The Signal Processing Technology In Surface Plasmon Resonance Sensing System

Surface Plasmon Resonance (SPR) sensor is widely used in chemical and biological sensing. Because the SPR sensor has many advantages, such as high sensitivity, less sample needed, fast response and so on. The traditional technique of detection of SPR sensing is calculate the refractive index based on the light amplitude, the resonance angle, the resonant wavelength, the thickness of the metal film, etc. The phase modulation technology of detection of SPR sensing is to calculate the refractive index based on the phase change information between the interference signals of p-polarization and the reference signals of s-polarization. The sensor resolution is much higher than other modulation technology. So the phase modulation of SPR sensors has received extensive attention and in-depth research in various fields.The purpose of this study is to achieve high sensitivity, resolution of phase measurement based on SPR sensing technology by optimizing the signal processing technology. Use the differential phase SPR biosensor based on Mach-Zehnder configuration, the SPR phase can be extracted by comparing the phase difference between the interference signals of p-polarization and the reference signals of s-polarization, which are Receiving by computer. According to the signal processing knowledge, the phase difference of 2-path signals can be selecting, processing and analyzing at the same time. For a time, the phase difference of ups and downs is 0.006°, and the sensitivity limit is 4.7×10-7RIU.The core contents include three parts. First, the results of simulation analysis of phase SPR sensing principle, resolution and sensitivity. Second, build the system of phase SPR sensing and design the signal processing technology. Finally, do the experiment of measure the refractive index and verify the performance of the system. The paper proposed a new algorithm of phase signal processing (select the interference signal, pretreat the interference signal, lock the selection of the interference signal and process the interference signal accurately). The new algorithm improves the measurement resolution of the phase difference, and the phase drift has been suppressed. Achieve a high sensitivity SPR sensor in measuring the rate of refractive index.