Handheld LIBS (laser-induced breakdown spectroscopy) double-channel light path analyzer

Abstract

The invention discloses a handheld LIBS (laser-induced breakdown spectroscopy) double-channel light path analyzer, which belongs to the field of light path analyzers and comprises a laser, two parallel spectrometers are arranged on one side of the laser, and a test sample is arranged on one side of one spectrometer; an excitation light path is arranged between the test sample and the laser device, a first collection light path is arranged between the test sample and one spectrograph, a second collection light path is arranged between the test sample and the other spectrograph, and the excitation light path specifically comprises a first excitation light path lens arranged on the other side of the laser device and a second excitation light path lens arranged on the other side of the laser device; a second excitation light path lens is arranged on one side of the first excitation light path lens, the included angle between the first excitation light path lens and the laser is 15.05 degrees, and the included angle between the first excitation light path lens and the second excitation light path lens is 15.05 degrees. According to the invention, the signal acquisition efficiency can be improved so as to realize efficient acquisition, and chromatic aberration caused when LIBS signals are collected can be avoided.

Description

Technical Field

[0001] The invention relates to the field of optical path analyzers, in particular to a handheld LIBS dual-channel optical path analyzer. Background Art

[0002] LIBS (Laser-Induced Breakdown Spectroscopy) is a non-contact, non-destructive, fast and highly sensitive spectral analysis technology. Its working principle is to focus a beam of high-energy pulsed laser on the surface of the sample. When the laser irradiance exceeds the breakdown threshold of the sample, a small amount of material will be ablated and excited to produce plasma. When atoms and ions in the excited state migrate from the high energy state back to the low energy state, they will emit characteristic light radiation with a specific wavelength. This characteristic light radiation is like the "fingerprint" of the element and is unique. By analyzing the peak position, peak intensity and other information in the plasma emission spectrum with a sensitive spectrometer, the type of element in the sample and the corresponding content can be identified, thereby realizing the identification, classification, qualitative and quantitative analysis of the material.

[0003] Generally speaking, laboratory LIBS systems are too large to be used directly for outdoor field detection. Commercial handheld LIBS detection equipment on the market often only uses a simple single-lens single-channel collection optical path, which will cause chromatic aberration when collecting LIBS signals (for example, 200-800nm, the focus point of the 200nm signal is far away from the focus point of the 800nm ​​signal), and the efficiency of wide-band LIBS signal collection is low. However, LIBS equipment often has multi-element detection requirements in actual production applications, and traditional handheld LIBS equipment cannot achieve efficient collection for such requirements.

[0004] Therefore, those skilled in the art provide a handheld LIBS dual-channel optical path analyzer to solve the problems raised in the above background technology. Summary of the invention

[0005] The purpose of the present invention is to provide a handheld LIBS dual-channel optical path analyzer, which can improve the signal acquisition efficiency to achieve efficient acquisition and avoid chromatic aberration when collecting LIBS signals, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A handheld LIBS dual-channel optical path analyzer comprises a laser, one side of the laser is provided with two parallel spectrometers, one side of one of the spectrometers is provided with a test sample;

[0008] An excitation light path is provided between the test sample and the laser, a first collection light path is provided between the test sample and one of the spectrometers, and a second collection light path is provided between the test sample and another of the spectrometers.

[0009] As a further solution of the present invention: the excitation light path specifically includes: a first excitation light path lens arranged on the other side of the laser, a second excitation light path lens is arranged on one side of the first excitation light path lens, and the angle between the first excitation light path lens and the laser is 15.05°, the angle between the first excitation light path lens and the second excitation light path lens is 15.05°, and the second excitation light path lens is facing the test sample.

[0010] As a further solution of the present invention: the first excitation light path lens is coated with a 1064nm infrared reflective film.

[0011] As a further solution of the present invention: the second excitation light path lens is coated with a 1064nm infrared anti-reflection film.

[0012] As a further solution of the present invention: the first collecting light path specifically includes: a first collecting light path lens 1 and a first collecting light path lens 2 arranged between the spectrometer and the test sample, and the test sample, the first collecting light path lens 1, the first collecting light path lens 2 and a spectrometer are on the same axis.

