Theoretical investigation of an enhanced Goos-Hänchen shift sensor based on a BlueP/TMDC/graphene hybrid

The Goos-Hänchen (GH) shift caused by blue phosphorene/transition metal dichalcogenides (BlueP/TMDCs) and graphene surface plasma resonance (SPR) in Kretschmann configuration are studied theoretically. In this structure, graphene and BlueP/TMDCs coated on Cu thin film are optimized to improve the GH shift. The highest GH shift of sensor Cu-BlueP/WS₂-graphene is 1004λ with three layers BlueP/WS₂ and a graphene monolayer. For the sensing application, the sensitivity corresponding to the optimal GH shift is 3.199×10⁶λ/RIU, which is 210.8 times higher than the traditional Cu film, 181.4 times higher than the Cu-BlueP/WS₂ (monolayer) structure, and 56.6 times higher than the Cu-graphene structure. Therefore, the SPR sensor with high GH shift can be extensively used in the fields of chemical, biomedical, and environmental monitoring.