A novel laser interferometric technique for measuring the variation of the refractive index with concentration and temperature is presented. The technique is based on the principle of ‘absolute scale’ accomplished with a Michelson interferometer. The linear motion of the scanning mirror allows simple extraction of the optical path change inside the Fabry–Perot interferometer. The measurement of the relative positions of the interference maxima reduces the sensitivity of the system to intensity noise and drift of the laser source. The sensitivity to the changes of the refractive index is of the order of 1 10⁻⁷ for a 20 mm optical path.

中文翻译：

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双扫描干涉技术，用于测量温度和液体折射率的浓度相关性

提出了一种测量折射率随浓度和温度变化的新型激光干涉技术。该技术基于用迈克尔逊干涉仪实现的“绝对比例”原理。扫描镜的线性运动允许简单地提取法布里-珀罗干涉仪内部的光程变化。干涉最大值的相对位置的测量降低了系统对强度噪声和激光源漂移的敏感性。对于20mm的光路，对于折射率的变化的灵敏度为1 10 ^-7数量级。