CN114609087A - Liquid refractive index measuring system and method based on Persel effect - Google Patents
Liquid refractive index measuring system and method based on Persel effect Download PDFInfo
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- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
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Abstract
The invention provides a liquid refractive index measuring system and a liquid refractive index measuring method based on a Peltier effect. The measuring system comprises a refractive index measuring probe, a one-to-two optical fiber, a laser light source, a photoelectric detector, a data collector and an output terminal, wherein a fluorescent glass thin layer is arranged on the surface of the refractive index measuring probe, and the thickness of the fluorescent glass thin layer is not more than the near field action range of the Peltier effect. The invention is based on the Possel effect, and avoids the light path design that light penetrates the liquid to be measured in the traditional refractive index measurement method. The refractive index measurement of a small amount of non-transparent liquid can be realized through the response of the fluorescence lifetime of the substance to the refractive index of the surrounding environment.
Description
Technical Field
The invention relates to the technical field of optical measurement, in particular to a liquid refractive index measurement system and a liquid refractive index measurement method based on a Peltier effect.
Background
The refractive index of liquid is a common detection index in modern scientific research and actual production life. The measurement requirement for the liquid refractive index widely exists in the industries of food, chemical engineering, medical detection, environmental monitoring, geological exploration and the like.
The measurement method of the refractive index of a liquid can be broadly classified into a geometric optical method and a wave optical method in principle. The geometric optics method measures the refractive index by accurately measuring the light deflection angle or the total reflection angle according to the law of refraction. The measuring operation is simple and convenient, and the instrument cost is lower. But is limited by the refractive index of the detection element, and the refractive index range measured by a geometric optics method is relatively limited. The wave optics law calculates the refractive index by laser phase change, mainly according to the interference principle. Generally, a laser having a high coherence is used as a light source, and a photodetector or the like is used as a detector. The precision of the measurement result is high, but the operation is complicated and the cost of the instrument is high.
The refractive index measurement by a geometric optical method and a wave optical method has certain requirements on the transmittance of the liquid to be measured under the measurement wavelength. The sample with poor transparency is difficult to realize accurate measurement of the refractive index. In addition, the measurement usually requires the volume of the liquid to be measured to be in the milliliter level, and the measurement of a trace liquid sample is difficult. For toxic and harmful or precious liquids, the traditional refractive index measurement method causes unnecessary environmental pollution and resource waste. In terms of design of the measuring instrument, the measuring instrument for the liquid refractive index can only measure the liquid refractive index at a single wavelength, and cannot provide the dispersion characteristic of the material. The measurement of the refractive index of the multi-wavelength liquid usually requires an instrument to be equipped with a plurality of switchable monochromatic light sources, so that the design of an optical path inside the instrument is complex, and the cost of the instrument is extremely high.
The above problems are widely present in various refractive index measurement methods, subject to the measurement principle of refractive index. Therefore, there is a need for improvements in existing liquid refractive index measurement methods and measurement systems.
Disclosure of Invention
The invention provides a liquid refractive index measuring system and a liquid refractive index measuring method based on the Peltier effect, aiming at least one problem existing in the existing measuring method.
In order to achieve the purpose, the invention provides a liquid refractive index measuring system which comprises a refractive index measuring probe, a one-to-two optical fiber, a laser light source, a photoelectric detector, a data collector and an output terminal, wherein a fluorescent glass thin layer is arranged on the surface of the refractive index measuring probe, and the thickness of the fluorescent glass thin layer is not more than the near-field action range of the Perssel effect; the bus end of the one-to-two optical fiber is directly connected with the refractive index measuring probe, excitation light of the laser light source enters the optical fiber through the first branch end of the one-to-two optical fiber and is transmitted to the refractive index measuring probe through the optical fiber, the fluorescence glass thin layer is excited to emit fluorescence, the fluorescence is collected through the optical fiber and is transmitted to the second branch end of the one-to-two optical fiber, the fluorescence is converted into corresponding fluorescence electrical signals through the photoelectric detector, the data collector collects the fluorescence electrical signals and electrical signals of the excitation light, and a distribution diagram of arrival time of fluorescence photons is generated; the output terminal is connected with the data collector, the fluorescence lifetime is calculated through the distribution diagram of the arrival time of the fluorescence photons, and the refractive index of the liquid to be detected is calculated through the fluorescence lifetime.
