Study On The Characterization Of Fiber Sensing From Surface Plasmonic Resonance

Surface plasmon resonance(SPR)fiber optic sensing technology is a new method that combines plasma and fiber for optical transmission and detection at the nanoscale.SPR fiber optic sensor is a key device for markerless real-time detection,in addition to its small size,sensitive response,and immunity to electromagnetic interference,the evanescent field is also susceptible to environmental refractive index change and can convert the information of refractive index change into wavelength change,so it is widely used in gas or liquid detection,it has been rapidly developed in recent years and is one of the current research hotspots.Meanwhile,with the development of micro and nano processing technology,the existing sensors are developing towards high performance such as high sensitivity and multiparameter detection.Based on this,this paper presents an innovative combination of different optical fiber structures,two-dimensional materials,and sensing materials to improve sensor performance.The main studies are as follows:1.In order to improve the sensitivity of the sensor,a plasma optical fiber sensor based on a graphene metal nanowire array is proposed.By depositing graphene-metal nanowire arrays on the D-type side casting surface of the fiber,strong local surface plasmon resonance is generated to improve the refractive index sensitivity of the sensor.This design analyzes the dispersion relationship between the plasma mode and the core mode of the sensor,and also investigates the influence of its structure parameters on sensor performance,and finally analyzes and compares the sensitivity of the sensor with three different structures(gold film structure,graphene-gold film-graphene structure,and graphene-metal nanowire array structure).The results show that when the refractive index varies from 1.33 to 1.40,the maximum sensitivity is 7383.79 nm/RIU,and the average sensitivity is 4136 nm/RIU.2.In order to solve the limitation of single-parameter detection of the sensor,a plasma fiber sensor with integrated detection of multiple parameters is proposed.By introducing gold film-temperature sensitive medium(PDMS)and gold film-magnetic fluid(MF)in the air holes on both sides of the photonic crystal fiber core to detect temperature and magnetic field,respectively,and at the same time,to improve the sensor sensitivity,the D-type side throw surface is coated with gold film-graphene composite,and finally,the influence of key parameters of the sensor on its performance is investigated.The results show that the maximum sensitivity of the sensor can reach 76000 nm/RIU when the refractive index detection range is 1.36～1.43,the magnetic field strength detection range is 20～550Oe and the temperature detection range is 5～55°C,while the sensitivity of magnetic field strength and temperature are 164.06 pm/Oe and-5001.31 pm/°C,respectively.3.In order to solve the limitation of sensor detection range,an ultra-wide range high sensitivity plasmonic fiber sensor based on gold nano-group arrays is proposed.By depositing multiple metal nanowires as a group of gold nano-group arrangements on the Dtype side casting surface of the fiber,the local surface plasmon resonance generated by it is used to improve the refractive index detection range and sensitivity of the sensor.Finally,the dispersion relationship of the sensor is analyzed and the influence of key sensor parameters on its performance is investigated.The results show that the designed sensor can reach the refractive index detection range of 1.16～1.37 and its maximum wavelength sensitivity can reach 10659.1 nm/RIU.finally,a reasonable experimental scheme is proposed for future experimental validation work,from the fabrication process of optical fiber and photonic crystal fiber to the SPR fiber sensor sensing system.