Laser ablation sampling system and method with ultrafast imaging function

Abstract

The present application relates to the technical field of laser ablation, and particularly relates to a laser ablation sample feeding system and method with ultrafast imaging function, the system comprising an ablation cell, a laser pulse string emission unit and a micro-light imaging unit, the ablation cell is used for accommodating a sample, the laser pulse string emission unit emits a laser beam, the laser beam is focused to the surface of the sample to ablate the sample, the micro-light imaging unit is placed at a preset position of the ablation cell, used for recording the evolution image of the ablation plume in the ablation process of the sample, and outputting image data, the monitoring capability of the system on the evolution of aerosol can be improved through the micro-light imaging unit, the generation and evolution law of the aerosol can be mastered in real time, so as to facilitate the optimization of ablation parameters and environmental parameters, thereby improving the accuracy and stability of element analysis, the problems such as lack of sample ablation monitoring means, poor analysis stability and precision in the prior art can be solved, and a new solution is provided for efficient and accurate solid sample analysis technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser ablation technology, and in particular to a laser ablation sample introduction system and method with ultrafast imaging function. BACKGROUND

[0002] As an important tool for solid sample analysis, femtosecond laser ablation sample introduction system is widely used in rock and mineral analysis in earth science research, biological tissue detection in biomedical field, new material composition exploration in material science, and many other fields. In many application scenarios, precise control and real-time monitoring of the ablation process can significantly improve the efficiency and quality of analysis, such as in trace element detection, complex sample analysis, etc.

[0003] Traditional femtosecond laser ablation sample introduction systems and related analysis techniques mainly rely on ordinary imaging devices for auxiliary monitoring. These devices have obvious limitations in time resolution and spatial resolution, making it difficult to meet the demand for precise and real-time monitoring of aerosol generated by ablation.

[0004] The structure design and monitoring method of the traditional system have problems such as aerosol monitoring lag, inability to capture the ablation transient process in real time, and disconnection between ablation dynamics imaging and optical / mass spectrometry analysis data, which makes it difficult to ensure the stability and reliability of the sample analysis process. Often, due to the inability to timely grasp the dynamic changes of aerosol, the effects of element fractionation inhibition and matrix effect reduction are not good, which further affects the accuracy of the sample analysis results. SUMMARY

[0005] The present application aims to at least solve one of the problems in the prior art or related art.

[0006] To this end, the first aspect of the present application provides a laser ablation sample introduction system with ultrafast imaging function.

[0007] The second aspect of the present application provides a laser ablation sample introduction method with ultrafast imaging function.

[0008] Therefore, according to the first aspect of the embodiments of the present application, a laser ablation sample introduction system with ultrafast imaging function is provided, which comprises:

[0009] An ablation cell for containing a sample;

[0010] A laser pulse train emission unit for emitting a laser beam for focusing on the surface of the sample to ablate the sample and generate aerosol particles;

[0011] A micro-light imaging unit is arranged at a preset position of the ablation cell, and is configured to record evolution images of ablation plumes generated by the sample during the ablation process and output corresponding image data.

[0012] In an embodiment, the micro-light imaging unit comprises:

[0013] A first micro-light imaging camera is arranged in a direction perpendicular to the sample ablation surface, and is configured to coaxially image;

[0014] A half-mirror is arranged in a light path between the first micro-light imaging camera and the ablation cell.

[0015] A first illumination unit emits a first illumination light beam, which is reflected by the half-mirror and coaxially focused on the sample surface with the laser beam. Light reflected by the sample surface is transmitted by the half-mirror and enters the first micro-light imaging camera.

[0016] A first magnifying lens is arranged at a lens of the first micro-light imaging camera, and is configured to magnify an object image.

[0017] In an embodiment, the laser ablation sample introduction system further comprises:

[0018] A lens barrel is arranged in a light path between the first micro-light imaging camera and the ablation cell, and the half-mirror is arranged in the lens barrel.

[0019] An objective lens is arranged at one end of the lens barrel close to the ablation cell.