Further, the fluorescent glass thin layer comprises one or more fluorescent particles with fluorescence emission wavelength, and preferably, the fluorescent particles are quantum dots.
Furthermore, the thickness of the thin fluorescent glass layer on the surface of the refractive index measuring probe is less than 200 nanometers.
Further, the measuring system further includes an optical filter, the optical filter is located between the second branch end of the one-to-two optical fiber and the photodetector, and the optical filter is one of a long-pass filter and a band-pass filter.
Furthermore, the refractive index measuring probe is manufactured by adopting a method of fusing fluorescent glass powder and the tail fiber of the one-to-two optical fiber at high temperature.
Further, the fluorescent glass powder is selected from one or more of cesium lead chloride perovskite quantum dot glass, cesium lead bromide perovskite quantum dot glass, cesium lead iodide perovskite quantum dot glass, cesium lead chloride bromide perovskite quantum dot glass, cesium lead bromide perovskite quantum dot glass and lead sulfide quantum dot glass.
Furthermore, the one-to-two optical fiber is a multimode optical fiber, and the core diameter of the optical fiber is 100-1000 microns.
Furthermore, the core of the one-in-two optical fiber is made of quartz material, and the numerical aperture of the quartz material is 0.22-0.50.
Furthermore, the photoelectric detector is a silicon photoelectric detector, and the corresponding refractive index wavelength measurement range is 250-1100 nm; or the photoelectric detector is an indium gallium arsenide photoelectric detector, and the corresponding refractive index wavelength measurement range is 800-.
According to another aspect of the present invention, there is provided a refractive index measurement method of any one of the refractive index measurement systems described above, including: preparing a series of standard liquids with known refractive indexes, and immersing the refractive index measuring probe into the standard liquids; opening the laser light source, the photoelectric detector, the data acquisition unit and the output terminal, and measuring the fluorescence life of the fluorescent substance in the fluorescent glass thin layer; the output terminal draws a standard curve of the refractive index-fluorescence lifetime according to the fluorescence lifetime of standard liquids with different refractive indexes; preparing liquid to be measured, immersing the refractive index measuring probe into the liquid to be measured and measuring the fluorescence life of the fluorescent substance; and calculating the refractive index of the liquid to be measured according to the standard curve of the refractive index-fluorescence life.
Further, an optical filter is selected according to the measurement wavelength, and the optical filter is inserted between the second branch end of the one-to-two optical fiber and the photoelectric detector, wherein the optical filter is one of a long-pass optical filter or a band-pass optical filter.
The technical scheme of the invention has the beneficial effects that: 1. the light path design that light penetrates through liquid to be measured in the traditional refractive index measurement method is avoided. The refractive index measurement of the non-transparent liquid is realized based on the response of the fluorescence lifetime of the substance to the refractive index of its surrounding environment. 2. The measurement principle of the near-field refractive index response enables the refractive index measurement probe to have extremely low requirement on the volume of liquid, and the refractive index measurement can be completed only by microliter-level liquid at the lowest. 3. The refractive index measurement probe may contain fluorescent particles of multiple fluorescence emission wavelengths. The refractive indexes of the liquid with different wavelengths can be conveniently measured by replacing the optical filter. 4. The refractive index measuring system has wide measuring range and can cover the whole visible light region and part of near infrared region (250 nm-1700 nm). 5. The adopted semiconductor quantum dot fluorescent glass powder has wide absorption band and narrow emission band. The short-wave laser with single wavelength can excite all the fluorescent materials with emission wavelength without replacing the laser light source. 6. The refractive index measuring probe has high tolerance to acid and alkali solutions and wide measuring application range.
