Resolving the Refractive Indices of Transparent and Translucent Liquids from the Spacings, Spatial Frequencies, and Directions of Interference Fringes
Qingli Jing,
Jiajian Wang,
Jianglong Lei,
Qi Wang,
Jialing Chen,
Jun Liu,
Minglin Zhao,
Jiantai Dou,
Yuanxiang Wang,
Youyou Hu
Affiliations
Qingli Jing
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Jiajian Wang
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Jianglong Lei
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Qi Wang
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Jialing Chen
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Jun Liu
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Minglin Zhao
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Jiantai Dou
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Yuanxiang Wang
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
Youyou Hu
Department of Optoelectronic Information Science and Engineering, School of Science, Jiangsu University of Science and Technology, Zhenjiang 212100, China
In this work, we present a novel approach to resolve the refractive indices of transparent and translucent liquids from straight interference fringes. The optical path difference between the two arms of the Mach–Zehnder interferometer is first derived by assuming a reference plane wave interfering with a plane wave passing through a rectangular cuvette. The analytic expressions for the liquid refractive indices are then deduced, describing how the refractive index is related to the fringe spacings, spatial frequencies, and directions. The structure coefficients in the above formulas are determined from the fringe spacings and directions of the interference patterns of the empty cuvette and the cuvette filled with a liquid of a known refractive index. The NaCl solution and Coca Cola are adopted as the test examples to show experimentally the validity of the proposed method. There is good agreement between the refractive indices obtained from the fringe spacings and direction of a single interference pattern. The sensitivity and resolution of this method are dependent on the structure of the experimental systems and thus can be adjusted in a controlled manner. The proposed method is simple to implement and can be easily extended to other high precision optical interferometer systems.