[0020] In an embodiment, the laser ablation sample introduction system further comprises a focusing positioning unit, which comprises:

[0021] A focusing module is configured to focus on the sample surface and output focus position information.

[0022] A first dichroic mirror is arranged in a light path of the focusing light reflected by the sample surface, and is configured to reflect the focusing light of the sample surface to the focusing module.

[0023] A moving platform is configured to drive the ablation cell and the sample to move according to the focus position information, so that the sample surface is located on a focal plane of the laser beam.

[0024] In an embodiment, the laser ablation sample introduction system further comprises:

[0025] a control unit, which is signal connected with the focusing module and the moving platform, and signal connected with the weak light imaging unit and the laser pulse train emitting unit;

[0026] the control unit is configured to receive the focal position information, generate a first control signal based on the focal position information, and send the first control signal to the moving platform; and receive the image data, generate a second control signal based on the image data, and send the second control signal to the laser pulse train emitting unit;

[0027] the moving platform drives the ablation cell and the sample to move to realize automatic focusing according to the first control signal, and the laser pulse train emitting unit adjusts the emission parameters of the laser beam according to the second control signal.

[0028] In an available embodiment, the laser pulse train emitting unit comprises:

[0029] a laser for emitting the laser beam, a beam spot diameter controller for adjusting the diameter of the laser beam, and a shutter for controlling the number and timing of the laser pulse train irradiated onto the sample, which are arranged in sequence along the optical path.

[0030] In an available embodiment, the laser pulse train emitting unit further comprises:

[0031] a second dichroic mirror, which is arranged obliquely, and used for reflecting the laser beam to the sample surface, and the focusing light and the first illumination light beam can be transmitted forward and backward from the second dichroic mirror.

[0032] In an available embodiment, the weak light imaging unit comprises:

[0033] a second weak light imaging camera, which is arranged in a direction parallel to the sample ablation surface, and used for side imaging.

[0034] a second illumination unit, which is arranged on the side of the ablation cell away from the second weak light imaging camera, and the second illumination light beam emitted by the second illumination unit enters the second weak light imaging camera after penetrating the first end surface of the ablation cell, the ablation plume of the sample surface, and the second end surface of the ablation cell, and the second illumination unit comprises a pulse modulation module, which is configured to output the second illumination light beam as pulse illumination light.

[0035] A collimator is arranged at a light exit of the second illumination unit, and is configured to collimate the pulsed illumination light into parallel light beams.

[0036] In an embodiment, the laser ablation sample introduction system further comprises a visible light imaging unit arranged in a direction perpendicular to the sample ablation surface, and configured to record an image of the sample ablation surface.

[0037] According to a second aspect of the embodiments of the present application, a laser ablation sample introduction method with ultrafast imaging function is provided, which is applied to the laser ablation sample introduction system with ultrafast imaging function as described in any of the above technical solutions. The sample introduction method comprises:

[0038] firing a laser beam with preset parameters, and focusing the laser beam on a sample surface for ablation;

[0039] recording an evolution image of an ablation plume during the sample ablation process;

[0040] generating a second control signal for optimizing the ablation effect according to the evolution image;

[0041] adjusting the firing parameters of the laser beam according to the second control signal.

[0042] Compared with the prior art, the present application has at least the following beneficial effects:

[0043] The laser ablation sample introduction system with ultrafast imaging function provided by the embodiments of the present application comprises an ablation cell, a laser pulse train firing unit and a micro-light imaging unit. The ablation cell is used to accommodate a sample. The laser pulse train firing unit fires a laser beam, which is focused on the sample surface to ablate the sample. The micro-light imaging unit is arranged at a preset position of the ablation cell. The micro-light imaging unit is used to collect an evolution image of an ablation plume during the sample ablation process and output image data. The micro-light imaging unit can improve the monitoring capability of the system for aerosols, such as real-time mastering of the generation and evolution rules of aerosols and optimization of ablation parameters, so as to improve the accuracy and stability of analysis, and can realize efficient cooperation with subsequent detection instruments. The micro-light imaging unit can capture the nanosecond-level transient processes such as the expansion of the plasma plume and the particle injection after femtosecond ablation, record the whole cycle dynamics from ablation to evolution to dissipation, and fill the observation blank of traditional systems for extremely short processes. The laser ablation sample introduction system with ultrafast imaging function provided by the embodiments of the present application can solve the problems of insufficient monitoring precision and poor analysis stability of samples in the prior art, and provides a new solution for efficient and accurate solid sample analysis technology, and provides a more reliable analysis tool for related scientific research and application fields. BRIEF DESCRIPTION OF DRAWINGS

