Enhanced Novel Surface Plasmon Resonance Sensor And Its Application

Surface Plasmon Resonance(SPR)sensor is capable of detecting even a tiny refractive index change of the sample,with the merits of label-free,high sensitivity and real-time detection,which can be used to study the interactions between biological molecules.However,the sensing resolution of traditional SPR sensors is not high enough to measure extremely small molecules or sample solution with extremely low concentration.In order to overcome the above limitation,we proposed an enhanced novel SPR sensor in this thesis.The sensing resolution was improved by reconstructing the optical sensing system and optimizing the sensing surface.The main contents are included as below:1.Reconstructing the optical sensing system.In this thesis,phase and Goos-Hanchen(GH)shift of reflected light were measured with the novel SPR optical sensing system.Under SPR effect,the intensity of the reflected light was obviously reduced to near-to-zero,phase suffered an abrupt change,and GH shift was significantly enhanced.To extract the SPR phase signal,a parallel prism phase modulator was designed and fabricated,which could modulate the differential phase changes to p-polarized and s-polarized light.Based on the prism phase modulator,the sensing resolution of phase-interrogated SPR sensor was achieved up to 10-7 RIU.To obtain GH shift of the reflected light,a position sensor detector was utilized to measure the position of p-polarized and s-polarized light spot,respectively.The differential displacement was the GH shift that needed to be measured.The sensing resolution of GH shift-interrogated SPR sensor was achieved up to 10-7?10-8 RIU.2.Optimizing the enhanced SPR sensing surface.In this thesis,nanogroove metasurface and two-dimensional(2D)materials enhanced sensing surface were proposed and studied.For the nanogroove metasurface,surface plasmon wave was tightly confined on the top of the nanogroove ridge.The effective permittivity of the nanogroove metasurface could be tuned by changing the width and periodicity of the nanogroove structure.As a result,the wavelength of surface plasmon wave was modulated.So,by optimizing parameters of the nanogroove structure,the electric field on the sensing surface was significantly enhanced and the sensing performance was effectively improved.For 2D materials enhanced sensing surface,graphene/transition metal dichalcogenide(TMDC)/graphene/Au(Ag),TMDC/graphene/Au,graphene/Au,TDMC/Au were detailedly investigated.Through transfer matrix method and Fresnel equations,the number of graphene layers and TMDC materials could be tuned to obtain the optimized sensing surface with enhanced sensing sensitivity.Based on the nanogroove metasurface and TMDC/graphene/Au sensing surface,the resolution was achieved as high as 10-8 RIU for the glycerol solution,while limit of detection was 0.1 aM for BSA protein and 1 fM for biotin molecule.In addition,this thesis also does primary exploration of a commercialized phase-and GH shift-interrogated SPR sensor.The optical system,microfluidic system,temperature control system,valve control system,sampling system and software system are designed and fabricated respectively,which are the six main parts of the commercialized SPR sensor.At last,the six parts are integrated together to be the prototype of the commercialized SPR sensor.