A laser-induced breakdown plasma spectral signal acquisition device, method, and laser probe experimental setup based on Bessel beams.

Abstract

This invention relates to a laser-induced breakdown plasma spectral signal acquisition device, method, and laser probe experimental apparatus based on a Bessel beam. The spectral signal acquisition device includes multiple acquisition heads, which are circumferentially spaced along a reference axis perpendicular to a reference plane. The axes of the acquisition heads are coplanar with the reference axis, and each acquisition head can move axially relative to the reference plane along the reference axis. During detection, this application only requires changing the sample's position on a plane parallel to the reference plane to switch the sample detection point. The plasma center corresponding to any detection point on the sample surface falls within the acquisition area, ensuring that at least one acquisition head can acquire effective spectral information. This reduces fluctuations in spectral signal collection efficiency, improves the accuracy and long-term stability of the detection results, and significantly increases detection efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of spectrometers, specifically to a laser-induced breakdown plasma spectral signal acquisition device, method, and laser probe experimental apparatus based on a Bessel beam. Background Technology

[0002] Laser-induced breakdown spectroscopy (LIBS), as a rapidly developing atomic spectroscopy analysis technique in recent years, has significant advantages such as no need for complex sample pretreatment, fast detection speed, simultaneous analysis of multiple elements, and applicability to extreme environments. It has been widely used in geological exploration, environmental pollution detection, and non-destructive identification of cultural relics, and has become one of the core technical means for elemental analysis of complex matrix samples.

[0003] Traditional Gaussian beam LIBS systems are limited by the diffraction characteristics of the beam. The energy density of the laser focused spot is highly sensitive to the relative distance between the sample surface and the focusing lens. When the sample surface has undulations or insufficient flatness, defocusing is prone to occur after switching detection points, leading to insufficient laser breakdown threshold or unstable plasma morphology, directly affecting the reliability of the detection results. To address this pain point, the non-diffraction and self-restoring characteristics of Bessel beams provide a new solution for improving the performance of LIBS technology: after coupling Bessel beams with LIBS technology, the laser can maintain relatively stable energy density over a long depth of focus. Even if there is a certain degree of height difference on the sample surface, it can still effectively break down the sample and generate stable plasma after switching detection points. This significantly reduces defocusing interference caused by sample unevenness from the excitation end, improving the applicability of detecting complex surface samples.

[0004] While Bessel beams solve the stability problem of laser excitation, changes in sample surface height can still cause the spatial emission position of the plasma to shift synchronously after switching detection points. This requires synchronous adjustment of the spatial position of the spectral acquisition head, resulting in low detection efficiency. Furthermore, the accumulation of errors from multiple adjustments can lead to deviations and insufficient accuracy in the final elemental quantitative analysis results. Summary of the Invention

[0005] Based on the above description, the present invention provides a laser-induced breakdown plasma spectral signal acquisition device based on Bessel beams to solve the problem that changes in sample surface height can also cause synchronous shifts in the spatial emission position of plasma after switching detection points, requiring synchronous adjustment of the spatial position of the spectral acquisition head, resulting in low detection efficiency, and the accumulation of errors from multiple adjustments can lead to deviations and insufficient accuracy in the final elemental quantitative analysis results.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, this application provides a laser-induced breakdown plasma spectral signal acquisition device based on a Bessel beam, comprising multiple acquisition heads, which are circumferentially spaced along a reference axis perpendicular to a reference plane. The axes of the acquisition heads are coplanar with the reference axis, and the acquisition heads can move axially relative to the reference plane along the reference axis.

[0007] Preferably, the acquisition head can move radially relative to the reference plane along the reference axis, and the acquisition head can rotate relative to the reference plane about a rotation axis that is perpendicular to both its own axis and the reference axis.

[0008] Preferably, the acquisition head has at least three.

[0009] Secondly, this application provides a method for acquiring laser-induced breakdown plasma spectral signals, employing the laser-induced breakdown plasma spectral signal acquisition device based on a Bessel beam as described above, comprising: The focal points of the multiple acquisition heads are sequentially distributed along the axial direction of the reference axis, and the focal points of the multiple acquisition heads form an acquisition area; Based on the height of the sample surface relative to the reference plane and the height difference of the sample surface, the positions of the multiple acquisition heads relative to the reference plane are adjusted so that the spatial range in which the plasma center generated by the sample surface may appear completely falls within the acquisition area.