[0044] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in

[0045] Figure 1 A schematic structural diagram of a coaxial imaging mode of a laser ablation sampling system with ultrafast imaging function according to an embodiment of the present application;

[0046] Figure 2 A schematic structural diagram of a side imaging mode of a laser ablation sampling system with ultrafast imaging function according to an embodiment of the present application;

[0047] Figure 3 A schematic step flow chart of a laser ablation sampling method with ultrafast imaging function according to an embodiment of the present application;

[0048] Figure 4 Evolution images of a 1064nm laser ablation multi-metallic ore at 630ns taken by a camera of a laser ablation sampling system with ultrafast imaging function according to an embodiment of the present application;

[0049] Figure 5 Evolution images of a 1064nm laser ablation multi-metallic ore at 660ns taken by a camera of a laser ablation sampling system with ultrafast imaging function according to an embodiment of the present application.

[0050] Correspondence between reference signs and component names in the drawings is as follows: Figures 1 to 2 Correspondence between reference signs and component names in the drawings is as follows:

[0051] 10 ablation cell, 20 laser pulse train emitting unit, 30 low-light imaging unit, 40 lens barrel, 50 focusing positioning unit, 60 objective lens, 70 visible light imaging camera;

[0052] 21 laser, 22 beam spot diameter controller, 23 shutter, 24 second dichroic mirror;

[0053] 31 first illumination unit, 32 half-mirror, 33 first magnifying lens, 34 first low-light imaging camera;

[0054] 35 second low-light imaging camera, 36 second magnifying lens, 37 collimator, 38 second illumination unit;

[0055] 51 first dichroic mirror, 52 focusing module, 53 moving platform, 54 control unit. DETAILED DESCRIPTION

[0056] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without one or more of these specific details.

[0057] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of the present application will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0058] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without one or more of these specific details.

[0059] As shown in Figures 1 to 2 According to the first aspect of the embodiments of the present application, a laser ablation solid sample injection system is provided, which comprises an ablation cell 10, a laser pulse string emission unit 20 and a micro-light imaging unit 30. The ablation cell 10 is used to accommodate a sample and output aerosol particles under the condition of flowing inert carrier gas. The laser pulse string emission unit 20 emits a laser beam, which is used to focus on the surface of the sample to sufficiently ablate the sample and generate nanoscale aerosol particles. The micro-light imaging unit 30 is arranged at the upper end of an optical barrel or parallel to the side surface of the ablation cell. The micro-light imaging unit 30 is used to record the evolution image of the ablation plume generated during the ablation process of the sample and output corresponding image data.

[0060] It can be understood that, in the present solution, the ablation cell 10 is made of transparent material in order to observe the sample. The micro-light imaging unit 30 can be selected from an ICMOS camera or an ICCD camera. The present system integrates an ultrafast imaging module with an ICMOS camera or an ICCD camera as the core, realizes real-time and accurate monitoring of the evolution of aerosol during the ablation process of the solid sample, and thus improves the analysis accuracy and stability. The present system supports coaxial imaging and side imaging, that is, the micro-light imaging unit 30 can collect images perpendicular to the ablation surface of the sample or collect images parallel to the direction of the ablation surface of the sample.