Drawings
FIG. 1 is a schematic structural diagram of a refractive index measurement system according to the present invention.
FIG. 2 is a schematic structural diagram of a refractive index measuring probe according to the present invention.
FIG. 3 is a fluorescence spectrum of the refractive index measuring probe under laser irradiation in example 1 of the present invention.
FIG. 4 is a refractive index-fluorescence lifetime standard curve of 635-685 nm waveband in example 1 of the present invention.
In the figure, 1 is a refractive index measuring probe, 2 is a one-to-two optical fiber, 3 is an optical filter, 4 is a photoelectric detector, 5 is a laser light source, 6 is a data acquisition device, 7 is an output terminal, 8 is a fluorescent glass thin layer, 9 is a tail fiber at the left end of the one-to-two optical fiber, F1 is a light transmission section of 415-685 nanometer bandwidth optical filter, F2 is a light transmission section of 500-540 nanometer bandwidth optical filter, and F3 is a light transmission section of 635-685 nanometer bandwidth optical filter.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
The invention provides a liquid refractive index measuring system and a liquid refractive index measuring method based on a Peltier effect. In order to make the objects, technical solutions and effects of the present invention more clear and more obvious, the present invention is described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The invention provides a liquid refractive index measuring system which comprises a refractive index measuring probe, a one-to-two optical fiber, a laser light source, a photoelectric detector, a data acquisition unit and an output terminal, wherein a fluorescent glass thin layer is arranged on the surface of the refractive index measuring probe, and the thickness of the fluorescent glass thin layer does not exceed the near-field action range of the Perssel effect; the bus end of the one-to-two optical fiber is directly connected with the refractive index measuring probe, excitation light of the laser light source enters the optical fiber through the first branch end of the one-to-two optical fiber and is transmitted to the refractive index measuring probe through the optical fiber, the fluorescence glass thin layer is excited to emit fluorescence, the fluorescence is collected through the optical fiber and is transmitted to the second branch end of the one-to-two optical fiber, the fluorescence is converted into corresponding fluorescence electrical signals through the photoelectric detector, the data collector collects the fluorescence electrical signals and electrical signals of the excitation light, and a distribution diagram of arrival time of fluorescence photons is generated; the output terminal is connected with the data collector, the fluorescence lifetime is calculated through the distribution diagram of the arrival time of the fluorescence photons, and the refractive index of the liquid to be detected is calculated through the fluorescence lifetime.
The invention is based on the Persel effect and can realize the refractive index measurement of transparent and non-transparent liquid. The Persel effect proves that the fluorescence lifetime of the fluorescent substance has a correlation with the refractive index of the near field around the fluorescent substance, and the larger the ambient refractive index is, the smaller the fluorescence lifetime of the fluorescent substance is. The standard curve of the environmental refractive index and the fluorescence lifetime of the standard fluorescent substance is known, and the refractive index of the liquid to be measured can be obtained through conversion according to the known standard curve by measuring the fluorescence lifetime of the standard substance soaked in the liquid to be measured. The fluorescent substance in the fluorescent glass thin layer in the refractive index measuring probe of the system is defined as a standard fluorescent substance, and the fluorescence lifetime of the fluorescent substance can be changed along with the refractive index of the surrounding immersion liquid.
Fig. 1 is a schematic structural diagram of the refractive index measurement system. The system comprises a refractive index measuring probe 1, a one-to-two optical fiber 2 directly connected with the measuring probe, an optional optical filter 3, a photoelectric detector 4, a laser light source 5, a data acquisition unit 6 and an output terminal 7. The bus end (left end in the figure) of one-to-two optical fiber 2 is directly connected with refractive index measuring probe 1, and the two branch ends (right end in the figure) are respectively connected with interfaces in front of laser light source 5 and photoelectric detector 4. The data acquisition unit 6, the photoelectric detector 4, the laser light source 5 and the output terminal 7 jointly form a time-related single photon counting system, namely a fluorescence lifetime measuring system, and the measuring principle and method of the system follow the principle and method of a common fluorescence lifetime measuring system. As shown in fig. 2, the surface of the pigtail 9 of the one-in-two optical fiber 2 is provided with a thin layer of fluorescent glass 8.
