https://doi.org/10.1140/epjd/s10053-025-01060-4
Regular Article – Optical Phenomena and Photonics
Geometric and dielectric modulation of nonlinear optical properties in ZnTe@Ag core–shell nanostructures: a comparative study of spherical and cylindrical inclusions
Department of Physics, Wolkite University, Wolkite, Ethiopia
Received:
27
May
2025
Accepted:
25
August
2025
Published online:
8
September
2025
This study presents a comprehensive theoretical and numerical investigation of the nonlinear optical properties of ZnTe@Ag core–shell nanostructures embedded in dielectric host matrices. Particular emphasis is placed on the effects of geometric configuration (spherical vs. cylindrical), shell thickness, and host matrix permittivity on the local field enhancement factor (LFEF) and optical bistability (OB). Analytical expressions for the internal electric fields are obtained by solving Laplace’s equation within the quasi-static approximation. The model employs a size-dependent Drude dielectric function for the metallic shell, while Kerr-type nonlinearity is introduced in the dielectric core or host medium to account for third-order optical effects. The results show that spherical nanoinclusions consistently yield stronger local field enhancement and wider bistability regions than their cylindrical counterparts, attributable to higher geometric symmetry and more efficient field confinement. The LFEF spectra exhibit two distinct resonance peaks whose positions and magnitudes can be effectively tuned by adjusting the shell thickness and host dielectric constant. Moreover, increasing the host matrix permittivity significantly reduces the OB switching thresholds and broadens the bistability window for both geometries. These findings highlight the critical roles of geometry and dielectric environment in tailoring the nonlinear optical response of core–shell nanocomposites, providing valuable design guidelines for tunable plasmonic devices, all-optical switches, and optical memory elements.
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© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
