纳米环二聚体中多重Fano共振的研究
发布时间：2018-11-27 09:50
【摘要】：金属纳米结构中局域表面等离子激元共振的现象在过去几十年中得到人们的极大关注。研究表明，金属纳米结构的光学性质取决于局域表面等离激元共振。而局域表面等离激元共振具有近场增强大、对外部环境变化敏感、可突破衍射极限等特性，在生物传感、表面增强拉曼散射、慢光传输、纳米天线、非线性增强等很多领域都有重要的应用前景。然而，随着颗粒尺寸的增大，辐射衰减极大增强，造成谱线线宽的增大，不利于上述应用性能的提高。 表面等离激元Fano共振是超辐射明态和弱辐射暗态之间的相消干涉所引起的。由于暗态的激发，可以有效抑制体系辐射衰减，形成精细的谱线，并增强近场，从而提高如生物传感质量因子等应用的性能。当体系具有多个弱辐射暗态，它们与超辐射明态的耦合可引起多重Fano共振的产生。利用多重Fano共振，可在多个波段同时调制光谱，降低辐射展宽，这对多波长传感等应用具有重要意义。本文提出暗态间的表面等离激元耦合是产生Fano共振的一种有效方法。根据等离激元杂化理论，暗态耦合将形成成键弱辐射模式和反成键弱辐射模式。当这两种杂化暗态与明态形成耦合，将在光谱中出现多重Fano共振的现象。 本文设计了一种由同心纳米环构成的二聚体共振腔结构。研究表明，，在不破坏体系对称性的条件下，纳米环之间的相互作用可直接激发起四极共振模式，两个纳米环四极模式的耦合形成了成键弱辐射杂化模式，从而引起光谱中Fano共振的出现。当上述二聚体结构中两个内环向相同的方向偏移时，即当整个结构的对称性被打破后，还可激发起反成键弱辐射模式。成键弱辐射模式和反成键弱辐射模式的形成导致了双重Fano共振的产生。
[Abstract]:The phenomenon of local surface plasmon resonance in metal nanostructures has attracted much attention in the past few decades. It is shown that the optical properties of metal nanostructures depend on the local surface isoexciton resonance. The local surface isoexciton resonance has the characteristics of large near-field enhancement, sensitive to changes in the external environment, and the ability to break through the diffraction limit. It can enhance Raman scattering on the surface, slow light transmission, nano-antenna, and so on. Nonlinear enhancement and many other fields have important application prospects. However, with the increase of particle size, the radiation attenuation is greatly enhanced, resulting in the increase of line width, which is not conducive to the improvement of the performance of the above applications. The Fano resonance of surface isotherm is caused by the interference between superradiance and weak radiation dark state. Because of the dark state excitation, the radiation attenuation of the system can be effectively suppressed, the fine spectral lines can be formed, and the near field can be enhanced, thus improving the performance of applications such as the biosensor quality factor. When the system has several weak radiation dark states, their coupling with superradiance can lead to multiple Fano resonance. The multiplex Fano resonance can modulate the spectrum at the same time in multiple wavelengths and reduce the radiation broadening, which is of great significance for the application of multi-wavelength sensing and so on. In this paper, an effective method for generating Fano resonance is presented. According to the theory of isotherm hybridization dark state coupling will form bond weak radiation mode and inverse bond weak radiation model. When the two hybrid dark states are coupled with the open state, there will be multiple Fano resonance in the spectrum. A dimer resonator structure composed of concentric nanorings is designed in this paper. The results show that the interaction between the nanometers can directly excite the quadrupole resonance mode without breaking the symmetry of the system, and the coupling of the two quadrupole modes forms the bonding weak radiation hybrid mode. Thus, Fano resonance appears in the spectrum. When the two inner loops of the dimer move in the same direction, that is, when the symmetry of the whole structure is broken, the weak radiation mode of the inverse bonding can be excited. The formation of bonding weak radiation mode and anti-bonding weak radiation mode leads to the formation of double Fano resonance.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O631
本文编号：2360287
[Abstract]:The phenomenon of local surface plasmon resonance in metal nanostructures has attracted much attention in the past few decades. It is shown that the optical properties of metal nanostructures depend on the local surface isoexciton resonance. The local surface isoexciton resonance has the characteristics of large near-field enhancement, sensitive to changes in the external environment, and the ability to break through the diffraction limit. It can enhance Raman scattering on the surface, slow light transmission, nano-antenna, and so on. Nonlinear enhancement and many other fields have important application prospects. However, with the increase of particle size, the radiation attenuation is greatly enhanced, resulting in the increase of line width, which is not conducive to the improvement of the performance of the above applications. The Fano resonance of surface isotherm is caused by the interference between superradiance and weak radiation dark state. Because of the dark state excitation, the radiation attenuation of the system can be effectively suppressed, the fine spectral lines can be formed, and the near field can be enhanced, thus improving the performance of applications such as the biosensor quality factor. When the system has several weak radiation dark states, their coupling with superradiance can lead to multiple Fano resonance. The multiplex Fano resonance can modulate the spectrum at the same time in multiple wavelengths and reduce the radiation broadening, which is of great significance for the application of multi-wavelength sensing and so on. In this paper, an effective method for generating Fano resonance is presented. According to the theory of isotherm hybridization dark state coupling will form bond weak radiation mode and inverse bond weak radiation model. When the two hybrid dark states are coupled with the open state, there will be multiple Fano resonance in the spectrum. A dimer resonator structure composed of concentric nanorings is designed in this paper. The results show that the interaction between the nanometers can directly excite the quadrupole resonance mode without breaking the symmetry of the system, and the coupling of the two quadrupole modes forms the bonding weak radiation hybrid mode. Thus, Fano resonance appears in the spectrum. When the two inner loops of the dimer move in the same direction, that is, when the symmetry of the whole structure is broken, the weak radiation mode of the inverse bonding can be excited. The formation of bonding weak radiation mode and anti-bonding weak radiation mode leads to the formation of double Fano resonance.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O631
【参考文献】
相关期刊论文 前1条
1 李志远;李家方;;金属纳米结构表面等离子体共振的调控和利用[J];科学通报;2011年32期
本文编号：2360287
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