A Field-Enhancement Optical Fiber SPR Sensor Using Graphene, Molybdenum Disulfide, and Zinc Oxide

Graphene, molybdenum disulfide (MoS2), and zinc oxide (ZnO) are proposed here to enhance the evanescent field of an optical fiber surface plasmon resonance (SPR) sensor. Gold and silver are the plasmonic materials, and the fiber core material is made of polymethylmethacrylate (PMMA). A Fresnel equations-based analysis is used, and the obtained results pointed out higher values of sensitivity, figure of merit, and FWHM (full-width at half maximum) when compared to conventional SPR sensors. In despite of silver-only based SPR sensor has a better performance, oxidation occurs, and the sensor's lifetime is reduced. The addition of graphene layers leads to sensitivity values 50% higher than the conventional sensor. On the other hand, the MoS2-based sensor improves the interaction of the sensor with the bio-recognition molecules, which is attractive for biomedical applications. When ZnO was added to the silver-based sensor, a highest sensitivity, 4740.9 nm/RIU, was obtained. Graphene-based silver SPR exhibit the highest FOM values.

Automated summary

Graphene, molybdenum disulfide (MoS2), and zinc oxide (ZnO) are proposed as enhancers for the evanescent field of an optical fiber surface plasmon resonance (SPR) sensor, with gold and silver as the plasmonic materials and polymethylmethacrylate (PMMA) as the fiber core material. The results show higher sensitivity, figure of merit, and FWHM compared to conventional SPR sensors. Graphene increases sensitivity, MoS2 enhances interaction with bio-recognition molecules, and ZnO improves sensitivity the most in a silver-based sensor. Graphene-based silver SPR exhibits the highest figure of merit values.