An excitation and collection device based on laser-induced breakdown spectroscopy

Abstract

The utility model relates to laser induced breakdown spectroscopy, concretely is a kind of excitation and collection device based on laser induced breakdown spectroscopy.Three-dimensional adjusting platform lets off-axis mirror can move freely in complex three-dimensional space, which makes it closely track plasma emission light with variable position due to sample difference, solves the problem that traditional fixed mirror is difficult to adapt to different sample positions.Coupled with pitch adjusting frame drives optical taper fiber to swing in vertical plane, can finely adjust the coupling position of optical taper fiber and off-axis mirror focal point, greatly improves the efficiency and accuracy of optical signal collection.Optical taper fiber is connected to spectrometer, ensuring that the collected optical signal can be efficiently analyzed.This design ensures that the detection process is not excessively disturbed by sample position changes, providing a stable and reliable data foundation for subsequent element analysis and other detection work, significantly improving the accuracy and practicality of laser induced breakdown spectroscopy detection, and widening the application range of the technology in different sample detection scenarios.

Description

Technical Field

[0001] This utility model relates to laser-induced breakdown spectroscopy, specifically an excitation and acquisition device based on laser-induced breakdown spectroscopy. Background Technology

[0002] In practical applications of laser-induced breakdown spectroscopy (LIBS), the samples being tested exhibit a great deal of diversity. In terms of shape, these samples may be regular blocks or flakes, or irregular particles or powders; in terms of size, they range from large industrial parts to microscopic biological samples or tiny particles; and in terms of placement, due to different experimental conditions and operating habits, the samples may be placed at different heights and angles.

[0003] In the LIBS (Liquid Optical Spectroscopy) process, a laser beam is focused onto the sample surface, causing the sample to generate plasma. The light signal emitted by the plasma is crucial for obtaining spectral information. However, due to differences in sample height, the location of plasma generation will vary depending on the laser excitation. For example, a thicker sample and a thinner sample will generate plasma at significantly different heights under the same laser focusing conditions; even for samples of the same thickness, differences in placement will result in inconsistent plasma generation locations.

[0004] To effectively collect the light signals emitted by these plasmas, optical elements are needed for reception and reflection. Traditional fixed off-axis parabolic mirrors exhibit significant limitations when faced with samples of varying heights and positions. The fixed position of the off-axis parabolic mirror prevents adjustment based on the sample's height and location, making it difficult to accurately align with the plasma emission light in many cases. This results in a large amount of light signal not being effectively received and reflected, thus affecting the efficiency of spectral signal acquisition and the accuracy of detection results.

[0005] Therefore, it is evident that traditional fixed off-axis parabolic mirrors need to be modified in their movement to adapt to a variety of samples. Utility Model Content

[0006] To avoid and overcome the technical problems existing in the prior art, this invention provides an excitation and acquisition device based on laser-induced breakdown spectroscopy. This invention uses a three-axis adjustable method to enable the off-axis parabolic mirror to adjust its position in real time, thereby accurately aligning it with the plasma emission light and improving the accuracy of subsequent detection.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] An excitation and acquisition device based on laser-induced breakdown spectroscopy includes a flat-top laser excitation module that emits laser light to a sample, and an emission light receiving and transmitting unit for receiving and transmitting plasma emission light to an off-axis parabolic mirror. The off-axis parabolic mirror is mounted on the movable end of a three-dimensional adjustment stage, and the three-dimensional adjustment stage moves the off-axis parabolic mirror in three-dimensional space to align with the plasma emission light. An optical cone fiber is arranged in the reflection path of the off-axis parabolic mirror, and the optical cone fiber is mounted on a pitch adjustment frame, which can drive the optical cone fiber to swing in the vertical plane to coordinate with the three-dimensional adjustment stage so that the focal point of the off-axis parabolic mirror is coupled to the input end of the optical cone fiber. A spectrometer is connected to the output end of the optical cone fiber.

