Abstract

ROCHA-ROCHA, O.; GASTELUM-ACUNA, S.; FLORES-ACOSTA, M.  and  GARCIA-LLAMAS, R.. Optical response of dielectric&metal-core/metal-shell nanoparticles: Near electromagnetic field and resonance frequencies. Rev. mex. fis. [online]. 2022, vol.68, n.3, e031302.  Epub Apr 14, 2023. ISSN 0035-001X.  https://doi.org/10.31349/revmexfis.68.031302.

We study the diffraction of a monochromatic electromagnetic plane wave by a dielectric&metal-core/metal-shell nanoparticle surrounded by a dielectric medium. This problem was solved by using generalized Mie’s theory and both the scattering cross section and the square module of the electric field were calculated as a function of shell thickness. Numerically, the first particles studied were gold-core/silver-shell nanoparticles and their inverse configuration. The gold-core/silver-shell particle presented more variation of their optical properties. The second particles were vacuum-core/metal-shell surrounded by vacuum, symmetric configurations. In this case, the dispersive Drude dielectric function for the metal was used, and a comparative study between the positions of the resonance frequencies obtained from quasi-static limit and electrodynamic theory was performed. Thus, consequently the formula obtained from the quasi-static limit can be used to calculate the positions of the resonance frequencies instead of the electrodynamic theory, when the external radius is smaller than 20 nm.

Keywords : Core/shell nanoparticle; scattering cross section; quasi-static limit; resonance frequencies.

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