Implementation of Surface Plasmon Resonance Planar Waveguide Sensor System

초록

20mm ×80mm and a thickness of 1.2mm. And Cr (10nm)/Au(40nm) is deposited on fused silica substrate using bias sputtering system. Figure 1 shows the structure of SPR planar waveguide sensor chip. Prior to experiment, simulation is performed using 1D-FDM mode solver(Mode solution, Lumerical). Structure of simulation is composed of fused silica(10um)/Cr(10nm)/Au(40nm)/analyte layer, we calculate how the SPR wavelength(the spectral position of the SPR dip in the transmitted spectrum)shifts when the refractive index of analyte layer changes from 1.333 to 1.34. The simulation results for this structure are shown in figure2. When refractive index of analyte layer is 1.333, SPR wavelength becomes 607.67nm, and in case of 1.34, SPR wavelength is 617.90nm. From this result of simulation, we conclude that it is possible to implement SPR planar waveguide sensor with RIU ~ 1.37 ×10-4. For the experiment, we implement the SPR planar sensor system below. This system is compose of halogen lamp as light source, and polarizer for using TM-polarized incident light. This light is coupled to waveguide using a objective lens (×40). Output light of waveguide is directly sent to the spectrometer through another objective lens (×20). We measure four different sugar solutions with 0, 10000, 30000 and 50000 ppm using this system. Figure3 shows the result of measurement of sugar solutions. Comparing the 0ppm sugar-solution with the 50000ppm sugar solution, a SPR wavelength shift of 7.25nm is observed. So we evaluate this SPR planar waveguide sensor system has resolution with RIU~1.9310×10-4 . SPR wavelengths which are obtained from simulation and experiment are shown in figure4. Because of structural difference, result of them shows a few of difference. However, both of them show SPR wavelength tends to increase as the concentration of sugar-solution increases