[0010] Thirdly, this application provides a laser probe experimental device based on a Bessel beam, comprising: The laser generating unit is used to generate a Bessel beam whose axis coincides with the reference axis; The laser-induced breakdown plasma spectral signal acquisition device based on Bessel beams as described above is mounted on a base, and the base is also provided with a sample stage, with a reference plane set on the sample stage. The spectral analysis and processing unit is used to receive, analyze, and process the spectral signals acquired by the multiple acquisition heads.

[0011] Preferably, the laser generating unit includes a laser, a beam expander, a reflector, a conical lens, and a focusing lens group arranged in sequence. The laser output from the laser is reflected by the reflector to the conical lens after passing through the beam expander. The beam is converted into a Bessel beam after passing through the conical lens. The Bessel beam is then directed toward the sample stage after passing through the focusing lens group.

[0012] Preferably, the conical lens and the focusing lens group can move synchronously relative to the reference plane along the reference axis.

[0013] Preferably, among the multiple sets of spectral patterns acquired by the multiple acquisition heads, the spectral signal with the highest intensity is selected as the effective spectral signal for analysis.

[0014] Compared with the prior art, the technical solution of this application has at least the following beneficial technical effects: 1. The spectral signal acquisition device of this application comprises multiple acquisition heads circumferentially spaced along a reference axis. During actual detection, the focal points of the multiple acquisition heads are sequentially distributed along the axial direction of the reference axis, forming an acquisition area. The spectral signal of the plasma centered within this acquisition area can be effectively acquired. Before formal detection, the sample is fixed on the sample stage, and the height of the sample surface relative to the reference plane and the height difference of the sample surface are measured. Based on the positional relationship between the plasma center and the corresponding detection point surface, the possible spatial range of the plasma center corresponding to each detection point can be determined. Then, the multiple acquisition heads are moved axially along the reference axis, adjusting the position of the acquisition area formed by the focal points of the multiple acquisition heads, so that the possible spatial range of the plasma center excited on the sample surface falls completely within the acquisition area. Thus, during detection, there is no need to adjust the position of the acquisition heads; only the position of the sample on a plane parallel to the reference plane needs to be changed to switch the sample detection point. The plasma center corresponding to any detection point on the sample surface falls within the acquisition area, ensuring that at least one acquisition head can acquire effective spectral information, thereby reducing fluctuations in spectral signal collection efficiency and significantly improving the accuracy and long-term stability of the detection results. By combining the stable excitation region formed by the Bessel beam, the detection point can be switched simply by changing the position of the sample on a plane parallel to the reference plane, which can significantly improve the detection efficiency.

[0015] 2. The spectral signal acquisition method of this application does not require adjustment of the acquisition head position during detection. It only needs to change the position of the sample on a plane parallel to the reference plane to switch the sample detection point. The plasma center corresponding to any detection point on the sample surface falls within the acquisition area, ensuring that at least one acquisition head can acquire effective spectral information, thereby reducing the fluctuation of spectral signal collection efficiency and significantly improving the accuracy and long-term stability of the detection results.

[0016] 3. The laser probe experimental device based on Bessel beam of this application uses Bessel beam to excite plasma on the sample surface and uses the plasma spectral signal acquisition device of this application to acquire plasma spectral signals. During detection, it is only necessary to change the position of the sample on a plane parallel to the reference plane to switch the detection point. For samples with height differences on the surface, switching the detection point will not affect the effectiveness of spectral signal acquisition, improve the accuracy and long-term stability of the detection results, and significantly improve the detection efficiency. There is no need to perform surface polishing, cutting and other pretreatment on the sample, which expands the application boundary of LIBS technology in the detection of irregular samples. Attached Figure Description

[0017] Figure 1 A schematic diagram of the structure of a laser probe experimental device based on a Bessel beam provided in an embodiment of the present invention; Figure 2 A schematic diagram of the installation of the conical lens and focusing lens group in the laser probe experimental device based on Bessel beam provided in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of the laser probe experimental device based on Bessel beam provided in an embodiment of the present invention from another perspective; Figure 4 A schematic diagram of the acquisition head and its focal point in the laser probe experimental device based on Bessel beam provided in an embodiment of the present invention; Figure 5 This is a schematic diagram showing the positional relationship between the focal distribution of multiple acquisition heads and the possible spatial range of the plasma center in the laser-induced breakdown plasma spectral signal acquisition method in this embodiment of the invention.

