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提出了一种可抑制角漂移的表面等离子体传感器结构,并结合相位测量设计了相应的气体折射率测量系统。分析表明激光入射角、金膜厚度以及反射光p、s分量的相位差与气体折射率之间的固有非线性是影响相位响应度与折射率测量精度的主要因素。计算表明所提出的自适应结构将角漂移引起的误差降低了一个数量级并很大程度提高了测量灵敏度。同时分析设计了金膜厚度参数,并评估了反射光p、s分量的相位差与气体折射率之间固有非线性带来的误差。应用于空气折射率的测量比对实验显示其测量精度达到了10-6量级。
A structure of surface plasmon sensor that can restrain angular drift is proposed. The gas refractive index measurement system is designed based on phase measurement. The analysis shows that the inherent nonlinearity between the laser incident angle, the gold film thickness and the phase difference between the p and s components of the reflected light and the gas refractive index is the main factor that affects the phase responsivity and refractive index measurement accuracy. Calculations show that the proposed adaptive structure reduces the error caused by angular drift by an order of magnitude and greatly improves the measurement sensitivity. At the same time, the parameters of the gold film thickness were analyzed and designed, and the errors caused by the inherent nonlinearity between the phase difference of the p and s components of the reflected light and the refractive index of the gas were evaluated. Used in the measurement of air refractive index comparison test showed that the measurement accuracy reached 10-6 orders of magnitude.