[0013] As a further solution of the present invention: the second collecting light path specifically includes: a second collecting light path lens three arranged on one side of the other spectrometer, a second collecting light path lens two is provided on one side of the second collecting light path lens three, and a second collecting light path lens one is provided on one side of the second collecting light path lens two, the second collecting light path lens one is facing the test sample, and the angle between the second collecting light path lens one and the second collecting light path lens two is 22.5°, the angle between the second collecting light path lens two and the second collecting light path lens three is 22.5°, and the second collecting light path lens three is facing the other spectrometer.

[0014] As a further solution of the present invention: the second collecting light path lens 2 is coated with an ultraviolet-visible enhanced reflection film.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. This application adopts a LIBS dual-channel optical path for collection and analysis. Compared with the traditional single-lens single-channel collection optical path, it can improve the signal collection efficiency to achieve efficient collection and avoid chromatic aberration when collecting LIBS signals.

[0017] 2. The present application adopts a safe and efficient optical fiber communication system based on complex conjugate dual emission coding and time-domain dispersion self-focusing effect for information transmission, wherein complex conjugate dual emission coding is used to solve the polarization fading problem and simplify the receiver structure; combined with time-domain dispersion self-focusing, physical encryption and decryption are achieved to ensure the security of data transmission; and DSCM technology is used to simplify the dispersion compensation process and improve transmission performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a handheld LIBS dual-channel optical path analyzer;

[0019] Figure 2 A side view of a handheld LIBS dual-channel optical path analyzer;

[0020] Figure 3 A schematic diagram of complex conjugate dual emission coding in a handheld LIBS dual-channel optical path analyzer;

[0021] Figure 4 Schematic diagram of safe transmission of time-domain dispersion self-focusing effect in a handheld LIBS dual-channel optical path analyzer.

[0022] In the figure: 1. Laser; 2. First excitation light path lens; 3. Second excitation light path lens; 4. Test sample; 5. First collection light path lens 1; 6. First collection light path lens 2; 7. Second collection light path lens 1; 8. Second collection light path lens 2; 9. Second collection light path lens 3; 10. Spectrometer. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] As mentioned in the background technology of this application, research has found that existing handheld LIBS detection equipment often only uses a simple single-lens single-channel collection optical path, which will cause chromatic aberration when collecting LIBS signals (for example, 200-800nm, the focus point of the 200nm signal is far away from the focus point of the 800nm ​​signal), and the efficiency of wide-band LIBS signal collection is low. However, LIBS equipment often has multi-element detection requirements in actual production applications. Traditional handheld LIBS equipment cannot achieve efficient collection for such requirements and has certain defects.

[0025] In order to solve the above-mentioned defects, the present application discloses a handheld LIBS dual-channel optical path analyzer, which can improve the signal acquisition efficiency to achieve efficient acquisition and avoid chromatic aberration when collecting LIBS signals.

[0026] The following will describe in detail how the solution of the present application solves the above technical problems in conjunction with the accompanying drawings.

[0027] See also Figure 1 In an embodiment of the present invention, a handheld LIBS dual-channel optical path analyzer includes a laser 1, two parallel spectrometers 10 are provided on one side of the laser 1, and a test sample 4 is provided on one side of one of the spectrometers 10; an excitation optical path is provided between the test sample 4 and the laser 1, and a first collection optical path is provided between the test sample 4 and one spectrometer 10, and a second collection optical path is provided between the test sample 4 and another spectrometer 10. The present application adopts a LIBS dual-channel optical path for collection and analysis, which can improve the signal collection efficiency to achieve efficient collection compared to the traditional single-lens single-channel collection optical path, and can avoid chromatic aberration when collecting LIBS signals.

