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

• Applicant: Dr.-Ing. Thomas Wriedt
• Subject Area: Mechanical Process Engineering
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 437616189

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.

• DFG Programme: Research Grants
• International Connection: Russia
• Cooperation Partner: Professor Dr. Yuri Eremin