Development And Sensing Characteristics Of Surface Plasmon Biosensors

Surface plasmons are collective oscillations of electrons that occur at the interface of metals and dielectric.Because of its characteristics such as breaking through the diffraction limit and near-field enhancement,it is widely used in the design of high-sensitivity sensors,and has broad prospects in environmental monitoring,biology,food safety and so on.This thesis mainly studies the preparation and sensing properties of surface plasmon sensors,and the following are the main research contents of this thesis:A grating-coupled surface plasmon sensing platform with a flat sensing surface is proposed.Miniature sensors are formed by a spiral grating in commercially available discs,combined with polymer filling and metal film coating.The proposed SPR sensing can have a size of just few micrometers and does not require complex optical collimation.The optical properties of the structure are studied by using the finite-difference time-domain method,and then the dependence of the surface plasmon mode and Fabry-Perot mode on the geometric parameters of the structure is studied by changing the geometric parameters of the structure.Finally,based on the dual-mode mechanism of the structure,it is applied to the refractive index and pressure sensing,and the refractive index sensitivity of 494 nm/RIU and the pressure sensitivity of 131.5 nm/MPa are obtained by experiments.A new method for preparing annular cavity array is proposed,which is prepared by selfassembling polystyrene nanosphere array,spin coating and nanosphere lithography.In the proposed new method,the use of nanosphere self-assembly and spin-coating method greatly reduces the fabrication cycle of annular cavity arrays and makes their substrates selectable.The optical properties of the annular cavity structure are studied by using the finite-difference time-domain method,and the regulation of the resonance wavelength of the cylindrical surface plasmon is realized by changing the geometric size of the structure.In addition,a high correlation between the refractive index and the surface plasmon resonance wavelength is achieved,and the refractive index sensitivity of 1050 nm/RIU is obtained.Finally,the detection of antigen-antibody is realized by using this annular cavity array.