[0028] In this embodiment, the excitation light path specifically includes: a first excitation light path lens 2 disposed on the other side of the laser 1, a second excitation light path lens 3 is disposed on one side of the first excitation light path lens 2, and the angle between the first excitation light path lens 2 and the laser 1 is 15.05°, the angle between the first excitation light path lens 2 and the second excitation light path lens 3 is 15.05°, and the second excitation light path lens 3 faces the test sample 4. Figure 1 As shown, the laser is emitted by the laser 1, and then focuses on the test sample 4 through the first excitation optical path lens 2 and the second excitation optical path lens 3, bombarding the surface of the test sample 4. When the laser exceeds the breakdown threshold of the test sample 4, a small amount of material will be ablated and excited to generate plasma. At the end of the laser pulse, the plasma diffuses and cools rapidly. During this period, the atoms and ions in the excited state migrate from the high energy state back to the low energy state, and radiate characteristic light radiation (LIBS signal) with a specific wavelength outward.

[0029] In this embodiment, the first excitation light path lens 2 is coated with a 1064nm infrared reflective film. Infrared reflective film is a film that has enhanced reflection in the infrared spectrum band through a special process on the surface or interface of an optical element. The infrared reflective film is usually composed of a multilayer film, or it can be a single-layer film. The film layer material is mainly metal material and dielectric material. According to the different reflection bands and functional requirements, infrared reflective films can be divided into two categories: metal reflective films and dielectric reflective films. The metal reflective film layer has a complex refractive index with a high extinction coefficient k value in the infrared wide spectrum range, thereby obtaining a high reflectivity; and the protective film layer is usually an infrared transparent dielectric film layer. The infrared reflective film can reflect the incident infrared light and reduce energy loss. In the field of architecture, it can reduce the thermal damage of infrared light to buildings and people, improve indoor comfort, and reduce the energy consumption of air conditioning and heating. In the automotive field, it can improve the efficiency of lighting lamps, reduce the speed of light decay, and extend the service life.

[0030] In this embodiment, the second excitation light path lens 3 is coated with a 1064nm infrared anti-reflection film. Infrared anti-reflection film, also known as "infrared anti-reflection film", is a thin film made by special coating technology, which is mainly used to adjust the transmittance and reflectivity of light to reduce solar radiation and increase light transmittance. The working principle of the infrared anti-reflection film is to use the interference phenomenon of light to reduce reflected light and enhance transmitted light. Specifically, the anti-reflection film is composed of multiple layers of transparent medium films alternately superimposed. When light is incident on the surface of the anti-reflection film, due to the different refractive indices of different medium layers, the light will be reflected and refracted when it propagates in each layer of the medium. When these reflected waves and refracted waves pass through multiple layers of medium, due to the different thickness and refractive index of each layer of the medium, different phase differences will be generated, thereby generating interference. By precisely controlling the thickness and refractive index of each layer of the film, the reflected light wave can produce destructive interference after multiple reflections and refractions, thereby reducing the intensity of the reflected light. At the same time, the transmitted light wave is relatively increased in intensity due to the less interference it is subjected to. Infrared anti-reflection film can significantly improve the transmittance of infrared light, allowing more infrared light to pass through the film and enter the target object or detection system. By reducing the intensity of reflected light, infrared anti-reflection film can reduce the reflection loss of light on the surface of the film and improve the utilization efficiency of light. Infrared anti-reflection film can usually maintain high transmittance and low reflectivity in a wider infrared spectrum range. Infrared anti-reflection film has good chemical stability and thermal stability, and can maintain its performance unchanged in harsh environments.

[0031] In this embodiment, the first collecting light path specifically includes: a first collecting light path lens 1 5 and a first collecting light path lens 2 6 arranged between a spectrometer 10 and a test sample 4, and the test sample 4, the first collecting light path lens 1 5, the first collecting light path lens 2 6 and a spectrometer 10 are on the same axis.

