High Sensitivity Localized Surface Plasmon Resonance Sensing Using a Double Split NanoRing Cavity
High Sensitivity Localized Surface Plasmon Resonance Sensing Using a Double Split NanoRing Cavity
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DOI：
10.1021/jp209754m
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发表时间：
2011-11
影响因子：
3.7
通讯作者：
Shao-Ding Liu;Zhi Yang;Ruiping Liu;Xiuyan Li
中科院分区：
文献类型：
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作者：
Shao-Ding Liu;Zhi Yang;Ruiping Liu;Xiuyan Li
在实际应用中，金属纳米结构的生物传感常常受到大辐射阻尼引起的等离子体共振线宽大的困扰。为了抑制辐射阻尼，设计了双缝纳米环腔。单间隙分裂纳米环的超辐射四极模式与双间隙分裂纳米环的次辐射四极模式之间的耦合导致模态能量分裂为成键和反键四极-四极模式。辐射阻尼被有效地抑制，导致成键和反键四极-四极模式的线宽都很窄。计算结果表明，采用金双裂纳米环腔，获得了超过1200 nm/RIU的体折射率灵敏度，近红外的优值超过8.5。大的腔体体积和均匀的腔内电场使双分裂纳米环腔成为表面增强分子传感的良好平台。
Practical implementations of biosensing with metallic nanostructures often suffer from the large line width of the plasmon resonances induced by large radiative damping. A double split nanoring cavity is designed to suppress the radiative damping. The coupling between the superradiant quadrupole mode of a split nanoring with one gap and the subradiant quadrupole mode of a split nanoring with two gaps leads to splitting of the modal energies into bonding and antibonding quadrupole–quadrupole modes. The radiative damping is suppressed effectively, leading to a narrow line width for both bonding and antibonding quadrupole–quadrupole modes. Calculation results show that bulk refractive index sensitivities exceeding 1200 nm/RIU with a figure of merit exceeding 8.5 in the near-infrared are obtained with a Au double split nanoring cavity. The large cavity volumes and uniform electric fields inside the cavity make the double split nanoring cavity a good platform for surface-enhanced molecular sensing.