[0018] Explanation of reference numerals in the attached figures: 1. Laser generating unit; 11. Laser; 12. Beam expander; 13. Mirror; 14. Conical lens; 15. Convex lens; 2. Acquisition head; 3. Base; 4. Sample stage; a. Focal point; b. Acquisition area; c. Plasma center. Detailed Implementation

[0019] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0020] Unless otherwise defined, 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 terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0021] It is understood that spatial relation terms such as "below," "under," "below," "below," "above," "above," etc., can be used here to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as "below" or "below" of the other element or feature will be oriented "above" the other element or feature. Therefore, the exemplary terms "below" and "below" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0022] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0023] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0024] Reference Figure 1 As shown, this application provides a laser probe experimental device based on a Bessel beam. The device includes a laser generation unit 1, a laser-induced breakdown plasma spectral signal acquisition device based on a Bessel beam, and a spectral analysis and processing unit.

[0025] The laser generating unit 1 is used to generate a Bessel beam, the spectral signal acquisition device is used to acquire the spectral signal of the plasma generator, and the spectral analysis and processing unit is used to receive, analyze and process the spectral signal acquired by the spectral signal acquisition device.

[0026] Reference Figure 1As shown, specifically, the laser generation unit 1 includes a laser 11, a beam expander 12, a reflector 13, a conical lens 14, and a focusing lens group arranged sequentially. The laser 11 outputs nanosecond-level pulsed laser light as the excitation source for the LIBS system, providing stable energy input for sample breakdown. The beam expander 12 expands and collimates the laser output from the laser 11, compressing the beam divergence angle. After passing through the beam expander 12, the laser output from the laser 11 is directed towards the reflector 13. The reflector 13 adjusts the beam transmission direction, reflecting the beam towards the conical lens 14. The conical lens 14 is the core element for generating the Bessel beam, converting the incident Gaussian beam into a diffraction-free Bessel beam. After passing through the conical lens 14, the beam is converted into a Bessel beam. The focusing convex lens group 15 converges the Bessel beam to form a stable depth of focus region with an axial length within a set range. After passing through the focusing lens group, the Bessel beam is directed towards the sample stage 4.

[0027] In this embodiment, the laser output from laser 11 is transmitted horizontally and, after being reflected by mirror 13, is transmitted vertically downwards. Correspondingly, the conical lens 14 and the focusing lens group are distributed vertically. The focusing lens group consists of two convex lenses 15 distributed vertically with different focal lengths to form a stable depth-of-focus region at the bottom. The specific parameters of the conical lens 14 and the convex lens 15 can be designed according to actual needs. For example, the base angle of the conical lens 14 can be 2.2°, and the focusing lens group can consist of a convex lens 15 with a focal length of 100mm at the top and a convex lens 15 with a focal length of 35mm at the bottom.

[0028] Reference Figure 1 As shown, in this embodiment, a base 3 is provided below the focusing lens group, and a sample stage 4 is provided on the base 3. The sample stage 4 is used to support the sample, and the stable depth of focus area formed by the laser generating unit 1 is located above the sample stage 4.

[0029] In practical design, the sample stage 4 can be designed to move in three dimensions in space to adjust the position of the sample stage 4 and thus adjust the detection point. The specific movement method can be achieved through a precision three-dimensional translation stage, which is a conventional technical means.

[0030] Reference Figure 2 As shown, in this embodiment, the conical lens 14 and the focusing lens group are designed to move synchronously in the vertical direction to adjust the height of the stable depth-of-focus area relative to the sample stage 4, meeting the needs of sample detection at different heights. Specifically, the conical lens 14 and two convex lenses 15 can be mounted on a frame, and the frame can be mounted on a translation stage with a vertical translation direction to achieve synchronous vertical movement adjustment of the conical lens 14 and the focusing lens group.

