Investigation Of Surface Plasmon Resonance Sensing Characteristics Metallic Periodic Nano-Structures

Surface Plasmon Resonance (SPR) sensing have advantages of real-time analysis,label-free and high sensitivity. Recently they have wide applications in chemical, medicine, material, food, environment and so on. From the perspective of international researches on SPR sensing, the metallic periodic nano-structure is one of the newest hot spots. By the modulated Local Surface Plasmon Resonance (LSPR) effect from the metallic nano-structures, special performance will be gotten, which is different from conventional SPR sensors. Based on the experience in the past, the sensing characteristics of several metallic periodic nano-structures are investigated in the thesis.Mechanism of the enhancement transmission effect of metallic periodic nano-structures based flat films is studied by Finite-Difference Time-Domain (FDTD)method and special comparing models. SPR and LSPR are proved as main factors of enhancement transmission. Models of flat film SPR sensors based on metallic periodic nano-slits and metallic periodic coterminous nano-gratings are studied. Their performances are depending on the postion of enhancement transmission peak and reflective peak, respectively. Optimized structure parameters are also proposed.Models of prism coupled SPR sensors with metallic periodic nano-structures are studied by Rigorous Coupled-wave Analysis(RCWA)and Effective Medium Theory(EMT). The simulation results show that metallic periodic nano-structures bring significant impact to conventional prism coupled SPR sensors, including the change of reflectivity curve shape and the obvious enhancement move of absorption peak. Enhancement of sensing sensitivity is gained by this way. In view of the four change factors from the adding of metallic periodic nano-structures (including the postion of absorption peak, the width of reflectivity curve, the minimum reflectivity and the enhancement move of resonance peak angle), detailed calculation and discussion are carried through.Based on the theory of SPR sensing enhancement from metallic periodic nano-structures, models of three new applied structures on prism coupled platform are studied by RCWA and EMT. The periodic embedded nano-holes metallic structure has similar LSPR effects as nano-gratings, but it has a smooth and flat sensing region, which makes it avoid many practicality problems from nano-gratings on surface. The metallic periodic trapezium-profile and inverse trapezium-profile nano-gratings have advantages to balance the enhancement move of absorption peak and quality reflectivity curve by adjust gradient of isosceles, which bring more flexibility in design of metallic periodic nano-grataing SPR sensing enhancement structures. The transmission-type SPR structure with periodic metallic-dielectric mixed gratings is formed by adding metal material into original dielectric gratings, which could improve the quality of transmission curve and the sensitivity of SPR sensing. Optimized structure parameters of these three new applied structures are proposed.Model of integrative silicon waveguide coupled SPR sensing structure with metallic periodic nano-gratings are studied by Transfer Matrix Method (TMM) and EMT. In the past, silicon has never been used in waveguide based SPR sensing for its strong absorption in visible light spectrum. By introduce metallic periodic nano- structures, this problem can be solved. The simulation result shows that SPR absorption curves will have an obvious red-shift when metallic periodic nano- structures is added. With optimized structure parameters, SPR absorption curves will move to positions far away from the strong absorption of silicon waveguide in visible light spectrum, which means that the sensing information could be complete. Besieds, the sensitivity of this sensing structure is also considerable on optimized structure parameters. This structure has potential to integrate in silicon based micro bio-chip, for the aim of"lab on chip".Research in fabrications and experiments are processed. These works include: studying of periodic nano-structures fabrication technology based on nano-imprint; designing and setting up of separate novel prism coupled SPR sensing system; fabricating of novel silicon on insulator (SOI) wafer based silicon waveguide SPR sensing structure; studying of transmission spectrum of periodic metallic nano-structures based glass flat films.