[0032] In this embodiment, the second collecting light path specifically includes: a second collecting light path lens 3 9 disposed on one side of another spectrometer 10, a second collecting light path lens 2 8 is disposed on one side of the second collecting light path lens 3 9, and a second collecting light path lens 1 7 is disposed on one side of the second collecting light path lens 2 8, the second collecting light path lens 1 7 faces the test sample 4, and the angle between the second collecting light path lens 1 7 and the second collecting light path lens 2 8 is 22.5°, the angle between the second collecting light path lens 2 8 and the second collecting light path lens 3 9 is 22.5°, and the second collecting light path lens 3 9 faces another spectrometer 10. Figure 2 As shown, the LIBS signal is collected through a dual-channel optical collection path (i.e., a first optical collection path and a second optical collection path), and the spectrometer 10 is used to analyze the peak position (qualitative), peak intensity and other information (quantitative) in the plasma emission spectrum (LIBS signal spectrum) to identify the type and corresponding content of the elements in the test sample 4, thereby achieving the purpose of material detection.

[0033] In this embodiment, the second collecting light path lens 2 8 is coated with an ultraviolet-visible enhanced reflective film. The ultraviolet-visible enhanced reflective film is a special optical film that can provide enhanced reflective performance in the ultraviolet and visible light bands. The working principle of the ultraviolet-visible enhanced reflective film is based on the interference effect of light. By coating multiple layers of thin films with different refractive indices on a substrate, when light is incident on the film layer, multiple reflections and refractions will occur between the layers of the film. By precisely controlling the thickness and refractive index of each layer of the film, light of a specific wavelength can produce constructive interference between the multiple layers of the film, thereby enhancing the intensity of the reflected light. The ultraviolet-visible enhanced reflective film can provide a reflectivity of up to 90% or more in the ultraviolet and visible light bands, and the specific value depends on the design of the film layer and the material selection. By optimizing the film layer structure and material combination, the reflective film can maintain a high reflectivity in a wider ultraviolet and visible light spectrum range. A high-quality ultraviolet-visible enhanced reflective film should have good mechanical properties and stability, and be able to withstand certain external forces and environmental changes without affecting its reflective performance.

[0034] In this embodiment, after analyzing the peak position (qualitative) and peak intensity (quantitative) in the plasma emission spectrum (LIBS signal spectrum), the spectrometer 10 of the present application adopts a safe and efficient optical fiber communication system based on complex conjugate dual emission coding and time domain dispersion self-focusing effect for transmission, specifically:

[0035] (I) Complex conjugate dual transmit coding: Complex conjugate dual transmit coding is used to solve the polarization fading problem and simplify the receiver structure.

[0036] In the transmitter:

[0037] X polarization first sends the "s1" signal, and then repeatedly sends the "s2" signal (equivalent to Figure 3 -s2* in, i.e., the conjugate of the s2 signal);

[0038] X polarization first sends "s2", and then repeats the "s1" signal in a special way (equivalent to Figure 3 s1* in , i.e. the conjugate of the s1 signal);

[0039] What is received at the receiving end is a dual-polarization mixture of these original signals and the "conjugated" signal;

[0040] The use of dual polarization and a special coding method (Alamouti) makes information transmission more reliable and efficient, and can work normally even in complex environments.

[0041] (II) Secure transmission using time-domain dispersion self-focusing effect: Combined with time-domain dispersion self-focusing, physical encryption and decryption are realized to ensure the security of data transmission, such as Figure 4 shown.

[0042] (III) Digital Subcarrier Multiplexing (DSCM): DSCM technology is used to simplify the dispersion compensation process and improve transmission performance.

[0043] Digital subcarrier multiplexing is a method of combining (multiplexing) multiple communication signals for transmission over a single optical fiber. The following are its main features and advantages:

[0044] High spectrum efficiency: The DSM system generates mutually orthogonal subcarrier channels digitally, which makes bandwidth allocation more flexible and the granularity of data rate can be adjusted according to demand.

[0045] Flexible bandwidth allocation: The number of allocated subcarriers can be selected based on traffic demand, thus achieving variable bandwidth allocation.

[0046] Strong adaptability: The DSM system can dynamically adjust the number of subcarrier channels detected without changing the system configuration.

[0047] Strong anti-interference capability: Due to the orthogonality between subcarriers, the DSM system has a high tolerance to interference such as dispersion, phase noise and fiber nonlinearity.

