On the Kerr Effect and Optical Bistability of Graphene Based Spherical ZnO@Ag Core-Shell Nanocomposite

The drawback of one type of material can be modified by incorporating it with another suitable material. One of the mechanisms to enhance the properties and overcome the drawbacks of a material is by forming a core-shell nanostructure. Core–shell nanocomposites are one of the most preferable structures used to overcome the drawbacks of one material and enhance the properties of another. Graphene monolayer (GML), zinc oxide (ZnO), and silver (Ag) nanomaterials are highly recommended for optical-based applications and for enhancing the properties of other materials. Using a quasi-static approximation framework, we examine the optical response of a graphene monolayer-based ZnO@Ag spherical core-shell nanocomposite embedded in a highly compatible dielectric host matrix. The numerical study revealed that optical factors such as the dielectric function of the host medium, filling factor, volume fraction, and graphene’s Fermi energy greatly impact the nanocomposite’s local field enhancement factor, optical bistability, and hysteresis response. The graphene monolayer-wrapped ZnO@Ag spherical core-shell nanocomposite exhibits a strong nonlinear optical response in the visible spectral region. A low bistability threshold in the visible range was achieved by adjusting key parameters and utilizing Kerr-nonlinear graphene with silver as the outer shell, which enhances the nonlinear effect. These findings imply that core-shell nanostructures made with two-dimensional materials such as graphene have a unique advantage for plasmonic and optical device optimization, data storage application.