According to the Perssel effect, the fluorescence lifetime of a fluorescent substance is correlated with the refractive index of its surrounding near field. The thickness of the thin fluorescent glass layer 8 does not exceed the near-field range of action of the peltier effect. It should be noted that, because the probes 1 with different refractive indexes use different fluorescent materials, the thicknesses corresponding to the near-field action ranges of the fluorescent glass thin layer 8 are also different.
The exciting light emitted by the laser source 5 is transmitted to the left end refractive index measuring probe 1 through the one-to-two optical fiber 2. The fluorescence photons generated by the excitation of the fluorescent glass thin layer 8 are transmitted to the right-end photoelectric detector 4 through the one-to-two optical fiber 2. The photoelectric detector 4 converts the optical signal into an electrical signal, and the electrical signal provided by the laser light source 5 are input into the data acquisition unit 6. The data acquisition unit 6 calculates the arrival time of the fluorescence photons according to the arrival time of the electrical signals and gives a distribution map thereof. The fluorescence lifetime is finally calculated by the output terminal 7.
The measuring system avoids the light path design that light penetrates through liquid to be measured in the traditional refractive index measuring method. The refractive index measurement of the non-transparent liquid is realized based on the response of the fluorescence lifetime of the substance to the refractive index of its surrounding environment. In addition, the measurement principle of the near-field refractive index response enables the refractive index measurement probe to have extremely low requirement on the volume of liquid, and the minimum liquid with the level of microliter can be used for completing the refractive index measurement.
In some embodiments, the fluorescent glass thin layer 8 includes fluorescent particles with multiple fluorescence emission wavelengths. According to the principle of the Peltier effect, the refractive index measured by the system is the refractive index of the liquid corresponding to the emission wavelength of the fluorescent particles. Therefore, by adopting the fluorescent particles with different emission wavelengths (or wave bands), the liquid refractive indexes corresponding to different wavelengths can be measured simultaneously, and the application range of the measuring system is improved. In the preparation process of the corresponding measuring probe, the surface of the refractive index measuring probe can be coated with fluorescent glass powder with various fluorescent emission wavelengths.
Preferably, the fluorescent particles are quantum dots, and have a wide absorption band and a narrow emission band. The measuring system can excite all the fluorescent materials with the emission wavelength by adopting short-wave laser with single wavelength, and the laser light source 5 does not need to be replaced. In some embodiments, the quantum dot material is a perovskite quantum dot.
In some embodiments, the thin layer of fluorescent glass 8 on the surface of the refractive index measurement probe is less than 200 nanometers thick. So that the thickness of the thin fluorescent glass layer 8 does not exceed the near field range of action of the peltier effect.
In order to expand the test wavelength range of the measurement system and conveniently measure the corresponding refractive indexes of the liquid to be measured under the light rays with different wavelengths, the refractive index measurement probe 1 can contain fluorescent particles with various fluorescence emission wavelengths. In some embodiments, the measuring system further includes an optical filter 3, the optical filter is located between the second branch end of the one-to-two optical fiber 2 and the photodetector 4, and the optical filter 3 is one of a long-pass filter and a band-pass filter. The refractive indexes of the liquid to be measured with different wavelengths can be conveniently measured by replacing the optical filter 3.
In some embodiments, the refractive index measuring probe 1 is manufactured by fusing fluorescent glass powder to the pigtail of the one-in-two optical fiber 2 at a high temperature. The preferred fusion temperature is 800-1500 ℃. The compact glass thin layer shape can protect the quantum dots packaged inside, and is suitable for various testing environments, such as acid-base environments.