[0048] This technology is widely used in optical transmission networks, especially in scenarios requiring high capacity and long-distance transmission.

[0049] The working principle of the present invention is: the laser is emitted by the laser 1, and then focuses on the test sample 4 through the first excitation optical path lens 2 and the second excitation optical path lens 3, bombarding the surface of the test sample 4. When the laser exceeds the breakdown threshold of the test sample 4, a small amount of material will be ablated and excited to generate plasma. When the laser pulse ends, the plasma diffuses and cools rapidly. During this period, the atoms and ions in the excited state migrate back from the high energy state to the low energy state, and radiate outward to emit characteristic light radiation (LIBS signal) with a specific wavelength. Subsequently, the signal is collected through the dual-channel LIBS signal collection optical path (i.e., the first collection optical path and the second collection optical path), and the peak position (qualitative), peak intensity and other information (quantitative) in the plasma emission spectrum (LIBS signal spectrum) are analyzed by the spectrometer 10 to identify the type and corresponding content of the elements in the test sample 4, thereby achieving the purpose of material detection. During the process of collecting signals by the first collecting optical path, the LIBS signal passes through the first collecting optical path lens 1 5 and the first collecting optical path lens 2 6 in sequence to reach a spectrometer 10. During the process of collecting signals by the second collecting optical path, the LIBS signal passes through the second collecting optical path lens 1 7, the second collecting optical path lens 2 8, and the second collecting optical path lens 3 9 in sequence to reach another spectrometer 10.

[0050] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0051] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A handheld LIBS dual-channel optical path analyzer, characterized in that: It comprises a laser (1), one side of the laser (1) is provided with two parallel spectrometers (10), one side of one of the spectrometers (10) is provided with a test sample (4); An excitation light path is provided between the test sample (4) and the laser (1), a first collection light path is provided between the test sample (4) and one of the spectrometers (10), and a second collection light path is provided between the test sample (4) and another of the spectrometers (10).

2. A handheld LIBS dual-channel optical path analyzer according to claim 1, characterized in that: The excitation light path specifically comprises: a first excitation light path lens (2) arranged on the other side of the laser (1); a second excitation light path lens (3) is arranged on one side of the first excitation light path lens (2); the angle between the first excitation light path lens (2) and the laser (1) is 15.05°; the angle between the first excitation light path lens (2) and the second excitation light path lens (3) is 15.05°; and the second excitation light path lens (3) faces the test sample (4).

3. A handheld LIBS dual-channel optical path analyzer according to claim 2, characterized in that: The first excitation light path lens (2) is coated with a 1064nm infrared reflection film.

4. A handheld LIBS dual-channel optical path analyzer according to claim 2, characterized in that: The second excitation light path lens (3) is coated with a 1064nm infrared anti-reflection film.

5. A handheld LIBS dual-channel optical path analyzer according to claim 1, characterized in that: The first collecting light path specifically comprises: a first collecting light path lens 1 (5) and a first collecting light path lens 2 (6) arranged between a spectrometer (10) and a test sample (4); the test sample (4), the first collecting light path lens 1 (5), the first collecting light path lens 2 (6) and a spectrometer (10) are on the same axis.

6. A handheld LIBS dual-channel optical path analyzer according to claim 1, characterized in that: The second collecting light path specifically comprises: a second collecting light path lens three (9) arranged on one side of the other spectrometer (10); a second collecting light path lens two (8) is arranged on one side of the second collecting light path lens three (9); and a second collecting light path lens one (7) is arranged on one side of the second collecting light path lens two (8); the second collecting light path lens one (7) faces the test sample (4); and the angle between the second collecting light path lens one (7) and the second collecting light path lens two (8) is 22.5°; the angle between the second collecting light path lens two (8) and the second collecting light path lens three (9) is 22.5°; and the second collecting light path lens three (9) faces the other spectrometer (10).

7. A handheld LIBS dual-channel optical path analyzer according to claim 6, characterized in that: The second collecting light path lens 2 (8) is coated with an ultraviolet-visible enhanced reflection film.

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