[0061] In the technical scheme, the ICMOS camera or the ICCD camera has a 0.3 ns ultra-short optical gate width, a time resolution of ≤0.5 ns and a spatial resolution of ≤0.5 μm, can capture the instantaneous dynamics of aerosol generation, diffusion and agglomeration, and can accurately capture the nanosecond-level transient process of the femtosecond laser ablation sample, such as the evolution of the plasma plume and the key dynamic information of the particle ejection trajectory, to provide unique data support for parameter optimization. The system applies the ICMOS camera or the ICCD camera to the real-time monitoring of aerosol in the laser ablation sampling system, and realizes the integration of the ICMOS camera or the ICCD camera with the femtosecond pulse train ablation and high-precision automatic focusing positioning. The real-time dynamic monitoring and parameter feedback mechanism brought by the ICMOS camera or the ICCD camera are the key to distinguishing the system from the traditional fixed parameter ablation sampling system, and effectively improve the problem of aerosol monitoring lag. At the same time, the system can cooperate with the ultraviolet femtosecond pulse train generation module and the beam spot regulation module to form a cooperative working system and break the limitation of the traditional system monitoring lag. For example Figure 4 Figure 2 shows the evolution image of the 1064 nm laser ablation of a multi-metal ore at 630 ns taken by the ICMOS camera. Figure 5 Figure 3 shows the evolution image of the 1064 nm laser ablation of a multi-metal ore at 660 ns taken by the ICMOS camera. It can be observed that the plasma has obvious diffusion phenomenon as time is pushed from 630 ns to 660 ns.

[0062] The present application breaks through the limitation of the traditional technology that cannot directly observe the ablation dynamics process by means of the ultra-high time and spatial resolution of the ICMOS camera or the ICCD camera, can associate the ablation transient image data with the composition analysis data output by the subsequent detection unit, and provides intuitive and key basis for in-depth research on the interaction mechanism of femtosecond laser and sample, optimization of ablation parameters and improvement of micro-area analysis precision, and is widely applicable to the micro-area element analysis field in the fields of geology, materials, biology and the like. By capturing the instantaneous evolution state of the aerosol in real time, the dynamic feedback of the parameters is realized, so that the analysis stability is significantly improved. The ultra-high resolution can clearly present the fine features such as the particle size distribution of the aerosol, and provide unique data support for the study of the ablation mechanism.

[0063] Figure 4 shows the evolution image of the 1064 nm laser ablation of a multi-metal ore at 660 ns taken by the ICMOS camera. Figure 1As shown, in an embodiment, the micro-light imaging unit 30 includes a first micro-light imaging camera 34, a half-mirror 32, and a first illumination unit 31. The first micro-light imaging camera 34 is arranged vertically above the ablation pool surface of the sample, at the end of the optical barrel, for coaxial ultrafast imaging or real-time imaging. The half-mirror 32 is arranged at a 45-degree angle and located in the optical path between the first micro-light imaging camera 34 and the ablation pool 10. The first illumination unit 31 emits a first illumination beam, which is reflected by the half-mirror 32 and focused coaxially with the laser beam on the sample surface. The light reflected by the sample surface is transmitted by the half-mirror 32 and enters the first micro-light imaging camera 34. The first micro-light imaging camera 34 has a first magnifying lens 33 with fixed or adjustable magnification, which is arranged between the ICMOS camera or the ICCD camera and the optical barrel, can further magnify the object image, and image on the sensitive end face of the camera.

[0064] In this technical solution, the coaxial imaging mode is adopted, i.e., the micro-light imaging unit 30 collects the image vertically above the ablation surface of the sample. The coaxial imaging has two functions. One is the real-time imaging function of the ordinary CCD camera, which ensures accurate finding and high-precision ablation sampling according to the pre-set sampling path, and the device is compact and easy to operate. The other is the high-time-resolution and high-spatial-resolution transient imaging function, which can accurately record the ablation plume morphology at a certain moment after laser ablation according to user needs, understand the laser ablation dynamics characteristics, and explain the physical and chemical mechanisms of the matrix effect and element fractionation effect.