In some embodiments, the fluorescent glass powder is selected from cesium lead chloride (CsPbCl)3) Perovskite quantum dot glass, cesium lead bromide (CsPbBr)3) Perovskite quantum dot glass, cesium lead iodide (CsPbI)3) Perovskite quantum dot glass,Cesium lead chloro bromide (CsPbCl)xBr3-xX ═ 0-3) perovskite quantum dot glass, cesium lead bromine iodide (CsPbBr)xI3-xAnd x is 0-3) one or more of perovskite quantum dot glass and lead sulfide (PbS) quantum dot glass.
In some preferred embodiments, the refractive index measurement probe 1 is affixed to a probe protective cap.
In some embodiments, the splitting ratio of the one-to-two optical fiber 2 is 1: 1. so that about 50% is transmitted via a two-in-one optical fiber 2 to the right photodetector 4.
In some embodiments, the one-to-two optical fiber 2 is a multimode optical fiber, and the core diameter of the optical fiber is 100-1000 μm.
In some embodiments, the branched end of the one-to-two optical fiber 2 further includes an optical fiber interface connected to the photodetector or the laser light source 5, and the optical fiber interface is one of an FC interface and an SMA interface.
In some embodiments, the core of the one-to-two optical fiber 2 is made of quartz material and has a numerical aperture of 0.22-0.50.
In some embodiments, the photodetector 4 is a silicon photodetector, and the measurement range of the refractive index wavelength is 250-1100 nm; or the photodetector 4 is an InGaAs photodetector, and the corresponding refractive index wavelength measurement range is 800-. In other words, according to the difference of the detection bands of the photodetector 4, the measurement ranges of the refractive index corresponding to the wavelength suitable for the refractive index measurement system are 250-1100 nm and 800-1700 nm.
In some embodiments, the laser light source 5 is a pulsed laser, and more specifically, may be a violet pulsed laser.
According to another aspect of the present invention, there is provided a refractive index measurement method of any one of the refractive index measurement systems, including: preparing a series of standard liquids with known refractive indexes, and immersing a refractive index measuring probe into the standard liquids; opening a laser light source, a photoelectric detector, a data acquisition unit and an output terminal, and measuring the fluorescence life of a fluorescent substance in a fluorescent glass thin layer; the output terminal draws a standard curve of the refractive index-fluorescence lifetime according to the fluorescence lifetime of standard liquids with different refractive indexes; preparing liquid to be measured, immersing a refractive index measuring probe into the liquid to be measured, and measuring the fluorescence life of a fluorescent substance; and calculating the refractive index of the liquid to be measured according to the standard curve of the refractive index-fluorescence lifetime.
It should be noted that, because the probes 1 with different refractive indexes use different fluorescent materials and the thickness of the fluorescent glass thin layer 8 is different, the standard curve of the refractive index-fluorescence lifetime of the probes 1 with different refractive indexes has slight difference. The refractive index probe 1 only needs to use the standard refractive index solution to make a standard curve of the refractive index at a specific wavelength and the fluorescence lifetime before the first use, and then each measurement can be converted by using the standard curve obtained by the first measurement.
In some embodiments, an optical filter is selected according to the measurement wavelength, and the optical filter is inserted between the second branch end of the one-to-two optical fiber and the photodetector, and the optical filter is one of a long-pass filter and a band-pass filter. Thereby measuring the refractive index of the liquid to be measured under different wavelengths or wave bands.
Example 1
Taking cesium lead chlorine bromine (CsPbCl)xBr3-xX is 0-3 perovskite quantum dot glass powder (fluorescence peak position 433 nm), cesium lead bromide (CsPbBr)3) Perovskite quantum dot glass powder (fluorescence peak position 515 nm), cesium lead bromine iodine (CsPbBr)xI3-xAnd x is 0-3), 50 mg of each perovskite quantum dot glass powder (fluorescence peak position 658 nm) are fused on the surface of the tail fiber at the bus end of the bare one-in-two optical fiber together, and the refractive index measuring probe is prepared. Scanning electron microscopy showed that the average thickness of the thin fluorescent glass layer was about 120 nm. Two branch ends of the one-to-two optical fiber are respectively connected with a silicon photoelectric detector and a laser light source (the emission wavelength is 405 nanometers). And turning on the power supplies of the laser light source, the photoelectric detector, the data acquisition unit and the output terminal. As shown in fig. 3, the fluorescence spectrum of the refractive index measuring probe under laser irradiation.