[0031] Reference Figure 1 and Figure 3As shown, the spectral signal acquisition device is further mounted on the base 3. The spectral signal acquisition device is arranged with the axis of the vertical propagation section of the Bessel beam as the reference axis and the horizontal top surface of the sample stage 4 as the reference plane.

[0032] Reference Figure 3 and Figure 4 As shown, the spectral signal acquisition device includes multiple acquisition heads 2, which are circumferentially spaced along a reference axis perpendicular to the reference plane. The axes of the acquisition heads 2 are coplanar with the reference axis, and the acquisition heads 2 can move axially relative to the reference plane along the reference axis.

[0033] Reference Figure 5 As shown, the specific method for acquiring spectral signals using this spectral signal acquisition device is as follows: The focal points a of multiple acquisition heads 2 are distributed sequentially along the axial direction of the reference axis, and the focal points a of multiple acquisition heads 2 form the acquisition area b.

[0034] Based on the height of the sample surface relative to the reference plane and the height difference of the sample surface, the positions of multiple acquisition heads 2 relative to the reference plane are adjusted so that the possible spatial range of the plasma center c generated by the sample surface is completely within the acquisition area b.

[0035] With the above settings, during actual testing, the focal points a of multiple acquisition heads 2 are sequentially distributed along the reference axis, and the focal points a of multiple acquisition heads 2 form an acquisition area b. The spectral signal of the plasma centered in this acquisition area b can be effectively acquired.

[0036] Before formal testing, the sample is fixed on the sample stage 4. The height of the sample surface relative to the reference plane and the height difference of the sample surface are measured. Based on the positional relationship between the plasma center c and the corresponding detection point surface, the possible spatial range of the plasma center c corresponding to all detection points can be determined. Then, multiple acquisition heads 2 are moved axially along the reference axis, and the position of the acquisition area b formed by the focal points a of the multiple acquisition heads 2 is adjusted so that the possible spatial range of the plasma center c excited on the sample surface falls completely within the acquisition area b. Thus, during testing, there is no need to adjust the position of the acquisition heads 2; only the position of the sample on the plane parallel to the reference plane needs to be changed to switch the sample detection point. The plasma center c corresponding to any detection point on the sample surface falls within the acquisition area b, ensuring that at least one acquisition head 2 can acquire effective spectral information, thereby reducing fluctuations in spectral signal collection efficiency and significantly improving the accuracy and long-term stability of the detection results.

[0037] By combining the stable depth of focus region formed by the Bessel beam, the detection point can be switched simply by changing the position of the sample on a plane parallel to the reference plane, which can significantly improve detection efficiency.

[0038] Furthermore, multiple acquisition heads 2 acquire plasma spectral signals from different angles, solving the problem of weak single-angle signals caused by the elongation of the plasma axial distribution under the Bessel optical path, and improving the signal-to-noise ratio of characteristic spectral lines of low-concentration elements.

[0039] Among the multiple sets of spectral data collected by multiple acquisition heads 2, the spectral signal with the highest intensity can be selected as the effective spectral signal for analysis, thereby ensuring the accuracy of the analysis results.

[0040] In this embodiment, the reference axis is vertical, therefore, the acquisition head 2 can move vertically relative to the base 3.

[0041] Furthermore, in this embodiment, the acquisition head 2 is designed to move radially relative to the reference plane along the reference axis, and the acquisition head 2 can rotate relative to the reference plane about a rotation axis that is perpendicular to both its own axis and the reference axis.

[0042] Correspondingly, the acquisition head 2 can also move horizontally closer to or away from the reference axis, and can rotate around a horizontal rotation axis. The specific vertical and horizontal movement and rotation of the acquisition head 2 can be achieved by combining a translation stage and a rotation platform with translation and lifting functions. The specific translation stage and rotation platform are conventional technical means and will not be described in detail here.

[0043] The horizontal movement and rotation of the acquisition head 2 can simultaneously adjust the angle of the acquisition head 2 axis relative to the reference plane and the horizontal distance of the acquisition head 2 relative to the reference axis, so as to avoid the sample obstructing the acquisition field of view of the acquisition head 2 and maintain the focal position of the acquisition head unchanged, ensuring that the acquisition head 2 is in the best acquisition state to acquire spectral signals.

