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

等离子体激元可以在纳米尺度上操控光，并获得强大且非常受限的电磁场。这是通过局域表面等离子体共振实现的，这是一种众所周知的现象，发生在金属纳米颗粒中，这是由于纳米结构中的自由电子在入射电磁场作用下的集体振荡。等离子体纳米结构的光学响应通常由依赖于局域频率相关介电函数的经典电磁学来很好地描述。如果结构尺寸小于10 nm或表面存在小曲率，经典的麦克斯韦理论就不再充分，需要一种超越经典电磁学的新方法来描述发生的物理非局域效应。本项目的目标是开发和测试等离子体纳米粒子团簇的非局域电磁模型，以研究位于平面上的团簇和近纳米粒子中的近场增强。非局域流体力学Drude模型(HDD)和广义非局域光学响应(GNOR)模型将在离散源方法的框架下用于纳米粒子团簇。特别是在纳米粒子或纳米粒子体系的等离子体激元共振波长附近，近场应该很高，但考虑到非局域效应，与经典电磁学相比，其大小应该减小。这一研究假设将通过广泛的计算研究来检验。

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.