| Surface plasmon resonance(SPR)technology has the characteristics of high sensitivity,wide measuring range,real-time monitoring and no marking detection,which enables it to be widely used in many fields like biochemistry,food safety,environmental engineering,especially combing with the optical fiber sensor which has the advantage of low cost,simple structure and anti-electromagnetic interference.In this thesis,we demonstrated the sensing performance of refractive index and magnetic field of the SPR sensor based on multimode-no-core-multimode(MNM)fiber structure.The main work we discussed in this thesis can be summarized as:1.The theoretical research on the SPR sensor was conducted based on the MNM fiber structure.We simulated the refractive index characteristics of the sensor in numerical,based on the theory of multilayer film transmission,and also figured out the influence of the material and thickness of metal layer and the diameter and length of no-core fiber on sensor performance.2.The refractive index sensing characteristics of SPR sensor were studied experimentally based on MNM structure.The SPR sensors based on MNM structure with different diameters and lengths were fabricated by magnetron sputtering process.The influence of the no-core fiber parameters on the refractive index sensitivity were also studied experimentally.And the SPR sensor exhibit a great sensitivity and resolution of up to 11792 nm/RIU and2.04×10-5nm,respectively.3.The magnetic field sensing characteristics of SPR sensor were studied experimentally based on MNM structure.The magnetic fluid was coated on the surface of the SPR sensor and then be packaged.Then a new type of fiber-optic magnetic field sensor based on magnetic fluid and SPR sensing was proposed.The working principle and characteristics of the sensor were analyzed in detail.The magnetic field sensing characteristics of the sensor under different magnetic field directions are experimentally studied,and the highest sensitivity can reach 7.65 nm/mT. |
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