CN210517316U

CN210517316U - Nile red dye laser for acid detection

Info

Publication number: CN210517316U
Application number: CN201921830852.8U
Authority: CN
Inventors: 方昱玮; 程军杰; 王声波; 董天浩; 顾春; 许立新
Original assignee: University of Science and Technology of China USTC
Current assignee: University of Science and Technology of China USTC
Priority date: 2019-10-29
Filing date: 2019-10-29
Publication date: 2020-05-12
Anticipated expiration: 2029-10-29

Abstract

The utility model provides a nile red dye laser for acidity detects comprises laser pumping source, optical system and dyestuff laser cavity, and laser source is Nd: YAG solid laser, the light that the pumping source sent shines on the energy governing system that comprises half-wave plate and polaroid through the frequency doubling crystal, first total reflection mirror and second total reflection mirror are same laser dichroic mirror, the pump light of 1064nm is transmitted away, 532 nm's frequency doubling light then reflects back and is regarded as the direct pump light of dye laser resonant cavity, focusing lens and aperture diaphragm are as the shaping system of incident pump light, the dye laser resonant cavity includes plane dichroic mirror, the quartz cuvette that is equipped with the nile red solution and output coupling mirror, plane dichroic mirror is located aperture diaphragm rear 10mm, the quartz cuvette is located plane dichroic mirror rear 15mm, output coupling mirror 10mm apart from the rear. Has wide application prospect in the fields of biochemical detection, laser chemistry, laser spectrum technology and the like.

Description

Nile red dye laser for acid detection

Technical Field

The utility model relates to a dye laser specifically is a dye laser of nile red for acidity detection.

Background

Laser has been widely used in the fields of laser communication, spectroscopy, optical imaging, biochemical detection and the like for more than 50 years due to the advantages of good coherence, good directivity, high brightness and the like. In recent years, organic dye lasers have attracted attention and research of many scholars and scientists due to their advantages of simple structure, convenient operation, various materials, wide fluorescence spectrum, etc. In the research of dye lasers, dyes that can be used as laser gain media are one of the hot spots of research. Whether an organic dye can function as a laser gain medium depends on its energy level structure and chemical properties. The most commonly used laser dyes at present are coumarin, xanthine, pyrrolidone and the like, and the dyes have high fluorescence emission intensity and are one of the necessary conditions for obtaining laser gain.

In recent years, optical systems for sensing or detection are becoming more popular, with detection against acid rain being one of the major concerns of scientists. Acid rain is a dangerous global pollutant whose harmfulness is self-evident. Scientists have great enthusiasm for detecting the content of sulfuric acid or nitric acid in acid rain in real time. The most widely used at present is an acidic indicator, which has the advantages of lightness and portability. However, the acid indicator is susceptible to other interferents such as smoke, acetone, gasoline and the like, and the detection result is inaccurate. In addition, the principle of the acid indicator is based on fluorescence detection, the spectral range is wide, and the sensitivity of the detection result is not high.

Nile red is a laser dye of a benzoxazine family, and has excellent solvatochromic characteristics, namely high fluorescence intensity in a large amount of organic solvents and hydrophobic lipids, and complete fluorescence quenching in water or solvents with lower models. The good solvatochromic characteristic means that Nile red can be used as a fluorescent hydrophobic probe and widely applied to various photochemical detection occasions.

SUMMERY OF THE UTILITY MODEL

The utility model aims to design a nile red dye laser for acid detection by adopting a novel laser dye-nile red.

The utility model adopts the technical proposal that: a Nile red dye laser for acidity detection comprises a laser pumping source, an optical system and a dye laser resonant cavity. Wherein the laser light source 1 is Nd: YAG solid laser, the light emitted by the pump source is irradiated on the energy adjusting system composed of a half-wave plate 3 and a polaroid 4 through a frequency doubling crystal 2. The first total reflection mirror 5 and the second total reflection mirror 6 are the same laser dichroic mirror, and transmit out the pump light with 1064nm, and reflect the frequency doubling light with 532nm back to be used as the direct pump light of the dye laser resonant cavity. The focusing lens 7 and the aperture stop 8 serve as a shaping system for the incident pump light. The dye laser resonator comprises a planar dichroic mirror 9, a quartz cuvette 10 filled with a nile red solution, and an output coupling mirror 11. The plane dichroic mirror 9 is located 10mm behind the small-hole diaphragm 8, the quartz cuvette 10 is located 15mm behind the plane dichroic mirror 9, and the distance from the rear output coupling mirror is 10 mm. Finally, the output laser is connected to the spectrometer 12 for analysis.

