介绍了表面等离子体共振(SPR)传感器的工作原理，设计了一套基于波长检测型Kretschmann结构的SPR传感测试系统。通过固定入射光角度，以波长为变量，测定了10种不同浓度的乙醇水溶液折射率与共振波长之间的对应关系。实验结果表明，共振波长随着样品折射率的增大而逐渐向长波长方向偏移，且两者之间呈现良好的线性关系。通过对共振光谱的分析，实现对未知溶液折射率或者浓度的测定。整个传感器系统具有结构紧凑、操作简单、实时检测和测量准确等优点。

The principle of surface plasmon resonance (SPR) sensor is introduced. A SPR measurement system with Kretschmann configuration is designed based on wavelength modulation technology. The relationship between refractive index and resonance wavelength for ten different concentrations of alcohol solution is measured by detecting the light intensity reflectivities with fixing the incident angle while changing the wavelength. Experimental results show that the resonance wavelength increases with increasing sample refractive index, exhibiting good linearity. The SPR sensor can realize the measurement of refractive index or concentration of unknown solution by analyzing the resonant spectrum. The SPR sensor demonstrated here is featured with compact structure, simple operation, accurate and real time measurement.