Research On Photonic Crystal Fiber Localized Surface Plasmon Resonance Sensor

Photonic crystal fiber(PCF)has always been an important research topic in the field of optical fiber communication and sensing.In recent years,more and more researchers have adopted the method of combining PCF substrates with metal nanowires to achieve detection purposes by exciting Localized Surface Plasmon Resonance(LSPR).For the coupling device,the structure initially studied has disadvantages such as large volume,high cost,and difficulty in generating SPR.At present,the new coupling device of PCF has the advantages of small size and various internal air hole structure designs.Its surface and the inner wall of the air hole can be coated with various metal films and bio-sensitive films.Thus,it shows great potential for the realization of protein concentration,cell calibration and other biological detection sensors and polarization beam splitters.First of all,the principle of the LSPR phenomenon of the sensor structure,the optical properties of metal particles and films and the numerical analysis method of the PCF waveguide etc.are specifically analyzed.Secondly,a D-type PCF-LSPR sensor with a square metal nanowire array is proposed.By combining the D-type photonic crystal fiber and LSPR,the TM mode in the traditional planar waveguide is converted into a hybrid mode,and it is easy to have phase matching in a certain wavelength region.The toughness and sensitivity of the sensor are enhanced by attaching an aluminum oxide film on the metal nanowire layer.The finite element method is used to analyze the model of the structure and select the optimal parameters.Compared with the same type of sensor,the sensor has the advantages of wider detection range and sharper loss peak.Moreover,a drum-shaped sensor based on metal nanowire array is proposed.Compared with the D-type structure,this structure has a pair of symmetrical sensing planes,and the operability of the sensor structure is more flexible.The two sensing planes can respectively measure different media to be measured,which can improve detection efficiency.This paper focuses on the analysis of the dispersion characteristics of two different metal materials and proposes the phenomenon of resonance coupling degeneracy.Finally,a D-type sensor with dual-core cylindrical nanowire array is designed.Using he multi-core structure further improves the sensitivity of the sensor.The paper analyzed the influence of gold and silver metal materials on the sensitivity of the sensor.Under the condition of selecting the optimal structural parameters by the finite element method,the sensitivity of the sensor will be improved at 7000nm/RIU.