Research On Sensor Technology Based On SPR Using Wavelength And Angle Modulation

Surface plasmon resonance(SPR) is a physical optical phenomenon under total internal reflection. When the evanescent wave vector and surface plasmon wave vector are equal, the energy of evanescent wave transfers to surface Plasmon wave.SPR sensing technique has been rapidly developed and used in a wide range of applications including chemical analysis, biosensing, drug development, environmental monitoring, food safety and medical diagnostics. In this paper, we first study the basic physical principles of SPR based on detecting resonance shifts in angle, wavelength, and phase, respectively, and then analyze the sensitivity and dynamic range of kinds of SPR sensors.When SPR phenomenon occurs, there are the best resonance angle and resonance wavelength, named the best resonance dip(θ0,λ0)at which the total energy of incident light transfers to the surface Plasmon wave and the phase curve of SPR has the steepest part. The sensitivity at the steepest part is highest. The change of the best resonance angle is proportional to the change of refractive index of sample on the sensor film.To overcome the traditional SPR sensor’s problems such as narrow dynamic range and low sensitivity, we proposed a novel intensity-sensitive SPR technology based on wavelength and angle simultaneous interrogation. The wide dynamic range and high sensitivity capability of our SPR technology are experimentally demonstrated by detecting the refractive index value of different alcohol-water mixtures. In comparison with the traditional wavelength or angle interrogation SPR technology, our technology greatly improved the detection sensitivity and dynamic range.We also present another novel SPR technology with both a wide dynamic detection range and high sensitivity based on wavelength-scanning is presented. The dynamic detection range and sensitivity of SPR sensor are theoretically analyzed respectively, and the principle setup is built. In order to testing the effectiveness of our SPR sensor, we detect alcohol-water solutions with different concentration. Experimental results show that the sensitivity of our SPR sensor is 3.1×10-5 RIU with a refractive index range of1.30-1.38.Finally, we propose a polarization interferometry based on the wavelength and angle simultaneous interrogation phase-sensitive SPR technology, and its numeral simulation analysis was done. The wavelength and angle simultaneous interrogation approach can further improve the detection sensitivity and dynamic range.