Simulation and experiment of enhanced SPR sensing in silver/graphene-modified microstructured fiber

A microstructured fiber (MSF) sensor utilizing a silver/graphene composite film is proposed and demonstrated. The sensor is fabricated by depositing a nanometer-thick silver film on the MSF and subsequently transferring a graphene film to the silver film using the liquid phase method. The proposed sensor leverages the evanescent field effect of the cladding mode in the MSF, effectively enhancing the surface plasmon resonance (SPR) effect with the assistance of the composite film, which results in a great gain in sensor sensitivity. Simulation results show that the silver/graphene bilayer structure substantially influences the mode field of the sensor and can be well applied in subsequent refractive index sensing research. The experimental findings reveal that the sensitivity of the silver-coated MSF sensor increases to 2916.8 nm/RIU following modification with graphene. The proposed sensor has the potential for applications in biomedical and environmental monitoring.