Wherein, the fluorescence/laser material used in the experiment is Nile red, and the molecular formula is C₂₀H₁₈N₂O₂The organic solvent is ethanol (C)₂H₅OH), the net content GC of ethanol is more than or equal to 99.5 percent. The concentration value of nile red in ethanol solvent was 60 μ g/mL.

YAG solid laser, wherein the laser source 1 is Nd, and the output laser wavelength is 1064 nm; the frequency doubling crystal 2 is a potassium titanyl phosphate (KTP) crystal.

The first total reflection mirror 5 and the second total reflection mirror 6 are the same laser dichroic mirror, and have high transmission (T > 99%) at 1064nm and high reflection (R > 99%) at 532nm through surface coating.

Wherein, the focusing lens 7 is common K9 glass, and the focal length is 100 mm; the aperture diaphragm 8 has a light-passing opening of 5 mm.

The laser resonant cavity consists of a plane dichroic mirror 9, a quartz cuvette 10 filled with a nile red solution and an output coupling mirror 11. The coated planar dichroic mirror 9 is highly transmissive at 532nm (T90%) and highly reflective at 560nm to 700nm (R90%). The quartz cuvette 10 contains a Nile red organic solution for acid detection, the used glass material is common optical quartz glass, the optical path is 5mm, and the transmissivity of the front optical surface and the rear optical surface in a visible light range exceeds 99.5%. The surface of the output coupling mirror 11 is coated, and the reflectivity is 85% in the range of 400nm to 700 nm.

Wherein, the acidic environment provider used in the experiment is sulfuric acid (H) which is a representative of non-volatile acid₂SO₄) The sulfuric acid/ethanol solution with different concentrations is mixed with the Nile red solution, and the acidity of the solution system can be continuously changed.

In order to enlarge the detection range of acidity, a method of connecting cuvettes in series can be adopted, and the specific implementation method is as follows: the single cuvette was replaced with a double-layered quartz cuvette in series, in which the front chamber contained 60. mu.g/mL of rhodamine 6G in ethanol and the back chamber contained 60. mu.g/mL of Nile Red in ethanol. The aim of expanding the acidity detection range is achieved by measuring the laser spectrum of the sulfuric acid/ethanol solution with different concentrations of 0ppm to 500 ppm.

The utility model has the advantages of it is following:

1. the dye laser system for acid detection is prepared by utilizing the solvation color development characteristic of the Nile red organic solution.

2. The traditional fluorescence detection technology is abandoned, and the laser spectrum detection technology is adopted, so that the detection sensitivity is higher, and the result is more accurate.

3. In order to eliminate the problem of time instability in the system and expand the detection range, a novel tandem cuvette structure is adopted, a mixed dye laser system of a Nile red/ethanol solution and a rhodamine/ethanol solution is utilized, so that the acidity detection range is enlarged, and the detection under low acid concentration can be obtained through the laser peak position and the proportion laser double-peak relative intensity.

4. The whole structure is simple, the operation is easy, and the cost is lower.

Drawings

FIG. 1 is a light path diagram of a Nile Red dye laser for achieving acid detection in the present invention;

FIG. 2 is the output laser spectra of the 60 μ g/mL nile red ethanol solution of example 1 in the presence of different concentrations of sulfuric acid;

FIG. 3 is the output laser spectra of the 200 μ g/mL nile red ethanol solution of example 2 in the presence of different concentrations of sulfuric acid;

FIG. 4 is the wavelength instability over time in different acidic environments of example 2;

FIG. 5 is a light path diagram of the serial cuvette method for detecting acidity in example 4 using Nile Red ethanol solution and rhodamine ethanol solution;

FIG. 6 is a graph showing a detection output spectrum in a highly acidic environment (10ppm to 500ppm) in example 4;

FIG. 7 is a graph showing a detection output spectrum in a low acidic environment (0ppm to 10ppm) in example 4.

