Research On Noval Microstructured Optical Fiber Sensors Based On Surface Plasmon Resonance

Nowadays,whether it is food safety,environmental quality monitoring,or medical disease diagnosis,the applied sensors are required to have the characteristics of miniaturization,label-free,sensitive sensing,fast real-time detection,etc.Therefore,the research of miniature integratable sensors has always been a leading topic at home and abroad,and it has never been discontinued.Microstructured optical fiber(MOF)sensors based on surface plasmon resonance(SPR)occupy broad application prospects in the integration of system components,long-distance sensing and related technologies due to their small size,high sensitivity,and flexible design compared with other products.However,no mass commercial MOF sensor has yet appeared.The main difficulties are the uniformity of the metal nano-coating in the air holes and the filling of the liquid to be measured in the tiny air holes,which severely limits the development and application of the MOF sensor.Therefore,the design of the MOF structure to solve the problem of coating and liquid filling to be tested is urgently needed to be addressed.In this paper,in order to solve the main difficulties faced by MOF sensing,three structures of MOF sensors are proposed.And the finite element software COMSOL Multiphysics is used to study the three structures to analyze the working performance of the sensors under different parameters and to realize the parameter optimization of the sensors.The specific research content is as follows: First,the novel D-shaped holes MOF sensor is designed and researched.The D-shaped holes can be infinitely expanded.The optical fiber is immersed in the liquid to be measured,which effectively solves the problem of filling the liquid to be measured.Adjusting the air holes parameters and the distance from the core can achieve detection range of liquid refractive index 1.33-1.40,wavelength sensitivity can reach 10100 nm/RIU;Secondly,the dual-channel MOF sensor is researched.Using the advantages of the dual-channel structure,two liquids can be detected simultaneously,which breaks through the limitation of time-multiplexing of traditional MOF sensors,improves the efficiency of sample detection,and improves the dual-channel identification ability through the optimization of the medium layer.On this basis,a flat-throwing structure is proposed to facilitate filling of the liquid to be measured;Finally,the large-aperture groove MOF sensor is analyzed.The large-aperture groove reduces the relative distance between the coating position and the core,which is beneficial for surface plasmon excitation to achieve SPR.The influence of thickness of the gold film,the diameter of the air hole in the first layer and the polishing distance are discussed.The above research content has important scientific significance and application value to promote the practical development of high-sensitivity SPR technology in biochemical sensing technology and reduce the operational complexity in the multi-sample detection process.