Investigation of non-spherical core-shell nano particles considering the non-local effect

在这个提议中，我们关注的是非球形核壳纳米粒子光学性质的电磁模型的发展。这种粒子在调谐等离子体共振以及实现电磁场放大方面提供了很大的灵活性。由复合纳米材料构成的核壳颗粒已成为催化、传感器、光热增强和太阳能电池元件的宝贵纳米材料。如果粒子的尺寸小于10nm，那么对电磁场行为的经典描述就会变得不够充分，并且在理论中必须考虑量子力学效应，例如非局部效应和隧道效应。该项目的目标是开发和测试沉积在层状衬底上的核壳纳米粒子的非局部电磁学模型，以便我们可以研究这种结构的近场增强因子和等离子体共振位移和阻尼。我们打算对“离散源方法”进行推广，包括“广义非局部光响应”模型。我们将最低阶分布多极与“广义点匹配”技术作为多极振幅计算的基本数值格式。另一个问题是考虑放置三维谐振器的玻璃棱镜的影响。对于这个问题，可以使用我们已经采用的方法来考虑不同的“全内反射显微镜”方案。这种扩展需要实现层状结构的格林张量，以考虑核壳粒子与平面界面的完整电磁相互作用。这种广义方案可以考虑在倏逝场中沉积的具有非局域效应的核壳粒子，这可以为提高三维核壳谐振器附近的场强增强因子提供额外的机会。

In this proposal, we are concerned with development of an electromagnetic model for the optical properties of non-spherical core-shell nanoparticles. Such particles provide great flexibility in tuning plasmon resonances, as well as in realizing amplification of electromagnetic fields. Core-shell particles constructed from composite nanomaterials have emerged as valuable nanomaterials for catalysis, sensors, photothermal enhancement, and solar cell elements. If the size of the particles is smaller then 10nm classical descriptions of the behavior of the electromagnetic field become insufficient, and quantum-mechanical effects, such as the non-local and the tunneling effect have to be taken into account in the theory.The objective of this project is to develop and test a non-local electromagnetics model for core-shell nanoparticles deposited on a layered substrate such that we can investigate the near field enhancement factor and the plasmon resonance shift and damping of such structures. We intend to make a generalization of the "Discrete Sources Method" including the "Generalized Nonlocal Optical Response" model. We are going to apply lowest order distributed multipoles together with the "Generalized Point Matching" technique as a basic numerical scheme for computation of the multipole amplitudes. Another issue consists in the accounting for the influence of the glass prism the 3D resonators are deposited on. For this problem, it is possible to use the approach we have already employed to consider different "Total Internal Reflection Microscopy" schemes. This extension requires implementing the Green Tensor of the layered structure to take into account the complete electromagnetic interaction of the core-shell particle with the plane interface. This generalized scheme enables to consider core-shell particles with non-local effect deposited in an evanescent field, which can provide an additional opportunity to increase the enhancement factor of the field intensity near a 3D core-shell resonator.