[0044] The spectral analysis and processing unit can use a multi-channel spectrometer (not shown in the figure). The spectral signals collected by multiple acquisition heads 2 are input into the spectrometer. After the data analysis module of the spectrometer preprocesses the multiple sets of spectral signals, the peak comparison method is used to select the spectrum with the highest intensity. Finally, the characteristic spectral line intensity of each element is obtained. Combined with the pre-established calibration curve, the content of each element in the sample is calculated.

[0045] In this embodiment, three acquisition heads 2 are used as an illustration. The height adjustment range, horizontal adjustment range, angle adjustment range, and adjustment accuracy of the acquisition heads 2 are designed according to the needs.

[0046] The accuracy of the device was verified using a raw iron ore sample with a naturally uneven surface. The maximum height difference on the sample surface was 7.2 mm. Quantitative analysis of the content of elements such as Fe, Si, Al, and Mn within the sample was required. The specific detection process included the following stages: 1. Device pre-calibration stage First, laser 11 (wavelength 1064nm, pulse energy 100mJ, pulse width 10ns) is turned on. The output Gaussian beam is expanded to a diameter of 8mm by beam expander 12. After the optical path direction is adjusted by reflector 13, it is vertically incident on conical lens 14. Conical lens 14 converts the Gaussian beam into a Bessel beam, which is then focused by focusing convex lens 15, forming a focal depth region with an axial (vertical) length of approximately 2-15mm above sample stage 4. The laser energy density fluctuation within this region is ≤8%, meeting the iron ore breakdown threshold (≥1×10⁻⁶). 9 The requirement is W / cm².

[0047] 2. Sample height measurement and adjustment of sampling head 2 The uneven iron ore sample is placed on the sample stage 4. The lowest height of the detection point on the sample surface relative to the reference plane is measured to be 3.2 mm. The three acquisition heads 2 are adjusted synchronously so that the acquisition area b formed by the focal point a of the three acquisition heads 2 covers the area 3.2 mm to 10.4 mm above the sample stage 4, so that the plasma center c generated by laser breakdown is always located within the acquisition area b.

[0048] Combining the volumetric characteristics of iron ore plasma with the spatial distribution characteristics of the characteristic spectral lines of Fe, which are the focus of this detection, the horizontal position of the acquisition head 2 and the angle of its axis relative to the reference plane are adjusted synchronously. The angle between the axis of the acquisition head 2 and the horizontal direction is set to 35°, corresponding to a distance of 25 mm between the acquisition head 2 and the reference axis, to ensure maximum optical coupling efficiency and maximize the collection efficiency of characteristic spectral lines.

[0049] 3. Spectral Acquisition and Analysis Process After parameter adjustment, pulsed laser 11 outputs a single-pulse laser, which, after being focused by the Bessel optical path, penetrates the iron ore surface to generate plasma. Three sets of acquisition heads 2 simultaneously collect the radiation signal of the plasma from different angles and transmit it via optical fiber to a three-channel spectrometer (wavelength range 180~900nm, resolution 0.05nm). The data analysis module preprocesses the three sets of spectral signals and uses the peak comparison method to select the spectrum with the highest intensity as the effective spectral signal for analysis. Finally, the characteristic spectral line intensities of each element are obtained. Combined with the pre-established calibration curve, the content of each element in the iron ore sample is calculated.

[0050] 4. Continuous detection of complex sample surfaces Repeated testing was performed on multiple (e.g., 10) detection points with height differences of 2-7 mm selected on the surface of the same iron ore. The results showed that the relative standard deviation of the Fe element content detected by this device was 3.8%, indicating a significant improvement in detection accuracy. The detection process does not require pretreatment such as cutting or polishing of the iron ore sample. The detection time for a single point is ≤2s, and the detection time for a single sample is ≤30s, fully meeting the needs of rapid on-site ore detection.

