Tunable giant Goos-Hänchen shift in Au-ReS₂-graphene heterostructure

Enhancing and flexibly controlling the Goos-Hänchen (GH) shift directly is a significant challenge. Here, we report a tunable giant GH shift in a Au-ReS₂-graphene heterostructure. The GH shift of this heterostructure demonstrates strong anisotropy and a unique "sign inversion" feature as the graphene reaches a specific thickness. Flexible control and enhancement of the GH shift to the centimeter scale can be achieved by simply rotating the crystallization direction of the heterostructure. Utilizing this feature, we designed an anisotropic refractive index sensor with a high sensitivity of 1.31 × 10⁸µm/RIU. This marks an order of magnitude improvement over previous research and introduces a rotation-dependent sensitivity adjustment feature. The tunable giant GH shift provides a promising approach for future designs of optical sensing and modulation devices.