In the figure: the device comprises a laser light source 1, a frequency doubling crystal 2, a half-wave plate 3, a polaroid 4, a first total reflection mirror 5, a second total reflection mirror 6, a focusing lens 7, an aperture diaphragm 8, a plane dichroic mirror 9, a quartz cuvette 10, a coupling mirror 11, a spectrometer 12 and a double-layer series quartz cuvette 13.

Detailed Description

The following describes in detail specific embodiments of the present invention with reference to the accompanying drawings.

Example 1: fig. 1 is a light path diagram of a nile red dye laser for realizing acid detection in the present invention. This system includes a laser pump source, an optical system, and a dye laser resonator. Wherein the laser light source 1 is Nd: YAG solid laser, the light emitted by the pump source is irradiated on the energy adjusting system composed of a half-wave plate 3 and a polaroid 4 through a frequency doubling crystal 2. The first total reflection mirror 5 and the second total reflection mirror 6 are the same laser dichroic mirror, and transmit out the pump light with 1064nm, and reflect the frequency doubling light with 532nm back to be used as the direct pump light of the dye laser resonant cavity. The focusing lens 7 and the aperture stop 8 serve as a shaping system for the incident pump light. The focusing lens 7 is made of common K9 glass and has a focal length of 100 mm; the aperture diaphragm 8 has a light-passing opening of 5 mm. The dye laser resonator comprises a planar dichroic mirror 9, a quartz cuvette 10 filled with a nile red solution, and an output coupling mirror 11. The plane dichroic mirror 9 is located 10mm behind the small-hole diaphragm 8, the quartz cuvette 10 is located 15mm behind the plane dichroic mirror 9, and the distance between the quartz cuvette and the output coupling mirror 11 at the rear is 10 mm. Finally, the output laser is connected to the spectrometer 12 for analysis. The first total reflection mirror 5 and the second total reflection mirror 6 are the same laser dichroic mirror, and have high transmission (T > 99%) at 1064nm and high reflection (R > 99%) at 532nm through surface coating. The laser resonant cavity part consists of a plane dichroic mirror 9, a quartz cuvette 10 filled with a nile red solution and an output coupling mirror 11. The coated planar dichroic mirror 9 is highly transmissive at 532nm (T90%) and highly reflective at 560nm to 700nm (R90%). The quartz cuvette 10 contains a Nile red organic solution for acid detection, the used glass material is common optical quartz glass, the optical path is 5mm, and the transmissivity of the front optical surface and the rear optical surface in a visible light range exceeds 99.5%. The surface of the output coupling mirror 11 is coated, and the reflectivity is 85% in the range of 400nm to 700 nm.

As shown in figure 2, a set of output laser spectrograms in acid environments with different concentrations are obtained by placing a prepared 60 mug/mL Nile Red ethanol solution in a cuvette and simultaneously doping prepared sulfuric acid/ethanol mixed solutions with different concentrations into a Nile Red ethanol solution system. Wherein curve 1 represents the 532nm pump light and curves 2,3,4,5,6,7,8 represent the output laser spectra at doped sulfuric acid concentrations of 0ppm,10ppm,20ppm,50ppm,100ppm,200ppm and 500ppm, respectively. It can be seen that as the sulfuric acid concentration increases from 0ppm to 500ppm, the peak position of the output laser is red shifted from 652.94nm to 678.85nm, covering nearly 26 nm.

Example 2: this example differs from example 1 in that the concentration of the nile red ethanol solution was increased to 200 μ g/mL.