[0009] As a further embodiment of this utility model: the flat-top laser excitation module includes a laser, and the laser's emission optical path is sequentially arranged with a flat-top shaper that can shape the laser beam into a flat-top beam, a beam expander group that expands the flat-top beam into a parallel beam, a reflector that reflects the parallel beam, a transflector that receives the parallel beam reflected by the reflector, and a collimator that focuses the parallel light reflected by the transflector onto the sample.

[0010] As a further improvement of this utility model, the beam expander assembly includes a concave lens and a convex lens arranged sequentially along the optical axis.

[0011] As a further embodiment of this invention: the light receiving and transmitting unit includes a collimating mirror and a reflective mirror. The plasma light emitted passes through the collimating mirror and the reflective mirror in sequence and is transmitted to the off-axis parabolic mirror surface.

[0012] As a further improvement of this invention, the off-axis angle of the off-axis parabolic lens is 30°-90°, and the focal length is 50-200mm.

[0013] As a further improvement of this invention: the core diameter of the optical cone fiber is 200-600μm, and the numerical aperture is ≥0.22.

[0014] As a further improvement of this utility model, the magnification of the beam expander group is 2-5 times.

[0015] As a further improvement of this invention, the swing range of the optical cone fiber is 10° to the left and right of the vertical line.

[0016] As a further improvement of this invention, the laser emitted by the laser has a wavelength of 1064nm and a pulse width of 5ns.

[0017] As a further improvement of this utility model, the collimating lens has a diameter of 25mm and a focal length of 100mm.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] 1. The three-dimensional adjustment stage allows the off-axis parabolic mirror to move freely in complex three-dimensional space. This enables it to closely track the plasma emission light, whose position varies due to sample differences, solving the problem of traditional fixed mirrors being unable to adapt to different sample positions. Combined with the pitch adjustment frame, which moves the optical cone fiber in the vertical plane, the coupling position between the optical cone fiber and the focal point of the off-axis parabolic mirror can be precisely adjusted, greatly improving the efficiency and accuracy of light signal collection. The optical cone fiber connects to the spectrometer, ensuring that the collected light signal can be efficiently analyzed. This design ensures that the detection process is not excessively affected by changes in sample position, providing a stable and reliable data foundation for subsequent elemental analysis and other detection work. It significantly improves the accuracy and practicality of laser-induced breakdown spectroscopy detection, broadening the application range of this technology in different sample detection scenarios.

[0020] 2. The laser-emitted light passes through a flat-top shaper, transforming a common Gaussian beam into a flat-top beam with uniform energy distribution. This makes the plasma excited by the laser on the sample surface more stable, reduces signal fluctuations caused by energy inhomogeneity, and improves the repeatability of the spectral signal. The beam expander group expands the flat-top beam into a parallel beam, increasing the laser spot area on the sample, reducing energy density, avoiding excessive local ablation of the sample, and improving the uniformity of excitation. The reflector and transmission mirror guide the beam path appropriately, and the collimating lens precisely focuses the beam onto the sample. The entire module works collaboratively to ensure the stability and efficiency of laser excitation, laying a solid foundation for subsequent accurate acquisition and analysis of plasma emission light.

[0021] 3. The beam expander assembly employs a structure where concave and convex lenses are arranged sequentially along the optical axis. The concave lens first diverges the beam, and then the convex lens collimates the diverged beam. This combination effectively increases the beam diameter, achieving the beam expansion function. Compared to simple single-lens beam expanders, it better corrects aberrations, reduces beam distortion and deformation during the expansion process, and results in a higher quality beam after expansion. Furthermore, by appropriately selecting the focal lengths of the concave and convex lenses, the beam expansion magnification can be flexibly adjusted to meet the diverse beam size requirements of different experimental and testing scenarios, improving the applicability and flexibility of the device and enhancing the overall performance of the apparatus while ensuring excitation effectiveness.

