Investigation of near field enhancement in clusters of plasmonic non-spherical particles considering nonlocal effects

等离子体允许在纳米尺度上操纵光，并获得强且非常受限的电磁场。这是通过局部表面等离子体共振来实现的，这是一种众所周知的现象，当受到入射电磁场时，由于纳米尺寸结构中的自由电子的集体振荡而发生在金属纳米颗粒中。等离子体纳米结构的光学响应通常由依赖于使用局部频率依赖性介电函数的经典电磁学很好地描述。如果结构尺寸小于10 nm或有一个小曲率的表面经典的麦克斯韦的理论不再是足够的，需要一个新的方法超越经典的电磁学来描述发生的物理非局部效应。这个项目的目的是开发和测试一个非局部电磁模型的等离子体纳米粒子集群的近场增强集群和近纳米粒子定位在一个平面上的调查。在离散源方法的框架下，对纳米颗粒团簇分别采用非局部流体动力学Drude模型（HDD）和广义非局部光学响应（GNOR）模型。近场在纳米颗粒或纳米颗粒系统的等离子体共振波长附近应该特别高，但是与经典电磁学相比，考虑到非局部效应，其幅度应该减小。这一研究假设将通过广泛的计算研究进行测试。

Plasmonics allows to manipulate light at the nanoscale and to obtain strong and very confined electromagnetic fields. This is achieved via a localized surface plasmon resonance, which is a well-known phenomenon that occurs in metal nanoparticles due to the collective oscillation of free electrons in nanosized structures when subjected to an incident electromagnetic field. The optical response of plasmonic nanostructures is generally well-described by classical electromagnetics relying on the use of local, frequency-dependent dielectric functions. If the structure size is less than 10 nm or there is a small curvature of the surface classical Maxwell's theory is no longer sufficient and a new approach is required going beyond classical electromagnetics to describe the occurring physical nonlocal effects. The objective of this project is to develop and test a nonlocal electromagnetics model for clusters of plasmonic nanoparticles for investigation of near field enhancement in clusters and near nanoparticles positioned on a plane surface. Both the nonlocal Hydrodynamic Drude model (HDD) and the Generalized Nonlocal Optical Response (GNOR) models will be implemented for clusters of nanoparticles in the frame of the Discrete Sources Method. The near field should especially be high near the plasmon resonance wavelength of the nanoparticle or the system of nanoparticles but its magnitude should be reduced considering nonlocal effects compared to classical electromagnetics. This research hypothesis will be tested by an extensive computational study.