Study On Surface Plasmon Resonance Sensor Based On The Metallic Nano-structure

The sensing technology based on surface plasmon resonance has wide applicationprospect in biomedical, food safety, environment detection, etc, as a result of itsparticular advantages of high sensitivity, good anti-interference and the dection withreal-time and non-destructive. In this paper, further studies are conducted about theSPR sensor based on metallic nano-structure, and relationship between resonantenhancemnet and periodic arrays of metal nanoparticles is esploited. Further more, thedesigned metallic nanostructure is applied to the SPR sensor, and its detectionsensitivity and resolution are studied.The field enhancement properties and SPR effects of the periodic silvernanoparticle arrays are studied by using finite difference time domain (FDTD)method,combined with surface plasmon optics and electromagnetic field theory. Theresonance enhanced characteristics of spherical, cylinderical and rectangularnanoparticle arrays are firstly studied, as well as its effects on enhancing theabsorption of substrate. The impact of the size, shape and the array period of metalnanostructures on the resonance enhanced characteristics is discussed in detail. Andon this basis, a diamond shaped silver nanoparticle arrays structure which has strongerSPR effects is designed. This array structure has stronger resonance enhancementeffect as well as the absorption enhancement effect of the substrate, and the maximumabsorption enhancement factor reaches1.51, the maximum absorption enhancementratio is8.2.Based on the above studies, the application of SPR sensor based on the diamondshaped nanoparticles array in the refractive index detection is discussed. In therefractive index range(n=1~1.5), the change of the resonance wavelength and the lightintensity reflectivity is approximately linear with changes of the refractive index.Through the analysis of the impact of the nanostructure shape, the substrate and thelight incidence angle on the dectection sensitivity of sensor, and with the furtheroptimization, the maximum detection sensitivity837nm/RIU is obtained, thedetection resolution is close to10-3RIU, the detection sensitivity of light intensityreflectivity is0.96AU/RIU. The satisfactory results could be achieved in cases thesensor is used to detect different types of solution. Finally, the designed SPR sensordetection system based on the diamond nanoparticles array is introduced.The study in this paper has important reference value and significance for thedesign of higher sensitivity SPR sensors, and the application of SPR sensor in organs of the human body detection, food safety and environmental protection monitoringetc.