[0065] In this technical solution, the half-mirror 32, also known as a beam splitter, a light splitter, etc., is an optical element that can divide the incident light beam into two parts, i.e., transmission and reflection. The first illumination unit 31 can only provide illumination light.

[0066] In an embodiment, the sample introduction system further includes a barrel 40 and an objective lens 60. The barrel 40 is arranged in the optical path between the first micro-light imaging camera 34 and the ablation pool 10, and the half-mirror 32 is arranged in the barrel 40. The objective lens 60 is arranged at the end of the barrel 40 close to the ablation pool 10.

[0067] It can be understood that the objective lens 60 microscopically magnifies the sample surface in the ablation pool 10, cooperates with the micro-light imaging camera, and enables the operator to clearly observe the microscopic morphology of the sample, specific mineral particles, or analysis area. This ensures that the laser beam can be accurately focused on the target position, avoids analysis errors caused by positioning deviation, and greatly improves the accuracy and reproducibility of the analysis.

[0068] In an implementable embodiment, the sample injection system further comprises a focusing positioning unit 50, the focusing positioning unit 50 comprising a focusing module 52, a first dichroic mirror 51, and a moving platform 53, the focusing module 52 being configured to focus on the sample surface and output focal position information; the first dichroic mirror 51 being obliquely arranged in the light path of the focusing light reflected by the sample surface, and the first dichroic mirror 51 being configured to reflect the light of the sample surface to the focusing module 52; the ablation cell 10 being arranged on the moving platform 53, and the moving platform 53 being configured to drive the ablation cell 10 and the sample to move according to the focal position information, so that the sample surface is automatically moved to the focal plane of the laser beam.

[0069] In this technical solution, the moving platform 53 is an XYZ motion stage, the focusing module 52 is composed of an image sensor, a digital signal processing module, a light source, and a piezoelectric ceramic, the image sensor is configured to collect the image of the sample surface, the digital signal processing module is configured to analyze the image to generate a control signal, and the piezoelectric ceramic is configured to deform to drive the XYZ motion stage to accurately displace to achieve rapid focusing.

[0070] It can be understood that the main types of dichroic mirrors include short-wave pass type and long-wave pass type, the short-wave pass type has high reflectivity to short-wavelength light (such as blue light and ultraviolet light) and high transmittance to long-wavelength light (such as red light and infrared light), and the long-wave pass type has high reflectivity to long-wavelength light and high transmittance to short-wavelength light. The dichroic mirror is usually composed of multiple layers of optical thin films, the thickness and refractive index of these thin films are precisely designed, the interference effect of light is utilized, and light of a specific wavelength range is efficiently reflected, while light of other wavelengths is efficiently transmitted. The common working angle is 45°, so as to conveniently separate or combine light beams in an optical system. In this solution, the laser beam, the first illumination light beam, and the imaging light are multiplexed on the same optical axis by adopting a coaxial integration architecture. The dichroic mirror and the half-transmission half-reflection mirror 32 are used to split and combine light, the coaxiality of focusing, ablation, and imaging on the sample is achieved, the accurate ablation of the femtosecond laser, the strict coincidence of the field of view of the ICMOS camera or the ICCD camera and the ablation area are ensured, the optical path calibration is simplified, and the spatial consistency and system compactness are improved.

[0071] In an implementable embodiment, the laser 21, the beam spot diameter controller 22, and the shutter 23 are arranged in sequence along the light path, the laser 21 is configured to emit a laser beam, the beam spot diameter controller 22 is configured to adjust the diameter of the laser beam, and the shutter 23 is configured to control the number and timing of the laser pulse train irradiated onto the sample. The second dichroic mirror 24 is further included, the second dichroic mirror 24 being obliquely arranged, and the second dichroic mirror 24 being configured to reflect the laser beam to the sample surface, and the second dichroic mirror 24 not affecting the reverse and forward transmission of the focusing laser and the first illumination light beam.

