that the two strong ICD signals are mainly due to the surface plasmon resonances (SPPs) on the metal-substrate and LSP in the graphene nanostructures, respectively. The ICD signals strongly depend on the geometric parameters of ASMG and are dynamically adjusted by just changing the Fermi levels of graphene-ribbons. In addition, left-handed ASMG and right-handed ASMG can be used to identify the chiral molecular solutions with different chiralities. The maximum enhancement factor of the chiral molecular solutions could reach up to 3500 times in the THz region. These results can help to design dynamically adjustable THz chiral sensors and promote their application in biological monitoring and asymmetric catalysis.