Interdisciplinary Journal

Surface Plasmon Excitation in a Spherical Nanocavity: The Hydrodynamical Drude Model

Document Type : Original Article

Author

Department of Physics, Faculty of Science, University of Zabol, Zabol, 98615-538, Iran

Abstract
We theoretically study nonlocal effects in surface plasmon excitations in a spherical dielectric nanocavity embedded in a metallic host within the framework of the hydrodynamic Drude model. An analytical expression for the surface plasmon resonance frequencies is derived, enabling a transparent interpretation of size-dependent and material-dependent plasmonic behavior beyond the local approximation. Nonlocality is shown to modify the plasmonic response, leading to a blueshift of the resonance frequencies as the nanocavity radius decreases. We further demonstrate that the background dielectric constant associated with the metal ion core plays an essential role in the excitation process. For nanocavities with dielectric constants smaller than that of the metallic background, the surface plasmon resonances shift to higher frequencies, while a redshift occurs when the cavity dielectric constant exceeds the background value. In addition, increasing the nanocavity dielectric constant enhances the influence of nonlocal effects on surface plasmon excitations. These parameters offer valuable guidance for the design of subwavelength plasmonic structures.

Graphical Abstract

Surface Plasmon Excitation in a Spherical Nanocavity: The Hydrodynamical Drude Model

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Articles in Press, Accepted Manuscript
Available Online from 24 February 2026

  • Receive Date 10 February 2026
  • Revise Date 17 February 2026
  • Accept Date 19 February 2026