Research Of Photonic Crystal Fiber Surface Plasmon Resonance Biosersor

Photonic crystal fiber?PCF?has become a research hotspot in the field of optical sensing in recent years because of its small size,single mode transmission and flexible design of cladding air holes.Surface plasmon resonance?SPR?sensing technology has high sensitivity and is widely used in many fields such as physics,chemistry,biology and so on.In this paper,several novel surface plasmon resonance?SPR?sensors based on photonic crystal fibers?PCFs?are designed.The finite element method?FEM?is used to simulate the designed sensor,study the sensing characteristics,analyze the influence of sensor structure on its performance,and provide an important theoretical basis for the manufacture of PCF-SPR sensor in the future.A single-channel PCF-SPR biosensor using TiO₂ film as the excitation layer of SPR was designed.TiO₂ film is used to enhance the detection accuracy and linear correlation of the sensor.In addition,TiO₂ film can isolate the silver film from the external environment and prevent the oxidation of the silver film.The influence of structural parameters such as silver film thickness,TiO₂ film thickness and air hole size on the performance of the sensor was analyzed by FEM.The sensor parameters are reasonably configured to improve the sensitivity and accuracy of detection.Based on that,the relationship between refractive index and resonant wavelength is analyzed.In order to enhance the anti-interference ability of sensors,a PCF-SPR biosensor with two media channels is designed.One channel is filled with the liquid of the standard concentration?The refractive index is constant?as the reference channel,and the other channel is injected into the analyte as the measurement channel.The differential measurement method is adopted and the anti-interference ability of the sensor is analyzed in detail.An anti-interference PCF-SPR sensor with dual measurement units is designed based on the dual-channel anti-interference PCF-SPR biosensor.The sensor not only has anti-interference function,but also can measure two kinds of media at the same time.The two measuring units have no influence on each other.Using one measuring unit of the sensor to detect low analyte refractive index and the other to detect high analyte refractive index,the detection range can be further expanded,and the linear correlation between the resonance wavelength of the sensor and the analyte refractive index is improved.