Measuring device and method of transparent medium refractive index

Abstract

The invention provides a measuring device of transparent medium refractive index. The measuring device of the transparent medium refractive index comprises a semi-external-cavity laser, a cavity mirror driving device, a beat frequency combining and detecting module, a photoelectric detecting module, a sample bearing and measuring module and a signal processing and controlling system, wherein the semi-external-cavity laser outputs continuous lasers of multiple longitudinal modes and fundamental transverse modes, and comprises a gain tube and an output cavity mirror; the cavity mirror driving device is connected with the output cavity mirror, and drives the output cavity mirror to move along output laser axes in a reciprocating mode; the beat frequency combining and detecting module is arranged on a light path of the output lasers so as to obtain longitudinal mode intervals of the output lasers; the photoelectric detecting module is used for separating two longitudinal modes of the output lasers so as to form two ways of laser signals; the sample bearing and measuring module is used for bearing a to-be-detected sample and drives the to-be-detected sample to rotate around a shaft vertical to the output laser axles, and measuring the rotation angle of the to-be-tested sample; and the signal processing and controlling system is used for acquiring and processing electric signals of the beat frequency combining and detecting module and the photoelectric detecting module. The invention further provides a method for measuring the transparent medium refractive index by applying the measuring device.

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 measurement is one of the research focuses in the field of measurement technology. The application fields of refractive index measurement involve material processing, optical system design, composition detection and product identification in food, pharmaceutical, chemical and other industries, thin film detection, crystal material development, environmental monitoring and jewelry identification, etc. Especially for some demanding instrument systems, there is an urgent need for accurate measurement of the refractive index. [0003] At present, the commonly used methods for measuring the refractive index of transparent media mainly include total reflection method (critical angle method), interferometry, and minimum deflection angle method. Although the traditional refractive index measuremen...

AI Technical Summary

Problems solved by technology

Although the traditional refractive index measurement method has been continuously improved, there are few breakthroughs in principle, the accuracy is difficult to further improve, and the measurement results cannot be traced

In addition, traditional methods also have certain limitations in measuring

For example, the minimum deflection angle method needs to process the sample to be tested into a triangular prism, and the processing requirements for the sample are extremely high during high-precision measurement, and the equipment cost is high.

The 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 the refractive index of the standard sample (usually sapphire glass), the measurement range is limited, and the accuracy when used for solid medium measurement decline

The measurement of refractive index by interferometry often needs to know the thickness of the sample to be measured in advance, and the device is relatively complicated

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