Effects of Misalignment Gap of Sensing Chip on Resonant Reflectivity in Divergent Beam-based Surface Plasmon Resonance Sensor

Effects of misalignment gap of sensing chip on resonant reflectivity in divergent beam-based surface plasmon resonance sensor is theoretically studied by using the transfer-matrix method. Preliminary simulation results reveal that even when index matching oil is applied to the gap between a prism and a sensing chip, SPR reflectivity signal degrades gradually as the gap increases. The degradation appears as the increase and the shift of the minimum dip intensity and the broadening of the dip resonance curve. This might result in reduction of the SPR sensing accuracy.