High-pressure gas refractive index precision measurement method

Abstract

The invention discloses a high-pressure gas refractive index precision measurement method, which adopts an optical frequency domain interference distance measurement system to precisely measure the optical path change of a high-pressure gas cavity with a fixed length before and after inflation, and detects the temperature and pressure of high-pressure gas at the same time. If the absolute length L0 of the high-pressure gas cavity before and after inflation remains unchanged, the refractive index of the high-pressure gas can be calculated by measuring the optical path L of the high-pressure gaswith the same length according to the principle that n.L0 is equal to L, namely n is equal to L / L0. The method is suitable for precise measurement of refractive indexes of all transparent materials (solid, liquid and gas) under normal pressure and high pressure.

Description

technical field [0001] The invention belongs to the field of optical technology, and relates to the measurement of the refractive index of gas, in particular to a precise measurement method of the refractive index of high-pressure gas. Background technique [0002] The refractive index of transparent materials is one of the basic parameters that characterize the optical properties of materials, and it is related to the dielectric response function of materials, which is defined as the ratio of the speed of light in vacuum to the speed of light in materials. The refractive index is usually closely related to conditions such as material composition, density, temperature, and detection wavelength, and the precise measurement of the refractive index of materials under various certain conditions is of great significance in industrial and scientific research. For example, in the experimental study of the equation of state of transparent materials, the interface particle velocity o...

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Problems solved by technology

[0004] Domestic invention patent ZL86107252 provides a measuring device for measuring the refractive index of air by interferometry, invention patent ZL90102943 provides an automatic V-prism refractometer for measuring the refractive index of transparent materials such as glass, and invention patent ZL93114899 provides a laser cavity-variable Displacement air refractive index measurement method, foreign invention patent US7130060B2 provides a refractive index measurement method for micro-interference reflection detection, US4733967 and US4685803 provide a measuring device for measuring the refractive index of gas by interferometry, these patents are based on common refractive index testing methods development, it cannot be applied to the precise measurement of the refractive index of high-pressure gas

CN20252049U provides a method for obtaining the refractive index of high-pressure fluid by measuring the light intensity before and after transmission. The biggest technical difficulty of this patent is the realization of strict parallel light paths and the analytical extraction of effective transmission light collection efficiency

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