Analytically pure perfluorohexane, perfluorooctane, methanol, diethyl ether, n-hexane, octane, cyclohexane, cyclooctane, toluene, chlorobenzene, o-dichlorobenzene, aniline, 1-chloronaphthalene each 0.5 ml were taken as standard liquids whose refractive indices were known.
An optical filter (415 and 455 nanometer bandwidth optical filter) is inserted between the second branch end of the one-in-two optical fiber and the photoelectric detector, the refractive index measuring probe is immersed in the standard liquid and the fluorescence lifetime of the standard liquid is measured, and a standard curve of the refractive index-fluorescence lifetime in the blue-violet light range is drawn.
An optical filter (500-540 nm bandwidth optical filter) is inserted between the second branch end of the one-to-two optical fiber and the photoelectric detector, the refractive index measuring probe is immersed in the standard liquid and the fluorescence lifetime of the standard liquid is measured, and a standard curve of the refractive index-fluorescence lifetime in a green light range is drawn.
An optical filter (635-685 nanometer bandwidth optical filter) is inserted between the second branch end of the one-to-two optical fiber and the photoelectric detector, the refractive index measuring probe is immersed in the standard liquid and the fluorescence lifetime of the standard liquid is measured, and a standard curve of the refractive index-fluorescence lifetime in the red light range is drawn (as shown in fig. 4).
Taking the measurement of the refractive index of water as an example: preparing non-transparent liquid to be measured (distilled water and trace methyl violet), immersing a refractive index measuring probe into the liquid to be measured, and measuring the fluorescence lifetime of the liquid to be measured. According to the standard curve of the refractive index-fluorescence lifetime, the refractive index of the liquid to be detected in the 635-685 nanometer waveband is 1.329, the refractive index of the 500-540 nanometer waveband is 1.334, and the refractive index of the 415-455 nanometer waveband is 1.341.
Example 2
150 mg of lead sulfide (PbS) quantum dot glass powder is taken and welded on the surface of the tail fiber at the left end of the bare one-in-two optical fiber. Scanning electron microscopy showed that the average thickness of the thin fluorescent glass layer was about 190 nm. The right end of the one-to-two optical fiber is respectively connected with a photoelectric detector (indium gallium arsenide photoelectric detector) and a laser light source (emission wavelength of 635 nm). And turning on the power supplies of the laser light source, the photoelectric detector, the data acquisition unit and the output terminal.
0.5 ml of each of the analytical purities as in example 1 was taken as a standard liquid whose refractive index was known.
An optical filter (1200-1350 nm bandwidth optical filter) is inserted between the second branch end of the one-to-two optical fiber and the photoelectric detector, the refractive index measuring probe is immersed in the standard liquid and the fluorescence lifetime of the standard liquid is measured, and a standard curve of the refractive index-fluorescence lifetime in the near infrared light range is drawn.
Taking the refractive index measurement of water as an example: a liquid to be measured (distilled water) is prepared, a refractive index measuring probe is immersed in the liquid to be measured, and the fluorescence lifetime thereof is measured. According to the standard curve of the refractive index-fluorescence life, the refractive index of the liquid to be detected in the 1200-1350 nm waveband is calculated to be 1.322.
