Tunable and Enhanced Goos-Hänchen Shifts in Monolayer Graphene based Metallic Grating Structure

The Goos–Hänchen (GH) effect, a lateral displacement of the reflection beam, enables rich applications in sensors and detectors. Metallic grating structures have gained great attention due to their unique properties, such as enhanced optical transmission and surface enhanced Raman scattering. Here, instead of using the dielectric grating, we demonstrate an enhanced GH shift in the structure with the metallic grating layer, monolayer graphene, dielectric spacer, and metallic substrate. We find that the amplitude of the GH shift is as high as 3616 times of the incident wavelength at the specific working frequency. This enhancement can be understood from the generation of the coupled surface plasmon polaritons between two surfaces of the dielectric space layer. Furthermore, we show efficient control of the GH shift by modulating the geometric parameters of the proposed structure and chemical potential of the monolayer graphene. Our result establishes an alternative metallic grating structure for tunable and enhanced GH shifts in graphene-based nanostructures.