As shown in FIG. 3, in a 200 μ g/mL solution of Nile Red in ethanol, the output laser peak position increased from 653.82nm to 679.15nm, covering also approximately 26nm, as the sulfuric acid concentration increased from 0ppm to 100 ppm. Wherein curve 1 represents the 532nm pump light and curves 2,3,4,5,6 represent the output laser spectra at doped sulfuric acid concentrations of 0ppm,10ppm,20ppm,50ppm and 100ppm, respectively. Compared with example 1, in the detection range of example 2, under the sulfuric acid environment with 100ppm or more, the output laser peak position is almost unchanged, resulting in the reduction of the detection range, so that a 60 μ g/mL nile red ethanol solution is recommended as the base material for acidic detection.

As shown in fig. 4, the output wavelength exhibits a certain degree of instability with increasing detection time during the detection process, i.e., the wavelength shifts up to 1.5nm under the same concentration environment. FIG. 4 shows the time instability and concentration drift phenomena in different acidic environments. Wherein curves 1,2,3,4,5,6 represent the drift phenomenon of the output laser spectrum with the measurement time at sulfuric acid concentrations of 10ppm,20ppm,50ppm,100ppm,200ppm and 500ppm, respectively.

Example 3: this example differs from example 1 in that the single-layer cuvette structure was optimized as a double-layer tandem cuvette structure. As shown in fig. 5, the planar dichroic mirror 9, the double-layer tandem quartz cuvette 13, and the output coupling mirror 11 constitute a resonant cavity. In a double-layer tandem quartz cuvette 13, the front chamber was filled with 60. mu.g/mL of rhodamine 6G in ethanol and the back chamber was filled with 60. mu.g/mL of Nile Red in ethanol. As shown in FIG. 6, curve 1 shows the pump light at 532nm, curve 2 shows the laser spectrum of rhodamine 6G/ethanol solution in the double-sided cuvette structure, and curves 3,4,5,6,7,8, and 9 respectively represent the laser spectrum of Nile Red/ethanol solution outputted under sulfuric acid atmosphere at concentrations of 0ppm,10ppm,20ppm,50ppm,100ppm,200ppm, and 500 ppm. It can be seen that in 60 μ g/mL nile red ethanol solution, as the concentration of doped sulfuric acid is greatly increased from 0ppm to 500ppm, the output laser wavelength covers 636nm to 676nm, and the detection range is increased by nearly 1.5 times compared with the single cuvette structure in example 1, which is nearly a 40nm range.

As shown in FIG. 7, curve 1 shows the pump light at 532nm, curve 2 shows the laser spectrum of rhodamine 6G/ethanol solution in the double-sided cuvette structure, and curves 3,4,5,6, and 7 respectively represent the laser spectrum of the Nile Red/ethanol solution output under sulfuric acid environment with concentrations of 1ppm,2ppm,5ppm,8ppm, and 10 ppm. It can be seen that in a nile red ethanol solution of 60 μ g/mL, considering a low-concentration sulfuric acid environment, the sulfuric acid doping concentration is slowly increased from 0ppm to 10ppm, and the output laser spectrum shows a characteristic of "proportional laser", that is, as the doping sulfuric acid concentration is increased, the laser peak intensity originally around 636nm is gradually reduced, and another laser peak at 654nm begins to appear and the intensity gradually dominates. When the concentration of doped sulfuric acid was increased to 10ppm, the laser peak at 636nm almost disappeared, and the laser peak at 654nm became dominant in output. Therefore, the detection range of the sulfuric acid can be expanded by the method, and by the system, the doped sulfuric acid concentration can be detected by outputting the laser peak position and can be determined by outputting the intensity ratio of the dual-wavelength laser peak in a low-concentration sulfuric acid environment, so that the accuracy of the detection result is increased.

To sum up, the utility model discloses utilized the solvation color development characteristic of nile red, adulterated its sulphuric acid/ethanol solution with different concentrations, obtained the laser output under the different doping concentration to reach the purpose that sulphuric acid detected. Meanwhile, in order to enlarge the detection range and avoid the phenomena of time instability and wavelength drift in the experiment, a novel method of connecting two cuvettes in series is adopted, and a Nile red/ethanol solution and a rhodamine/ethanol solution are respectively placed in the front and back double cavities of the cuvettes, so that laser output in a 40nm tuning range is obtained, and the time instability of the output laser is well inhibited. The nile red dye laser for detecting the concentration of the sulfuric acid is precise and accurate, can continuously increase the detection range by changing a substrate material (such as Congo red) and a detection target (such as nitric acid and acetic acid), and has wide application prospects in the fields of biochemical detection, laser chemistry, laser spectrum technology and the like.