[0022] 4. The collimating mirror and transmission mirror design of the emitted light receiving and transmitting unit optimizes the collection and transmission process of plasma emitted light. The collimating mirror converts divergent plasma emitted light into parallel light, facilitating subsequent optical path transmission and processing, reducing scattering and loss of the optical signal during transmission, and improving the concentration of the optical signal. The transmission mirror cleverly transmits the collimated light to the surface of the off-axis parabolic mirror, and can also partially reflect and partially transmit the light according to actual needs, achieving reasonable allocation of the optical path and improving the utilization efficiency of the optical signal. This structural design is simple and efficient, and can stably and accurately guide the plasma emitted light to the subsequent detection stage, ensuring the stable operation of the entire acquisition device and providing strong support for accurate detection. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] In the figure: 10, flat-top laser excitation module; 11, laser; 12, flat-top shaper; 13, beam expander group; 131, concave lens; 132, convex lens; 14, reflector; 15, transmission mirror; 16, collimating lens; 20, light emission and reception path; 30, off-axis parabolic mirror; 40, three-dimensional adjustment stage; 50, optical cone fiber; 60, pitch adjustment frame; 70, sample. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Please see Figure 1 In this embodiment of the utility model, a flat-top laser excitation module 10 and a plasma emission light acquisition module are included, and the plasma emission light acquisition module and the flat-top laser excitation module 10 share a reflective mirror 15 and a collimating mirror 16.

[0027] Flat-top laser excitation module 10:

[0028] Laser 11: wavelength 1064nm, pulse width 5ns, outputs a Gaussian beam which is converted into a flat-top beam by a flat-top shaper 12. The beam expander group 13 expands the beam by 2-5 times to adjust the spot size, and finally the collimating lens 16 with a focal length of 100mm focuses it onto the surface of sample 70.

[0029] Flat-top beam shaper 12: Converts the Gaussian beam output from laser 11 into a flat-top beam. It can be a refractive or diffractive beam shaping element, such as a flat-top beam shaping mirror.

[0030] Beam expander group 13: includes concave lens 131 and convex lens 132 arranged in sequence along the optical axis to expand the flat-top beam by a magnification of 2-5 times, so as to reduce the energy density and increase the spot size.

[0031] Collimating lens 16: with a diameter of 25mm and a focal length of 100mm, it collimates the plasma emitted light into a parallel beam.

[0032] Plasma emission light acquisition module:

[0033] Off-axis parabolic mirror 30: off-axis angle is 90°, focal length is 25mm, and its position is adjusted by three-dimensional adjustment stage 40 so that the reflected light is precisely pointed to the input end of optical cone fiber 50.

[0034] Three-dimensional adjustment stage 40: It adopts a commonly used three-dimensional platform and can move along the corresponding axes in the three-dimensional space formed by the X-axis, Y-axis and Z-axis to adjust the position of the off-axis parabolic mirror 30.

[0035] Optical cone fiber 50: The core diameter is 400μm. The angle can be finely adjusted by the pitch adjustment bracket 60 to ensure that the coupling efficiency of the whole optical path is >90%.

[0036] Pitch adjustment frame 60: It adopts a commonly used angle-controllable swing structure, which can drive the optical cone fiber 50 to swing in the vertical plane, with a swing range of 10° to the left and right of the vertical line.

[0037] In practical use:

[0038] Assembly and debugging of the flat-top laser excitation module 10: Select a laser 11 with a wavelength of 1064nm and a pulse width of 5ns. Install the flat-top shaper 12 and beam expander group 13 with a beam expansion factor of 3x. Select appropriate focal lengths for the concave lens 131 and convex lens 132. Install the reflector 14, transmission mirror 15, and collimator 16 sequentially in the emission path of the laser 11, ensuring that the optical axes of all optical components are aligned. During installation, carefully adjust the position and angle of each component to ensure that the laser beam propagates along the designed path. Debugging ensures that the flat-top beam shaping effect is good and that the expanded beam meets the expected requirements.