[0051] The laser probe experimental setup based on Bessel beams in this embodiment has the following advantages: Significantly improved signal collection efficiency: The three array-distributed acquisition heads 2 can collect plasma emission spectrum signals from multiple angles, significantly improving the overall signal collection efficiency. This effectively solves the problem of weak single-angle signals caused by the elongation of the plasma axial distribution under the Bessel optical path, and improves the signal-to-noise ratio of characteristic spectral lines of low-concentration elements by at least one order of magnitude.

[0052] Significantly enhanced applicability to complex surface sample detection: Combining the long focal depth of the Bessel beam with the dynamic height adjustment function of the acquisition head 2, it can adapt to the detection of non-uniform samples with height differences, eliminating the need for surface polishing, cutting, and other pretreatment of the sample, thus expanding the application boundaries of LIBS technology in irregular sample detection scenarios.

[0053] Quantitative detection accuracy is greatly optimized: By dynamically adjusting the height of the acquisition head 2, the fluctuation of the plasma signal coupling efficiency can be controlled within a low range (5%). Combined with the multi-channel spectral fusion algorithm, the problem of inaccurate content detection caused by sample height differences is effectively solved, and the accuracy and long-term stability of the detection results are significantly improved.

[0054] The device is highly versatile: the adjustment parameters of the acquisition head 2 can be flexibly configured according to the needs of different detection scenarios. It is suitable for high-precision quantitative analysis in the laboratory, as well as for complex working conditions such as online detection in industrial sites and rapid screening in the field, and has good commercial promotion value.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser-induced breakdown plasma spectral signal acquisition device based on Bessel beams, characterized in that: It includes multiple acquisition heads (2), which are circumferentially distributed along a reference axis perpendicular to the reference plane. The axis of the acquisition head (2) is coplanar with the reference axis, and the acquisition head (2) can move axially relative to the reference plane along the reference axis.

2. The laser-induced breakdown plasma spectral signal acquisition device based on Bessel beams according to claim 1, characterized in that: The acquisition head (2) can move radially relative to the reference plane along the reference axis, and the acquisition head (2) can rotate relative to the reference plane about a rotation axis that is perpendicular to both its own axis and the reference axis.

3. The laser-induced breakdown plasma spectral signal acquisition device based on Bessel beams according to claim 1, characterized in that: The acquisition head (2) has at least three.

4. A method for acquiring laser-induced breakdown plasma spectral signals, employing the laser-induced breakdown plasma spectral signal acquisition device based on a Bessel beam as described in any one of claims 1-3, characterized in that, include: The focal points (a) of the multiple acquisition heads (2) are sequentially distributed along the axial direction of the reference axis, and the focal points (a) of the multiple acquisition heads (2) form an acquisition area (b); Based on the height of the sample surface relative to the reference plane and the height difference of the sample surface, the positions of the multiple acquisition heads (2) relative to the reference plane are adjusted so that the possible spatial range of the plasma center (c) generated by the sample surface is completely within the acquisition area (b).

5. A laser probe experimental device based on a Bessel beam, characterized in that, include: A laser generating unit (1) is used to generate a Bessel beam whose axis coincides with the reference axis; The laser-induced breakdown plasma spectral signal acquisition device based on Bessel beam as described in any one of claims 1-3, wherein the device is mounted on a base (3), and the base (3) is further provided with a sample stage (4), and a reference plane is provided on the sample stage (4); The spectral analysis and processing unit is used to receive, analyze and process the spectral signals collected by the multiple acquisition heads (2).

6. The laser probe experimental apparatus based on Bessel beams according to claim 5, characterized in that: The laser generating unit (1) includes a laser (11), a beam expander (12), a reflector (13), a conical lens (14), and a focusing lens group arranged in sequence. The laser output from the laser (11) is reflected by the reflector (13) after passing through the beam expander (12) and then directed to the conical lens (14). After passing through the conical lens (14), the beam is converted into a Bessel beam. The Bessel beam is then directed to the sample stage (4) after passing through the focusing lens group.

7. The laser probe experimental apparatus based on Bessel beams according to claim 6, characterized in that: The conical lens (14) and the focusing lens group can move synchronously relative to the reference plane along the reference axis.

8. The laser probe experimental device based on Bessel beam according to claim 5: among the spectral signals collected by the multiple acquisition heads (2), the spectral signal with the highest intensity is taken as the effective spectral signal for analysis.

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