Research On Photonic Crystal Fiber Sensor Based On Surface Plasmon Resonance

Surface plasmon resonance?SPR?sensors have the advantages of high sensitivity,real-time and label-free detection,et al.Photonic Crystal Fiber?PCF?has the advantages of its structural design flexibility and unique light guiding properties.Therefore,PCF-SPR sensors have rapidly developed into a hot research direction in the field of sensing.Compared with other fiber-optic SPR sensors,the PCF-SPR sensors have extremely high sensitivity,flexible structural design and application range.However,because of their close arrangement of multiple sample channels,there is a disadvantage that the channels interfere with each other.The refractive index detection range is very narrow.In this paper,the birefringence was been introduced into the PCF-SPR sensor.At the same time,the double-circular slotted PCF-SPR sensor has been designed by optimizing the sensing performance,which greatly improves the sensitivity of the sensor probe.Simulation analysis PCF-SPR sensor filled with different refractive index samples inside the two microfluidic channels to improve the refractive index range of the filled sample,which makes the sensor performance superior.The main contents of this paper include:1.The photonic crystal fiber and surface plasmon resonance technology have been introduced in this paper,and the research background and the research status of PCF-SPR sensor have been introduced.Then,the research significance of this work have been discussed.2.The basic principle of surface plasmon resonance technology and the methods of enhancing surface plasmon resonance sensing performance are analyzed.We introduce the fillite element method applied to PCF numerical analysis,as well as the loss spectrum analysis method and sensing performance index applied to PCF-SPR sensing performance analysis.3.The principles ofHE^x₁₁mode andHE^y₁₁mode in PCF-SPR sensors with the air holes incorporating birefringence are analyzed in this work.Then the main structual parameters of PCF-SPR sensor,such as diameter of the center hole,diameter of the additional air holes,diameter of the birefringent air holes and thickness of the gold layer and the waveguide layer,et al,are discussed through simulation analysis.4.The basic structure of the PCF-SPR sensor is designed.And then,the methods of improving sensing performance are introduced.The effects of the method for adding waveguide layer and the method for introducing defect structure on the sensing performance are simulation analyzed.Finally,the structural parameters of the optimized PCF-SPR sensor are obtained.5.We make full use of the dual-channel characteristics of the designed PCF-SPR sensor,fill the upper and lower microfluidic channels with different refractive index samples to be tested.We simulate and analyze the resonance wavelengths of the upper and lower microfluidic channels,and obtain the detection range of the PCF-SPR sensor:HE^x₁₁mode is 1.33-1.36RIU,HE^y₁₁mode is 1.33-1.37RIU.Wherein,when the upper and lower microfluidic channels are filled with the same refractive index sample,theHE^x₁₁mode sensitivity is 9370 nm/RIU,and theHE^y₁₁mode sensitivity is 8940 nm/RIU.