Claims (11)
1. The liquid refractive index measurement system based on the Persel effect is characterized by comprising a refractive index measurement probe, a one-to-two optical fiber, a laser light source, a photoelectric detector, a data collector and an output terminal, wherein a fluorescent glass thin layer is arranged on the surface of the refractive index measurement probe, and the thickness of the fluorescent glass thin layer is not more than the near-field action range of the Persel effect; the bus end of the one-to-two optical fiber is directly connected with the refractive index measuring probe, excitation light of the laser light source enters the optical fiber through the first branch end of the one-to-two optical fiber and is transmitted to the refractive index measuring probe through the optical fiber, the fluorescence glass thin layer is excited to emit fluorescence, the fluorescence is collected through the optical fiber and is transmitted to the second branch end of the one-to-two optical fiber, the fluorescence is converted into corresponding fluorescence electrical signals through the photoelectric detector, the data collector collects the fluorescence electrical signals and electrical signals of the excitation light, and a distribution diagram of arrival time of fluorescence photons is generated; and the output terminal is connected with the data acquisition unit, the fluorescence lifetime is calculated through the distribution diagram of the arrival time of the fluorescence photons, and the refractive index of the liquid to be detected is calculated through the fluorescence lifetime.
2. The refractive index measurement system of claim 1, wherein the thin layer of fluorescent glass includes fluorescent particles of one or more fluorescent emission wavelengths.
3. The refractive index measurement system of claim 1, wherein the refractive index measurement probe has a surface with a thin layer of fluorescent glass having a thickness of less than 200 nm.
4. The refractive index measurement system of claim 1, further comprising an optical filter between the second branch end of the one-to-two optical fiber and the photodetector, the optical filter being one of a long pass filter or a band pass filter.
5. The refractive index measurement system of claim 1, wherein the refractive index measurement probe is made by fusing fluorescent glass powder to the pigtail of the one-to-two optical fiber at high temperature.
6. The refractive index measurement system of claim 5, wherein the fluorescent glass powder is selected from one or more of cesium lead chloride perovskite quantum dot glass, cesium lead bromide perovskite quantum dot glass, cesium lead iodide perovskite quantum dot glass, cesium lead chloride bromide perovskite quantum dot glass, cesium lead bromide perovskite quantum dot glass, and lead sulfide quantum dot glass.
7. The refractive index measurement system of claim 1, wherein the one-to-two optical fiber is a multimode optical fiber, and a core diameter of the optical fiber is 100-1000 μm.
8. The refractive index measurement system of claim 1, wherein the core of the one-to-two optical fiber is made of quartz and has a numerical aperture of 0.22-0.50.
9. The refractive index measurement system of claim 1, wherein the photodetector is a silicon photodetector corresponding to a refractive index wavelength measurement range of 250-1100 nm; or the photoelectric detector is an indium gallium arsenide photoelectric detector, and the corresponding refractive index wavelength measurement range is 800-.
10. A refractive index measurement method based on any one of the refractive index measurement systems of claims 1 to 9, comprising: preparing a series of standard liquids with known refractive indexes, and immersing the refractive index measurement probe into the standard liquids; opening the laser light source, the photoelectric detector, the data acquisition unit and the output terminal, and measuring the fluorescence life of the fluorescent substance in the fluorescent glass thin layer; the output terminal draws a standard curve of the refractive index-fluorescence lifetime according to the fluorescence lifetime of the fluorescent substance measured under the standard liquids with different refractive indexes; preparing liquid to be measured, immersing the refractive index measuring probe into the liquid to be measured and measuring the fluorescence life of the fluorescent substance; and calculating the refractive index of the liquid to be measured according to the standard curve of the refractive index-fluorescence lifetime.
11. The method of claim 10, wherein an optical filter is selected according to the measurement wavelength, and the optical filter is inserted between the second branch end of the one-to-two optical fiber and the photodetector, wherein the optical filter is one of a long-pass filter and a band-pass filter.
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| CN104266999A (en) * | 2014-10-20 | 2015-01-07 | 吉林大学 | Measurement instrument for refractive index of liquid based on D type plastic optical fiber probe |
| CN204556501U (en) * | 2015-05-04 | 2015-08-12 | 西京学院 | A kind of measuring device for liquid refractive index based on fiber optic interferometric |
| CN204556500U (en) * | 2015-05-04 | 2015-08-12 | 西京学院 | A kind of based on sharp light-struck device for measuring refractive index of transparent liquid |
| CN109709072A (en) * | 2018-12-29 | 2019-05-03 | 北京信息科技大学 | A kind of method for measuring liquid refractive |
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