【摘要】 以折射率的虚部表征被测介质的光吸收特性,从理论上分析了样品衰减系数对表面等离子体共振(SPR)相位差曲线的影响,并进行实验验证.结果表明:针对透明介质优化设计的SPR结构用于测量吸收介质时,相位差曲线在共振角附近的变化率随样品衰减系数的增大而减小,导致SPR相位型传感器的灵敏度退化.改变金膜厚度可有效补偿这种灵敏度的衰退.更多还原

【Abstract】 Taking sample’s absorption property into consideration and introducing an imaginary part of its refractive index,we have analyzed the dependence of the phase difference of surface plasma resonance(SPR) on the sample attenuation coefficient.It was validated experimentally.Under the optimized operating condition for transparent samples,the changing rate of the phase difference curve near the resonance angle was reduced with the enhancement of the sample’s attenuation coefficient.This degrades sensitivity of phase detection of the SPR based sensors.Nonetheless,it can be effectively compensated for by simply adjusting the thickness of Au film.更多还原