[0072] In the technical solution, the beam spot diameter controller 22 is composed of a zoom lens group, a mirror seat slider and a stepper motor. The motor drives the mirror seat slider to move the zoom lens group through a rotating shaft, changes the lens spacing to adjust the laser focal length, and then realizes flexible regulation and control of the beam spot size. The adjustable femtosecond pulse train and the precise positioning technology are coordinated with the monitoring function of the ICMOS camera or the ICCD camera to form a complete and efficient analysis system.

[0073] As shown in Figure 2 In a feasible implementation, the weak light imaging unit 30 includes a second weak light imaging camera 35, a second illumination unit 38 and a collimator 37. The second weak light imaging camera 35 is arranged in a direction parallel to the vertical side of the ablation cell for side imaging. The light inlet position of the second weak light imaging camera 35 is provided with a second magnifying lens 36 with fixed / adjustable magnification. The second illumination unit 38 and the second weak light imaging camera 35 are symmetrically distributed with respect to the ablation cell 10. The second illumination light beam emitted by the second illumination unit 38 penetrates the left end surface of the ablation cell 10, the ablation plume on the sample surface, the right end surface of the ablation cell 10, and then enters the second weak light imaging camera 35. The second illumination unit 38 includes a pulse modulation module configured to output the second illumination light beam as pulse illumination light. The collimator 37 is arranged at the light outlet of the second illumination unit 38. The collimator 37 is used to collimate the pulse illumination light into a parallel light beam.

[0074] It can be understood that the imaging mode in this scheme is a side imaging mode. The side imaging can realize larger spatial resolution imaging in a direction parallel to the laser ablation. Compared with coaxial imaging, the imaging space of side imaging is larger, and the ablation plume dynamic morphology is more coherent in the time domain and the spatial domain. However, it is necessary to use a coaxial ordinary CCD camera to realize real-time imaging, and a focusing module 52 to realize automatic focusing sampling of the laser. Figure 2 .

[0075] It can be understood that the ICMOS camera or the ICCD camera is connected with the control unit 54. Under the cooperation of the pulse illumination light (pulse width ≤10 ns), the time sequence matching with the femtosecond laser ablation is realized to ensure that the imaging and the ablation process are synchronized or delayed. Relying on the pulse illumination light, in combination with the synchronous pulse of the control unit 54 and the adjustable optical delay line, the synchronization or delay of the imaging and the femtosecond laser ablation is realized to accurately capture the nanosecond-level transient process such as plume expansion after initial ablation. Even under the condition of high-power LED continuous light illumination, ≤0.5 ns time resolution and ≤0.5 μm spatial resolution can be maintained to continuously track the dynamic characteristics such as ablation particle ejection and perform high-time and high-space resolution imaging. The two modes cover the needs of transient recording and continuous tracking respectively, and support micro-area analysis in multiple fields.

[0076] In a feasible implementation, a visible light imaging unit is further included, and the visible light imaging unit is arranged in a direction perpendicular to the sample ablation surface and is used to record an image of the sample ablation surface.

[0077] In the technical solution, the first micro-light imaging camera 34 can be used for real-time imaging when it works alone, which is beneficial for a user to quickly find a sampling point to be ablated, and then the first micro-light imaging camera 34 can be adjusted to ultrafast imaging when laser ablation sampling is performed.

[0078] The second micro-light imaging camera 35 can be used for ultrafast imaging when it works alone, and in this case, the first micro-light imaging camera 34 or a common camera is needed to cooperate. When the first micro-light imaging camera 34 cooperates, it can be used for real-time imaging or coaxial ultrafast imaging. When a common camera, for example, a CCD camera, is used to replace the first micro-light imaging camera 34, it can be used for real-time imaging.

