Measurement device and measurement method for transparent medium refractive index

Abstract

The invention provides a device for measuring the transparent medium refractive index by utilizing a laser feedback principle. The device for measuring the transparent medium refractive index by utilizing the laser feedback principle is characterized in that laser feedback fringes generated by the displacement of a to-be-measured sample are taken as a research object; the to-be-measured sample has the wedge angle with same as that of a standard sample; when an incident plane is vertical to the laser axis displacement, because the respective thicknesses of the to-be-measured sample and the standard sample in an optical path changes, namely an optical path in a laser outer cavity changes, feedback fringes are generated in a laser output optical intensity curve. Through the relationship between the feedback fringes and the displacement amount, the refractive index of the to-be-measured sample can be obtained through calculation. The refractive index measurement range of the device provided by the invention is not restricted by a critical angle of the full-reflection principle, and moreover the to-be-measured sample can be transparent solid, liquid and gas, so the application range is wide. The invention further provides a method for measuring the transparent medium refractive index.

Description

technical field [0001] The invention relates to a measuring device and a measuring method for the refractive index of a transparent medium. Background technique [0002] Refractive index is one of the important physical parameters of materials and an important factor affecting the performance of optical systems. The application fields of refractive index measurement include the design and processing of optical components, component detection and product identification in food, pharmaceutical, chemical and other industries, thin film detection, crystal material development, environmental monitoring and jewelry identification, etc. There is also an urgent need for accurate measurement of the refractive index for some demanding instrument systems. [0003] The current refractive index measurement methods mainly include goniometric method, interferometry method, Fresnel formula method and so on. Among them, the goniometric method is to calculate the refractive index through an...

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Problems solved by technology

[0004] However, although the traditional refractive index measurement method has been continuously improved, it is difficult to further improve the accuracy. For example, the minimum deflection angle method requires extremely high processing requirements for the sample during high-precision measurement, and requires a high-precision angle measurement device with huge equipment. ,High cost

The critical angle method (total reflection method) measures the refractive index, because the condition of the critical angle needs to be met, so the refractive index of the sample to be tested must be smaller than that of the standard sample (usually sapphire glass), and the measurement range is limited.

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