针对表面等离子共振(SPR)传感器需要昂贵的角度转动或光谱分析装置的缺点，提出了采用双LD 进行差分光强检测折射率变化的方法。该方法基于等离子共振原理，采用两个波长对应的反射光强差来实现对介质折射率变化量的传感，设计了参考光路，以消除光源波动带来的影响。理论分析及实验表明，这种方法比单LD 光强检测方法的灵敏度提高了近一倍。由于没有使用角度检测装置及光谱仪，易于实现仪器的小型化。可通过调整入射角和采用不同光源的方法来实现不同区间的折射率测量。

Traditional surface plasmon resonance sensors have the shortcoming of needing expensive rotation or the spectrum equipment, so the method of differential detection for refractive changes with light intensity is presented and two LDs are used. This method is based on the surface plasmon resonance principle and variation of the refractive indices is measured by the optical intensity of two different wavelengths. The reference light path is designed to eliminate the fluctuation of light. Theoretical analysis and experimental results show that the sensitivity value of this method is twice as much as that of single-LD light intensity detection method, easy to implement instrument miniaturization. The angle detection device and the spectrometer are not used in the system, so the system can be potable and compact. Adjusting the incident angles and different wavelengths of light can be used to detect different range of refractive index.