Claims

1. A nile red dye laser for acid detection, comprising: the dye laser resonant cavity consists of a laser pumping source, an optical system and a dye laser resonant cavity, wherein the laser source (1) is Nd: YAG solid laser, the pumping source light through frequency doubling crystal (2) to the half-wave plate (3) and the polarizing plate (4) formed energy regulation system, the first total reflection mirror (5) and the second total reflection mirror (6) are the same laser two-way mirror, 1064nm pump light transmission, 532nm frequency doubling light reflection as the dye laser resonant cavity direct pump light, the focusing lens (7) and the small hole diaphragm (8) as the incident pump light shaping system, the dye laser resonant cavity including the plane two-way mirror (9), the device comprises a quartz cuvette (10) filled with a Nile red solution and an output coupling mirror (11), wherein the plane dichroic mirror (9) is located 10mm behind the small-hole diaphragm (8), the quartz cuvette (10) is located 15mm behind the plane dichroic mirror (9) and 10mm away from the output coupling mirror (11) behind the plane dichroic mirror, and finally output laser is connected into a spectrometer (12) for analysis.

2. The nile red dye laser for acid detection of claim 1, wherein: the fluorescent/laser material used in the experiment is Nile Red with molecular formula C₂₀H₁₈N₂O₂The organic solvent is ethanol (C)₂H₅OH), the net content GC of ethanol is more than or equal to 99.5 percent.

3. The nile red dye laser for acid detection of claim 1 or 2, wherein the concentration of nile red in ethanol solvent is 60 μ g/mL.

4. The nile red dye laser for acid detection of claim 1, wherein: the laser light source (1) is Nd, YAG solid laser, and the output laser wavelength is 1064 nm; the frequency doubling crystal (2) is a potassium titanyl phosphate (KTP) crystal.

5. The nile red dye laser for acid detection of claim 1, wherein: the first total reflection mirror (5) and the second total reflection mirror (6) are the same laser dichroic mirror, and have high transmission (T > 99%) at 1064nm and high reflection (R > 99%) at 532nm through surface coating.

6. The nile red dye laser for acid detection of claim 1, wherein: the focusing lens (7) is made of common K9 glass, and the focal length is 100 mm; the light-passing opening of the aperture diaphragm (8) is 5 mm.

7. The nile red dye laser for acid detection of claim 1, wherein: the laser resonant cavity consists of a plane dichroic mirror (9), a quartz cuvette (10) filled with a Nile red solution and an output coupling mirror (11), the coated plane dichroic mirror (9) has high transmittance (T is 90%) at 532nm, high reflectance (R is 90%) at 560nm to 700nm, the quartz cuvette (10) is filled with a Nile red organic solution for acid detection, the used glass material is common optical quartz glass, the optical path is 5mm, the transmittance of front and rear optical surfaces in a visible light range exceeds 99.5%, the surface of the output coupling mirror (11) is coated, and the reflectance is 85% in a range of 400nm to 700 nm.

8. The nile red dye laser for acid detection of claim 1, wherein: the acid environment provider used in the experiment was sulfuric acid (H), a representative of non-volatile acids₂SO₄) The sulfuric acid/ethanol solution with different concentrations is mixed with the Nile red solution, and the acidity of the solution system can be continuously changed.

9. The nile red dye laser for acid detection of claim 1, wherein: in order to realize the purpose of expanding the acidity detection range, a method of connecting cuvettes in series can be adopted, and the specific implementation method is as follows: the single cuvette is replaced by a double-layer quartz cuvette connected in series, wherein the front cavity is filled with 60 mu G/mL rhodamine 6G ethanol solution, the rear cavity is filled with 60 mu G/mL nile red ethanol solution, and the aim of expanding the acidity detection range is achieved by measuring the laser spectrum of sulfuric acid/ethanol solution with different concentrations of 0ppm to 500 ppm.