Multi-wavelength Surface Plasmon Resonance Detection Technology Principles

Surface Plasmon Resonance (SPR) is a physical phenomenon that describes the electron oscillation of induced by evanescent wave. It is producted on the interface between the thin layer of metal and the dielectric medium, which is very sensitive to the refractive index of dielectric medium sticking on the metal surface. SPR sensor has the characteristics of high sensitivity, high speed responsibility, lower sample consumption, label-free analysis and the strong capability of anti-electromagnetism and so on. So SPR sensor has been comprehensively applied in the fields of chemical analysis, biomedicine, environmental monitor, food examination and so on.The multi-wavelength SPR sensing technology for the detection of light intensity was studied in this paper. But the intensity modulation is less applied because of the influence of the instability of light source and so on. This paper uses the optic-fiber filter to filter out two bunches of different wavelengthes and makes the difference between the refractive light intensity of them. This method reduces the polarizer and promotes the miniaturization, integration of SPR sensor.The theory SPR response curves of the central wave length respectively are 850nm and 1550nm are simulated for gas and the liquid detection, and the fitting multinomial has given. The refractive index of analyte has obtained by measure of the different value of intensity reflection rate.