Optical response of dielectric&metal-core/metal-shell nanoparticles: Near electromagnetic field and resonance frequencies

• O. Rocha-Rocha ^[1] ; S. Gastélum-Acuña ^[2] ; M. Flores-Acosta ^[1] ; R. García-Llamas ^[1]
  1. [1] Universidad de Sonora

     Universidad de Sonora

     México

     
  2. [2] Universidad Popular del Cesar

     Universidad Popular del Cesar

     Colombia

     
• Localización: Revista Mexicana de Física, ISSN-e 0035-001X, Vol. 68, Nº. 3, 2022, págs. 453-461
• Idioma: inglés
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• Resumen

  • 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.