[0039] Installation and Adjustment of the Plasma Emission Light Acquisition Module: The collimating lens 16 and the transmission mirror 15 are installed at appropriate positions in the plasma generation area to ensure that the plasma emission light can smoothly pass through the collimating lens 16 and the transmission mirror 15 to reach the off-axis parabolic mirror 30. The off-axis parabolic mirror 30 is mounted on the moving end of the three-dimensional adjustment stage 40, and the optical cone fiber 50 is mounted on the pitch adjustment frame 60. The output end of the optical cone fiber 50 is connected to the spectrometer. Before detecting the sample 70, the initial positions of the three-dimensional adjustment stage 40 and the pitch adjustment frame 60 are pre-adjusted according to the approximate height and position of the sample 70. After the laser excites the sample 70 to generate plasma, the position of the off-axis parabolic mirror 30 is finely adjusted using the three-dimensional adjustment stage 40 to align it with the plasma emission light. Simultaneously, the angle of the optical cone fiber 50 is adjusted using the pitch adjustment frame 60 to achieve precise coupling between the focal point of the off-axis parabolic mirror 30 and the input end of the optical cone fiber 50, ensuring a total optical path coupling efficiency greater than 90%.

[0040] Detection Process: The laser 11 is activated to excite the sample 70. The emitted plasma light passes through the emission light receiving and transmitting unit, the off-axis parabolic mirror 30, and the optical cone fiber 50 before entering the spectrometer for analysis. The spectrometer converts the optical signal into an electrical signal, and the data is processed and analyzed by the corresponding software to finally obtain the elemental composition and content information of the sample 70. During the detection process, the laser energy and optical path parameters can be adjusted according to the actual situation, such as the properties of the sample 70 and the detection requirements, to obtain the best detection results.

[0041] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An excitation and acquisition device based on laser-induced breakdown spectroscopy, characterized in that, It includes a flat-top laser excitation module (10) that emits laser light to a sample (70), and an emission light receiving and transmitting unit for receiving and transmitting plasma emission light to an off-axis parabolic mirror; the off-axis parabolic mirror is mounted on the moving end of a three-dimensional adjustment stage (40), and the three-dimensional adjustment stage (40) drives the off-axis parabolic mirror to move in three-dimensional space to align with the plasma emission light; An optical cone fiber (50) is arranged on the reflection path of the off-axis parabolic mirror, and the optical cone fiber (50) is mounted on the pitch adjustment frame (60). The pitch adjustment frame (60) can drive the optical cone fiber (50) to swing in the vertical plane so as to cooperate with the three-dimensional adjustment stage (40) to couple the focal point of the off-axis parabolic mirror with the input end of the optical cone fiber (50). The output end of the optical cone fiber (50) is connected to a spectrometer.

2. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 1, characterized in that, The flat-top laser excitation module (10) includes a laser (11). The laser (11) has a flat-top shaper (12) that can shape the laser beam into a flat-top beam, a beam expander (13) that expands the flat-top beam into a parallel beam, a reflector (14) that reflects the parallel beam, a transflector (15) that receives the parallel beam reflected by the reflector (14), and a collimator (16) that focuses the parallel light reflected by the transflector (15) onto the sample (70).

3. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 2, characterized in that, The beam expander assembly (13) includes a concave lens (131) and a convex lens (132) arranged sequentially along the optical axis.

4. An excitation and acquisition device based on laser-induced breakdown spectroscopy according to any one of claims 1-3, characterized in that, The light receiving and transmitting unit includes a collimating mirror (16) and a reflective mirror (15). The plasma light is transmitted through the collimating mirror (16) and the reflective mirror (15) in sequence and then onto the off-axis parabolic mirror surface.

5. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 4, characterized in that, The off-axis angle of the off-axis parabolic lens (30) is 30°-90°, and the focal length is 50-200mm.

6. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 5, characterized in that, The core diameter of the optical cone fiber (50) is 200-600μm and the numerical aperture is ≥0.

22.

7. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 6, characterized in that, The magnification of the beam expander group (13) is 2-5 times.

8. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 7, characterized in that, The swing range of the optical cone fiber (50) is 10° to the left and right of the vertical line.

9. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 8, characterized in that, The laser emitted by the laser (11) has a wavelength of 1064 nm and a pulse width of 5 ns.

10. The excitation and acquisition device based on laser-induced breakdown spectrum according to claim 9, characterized in that, The collimating lens (16) has a diameter of 25 mm and a focal length of 100 mm.

Images