[0079] It can be understood that the visible light imaging unit in the technical solution can be a visible light camera, which is arranged in a direction perpendicular to the sample ablation surface and is used to record an image of the sample ablation surface. In the technical solution, based on ICMOS or ICCD dynamic images (such as plume shape, particle distribution) and a time-space reference of a coaxial light path, ICP-MS / LIBS composition signals are associated, and a three-dimensional data closed loop of time, space and composition is constructed. ICP-MS and LIBS are two mainstream element composition analysis technologies, and compositions and signals thereof respectively refer to physical signals detected by instruments and used to determine element types and contents in a sample. The composition signal of ICP-MS (inductively coupled plasma mass spectrometry) is a mass spectrum signal, that is, an ion flow intensity (count) corresponding to different elements and isotopes detected by a mass spectrometer. The composition signal of LIBS (laser-induced breakdown spectroscopy) is a spectrum signal, that is, a characteristic wavelength light emitted when a sample is excited by a laser and a plasma cools down. Each element has a unique "spectrum fingerprint". Based on dynamic information such as plume asymmetry and particle aggregation, composition analysis deviation can be automatically corrected, and a whole-process cooperation from observation of an ablation process to analysis of a composition signal and then to feedback optimization of a parameter is realized.

[0080] In one feasible implementation, the sample introduction system further includes a control unit 54, which is signal-connected to the focusing module and the moving platform 53; and the control unit 54 is signal-connected to the low-light imaging unit 30 and the laser pulse train emission unit 20; the control unit 54 is configured to: receive the focus position information output by the focusing module, generate a first control signal based on the focus position information, and send the first control signal to the moving platform 53; and receive the image data of the evolution image output by the low-light imaging unit 30, generate a second control signal based on the image data of the evolution image, and send the second control signal to the laser pulse train emission unit 20; the moving platform 53 drives the ablation cell 10 and the sample to move according to the first control signal to achieve automatic focusing, and the laser pulse train emission unit 20 adjusts the emission parameters of the laser beam according to the second control signal.

[0081] In this technical solution, these image data are directly fed back to the control unit 54; the control unit 54 analyzes the image data and, based on the image analysis results, dynamically adjusts the laser beam parameters output by the laser pulse train emission unit 20, the carrier gas flow rate of the sample introduction system, etc., such as adjusting the sub-pulse interval and intensity ratio according to the aerosol particle size distribution to ensure the optimal ablation effect; finally, the aerosol is transported to the detection instrument by the inert carrier gas, and the control unit 54 stores the laser beam parameters, the imaging data of the ICMOS camera or ICCD camera, and the sample position information.

[0082] Throughout the process, real-time monitoring by an ICMOS or ICCD camera is maintained. The captured images allow for clear observation of subtle changes in the aerosols. Combined with the monitoring assistance of the focusing and positioning unit 50, the parameters of each module can be optimized in a timely manner. For example, when the ICMOS or ICCD camera detects uneven aerosol particle size distribution, the control unit 54 can immediately adjust the objective lens 60 of the beam spot diameter controller 22 to change the beam spot diameter, or adjust the sub-pulse parameters of the laser pulse train emission unit 20 to suppress elemental fractionation.

[0083] Leveraging the ultra-high resolution and rapid response capabilities of ICMOS or ICCD cameras, this system significantly improves analytical accuracy compared to traditional ablation sample introduction systems. It can accurately capture aerosol dynamics, providing a reliable basis for parameter adjustment, significantly shortening the analysis cycle, and meeting the high-precision analysis needs of solid samples in various fields. Furthermore, this system eliminates the need for complex auxiliary monitoring equipment, exhibits a high degree of integration, reduces equipment costs and process complexity, and significantly lowers raw material consumption and operating costs, making it suitable for large-scale application.

[0084] like Figure 3 As shown, according to a second aspect of the embodiments of this application, a method for introducing solid samples by laser ablation is proposed, the method comprising the following steps:

[0085] Step 81: emit a laser beam with set parameters, and focus the laser beam on the sample surface to ablate the sample;

[0086] Step 82: record the evolution image of the ablation plume during the ablation of the sample;

[0087] Step 83: generate a second control signal for optimizing the ablation effect according to the evolution image;

[0088] Step 84: adjust the emission parameters of the laser beam according to the second control signal.

[0089] The laser ablation solid sample injection method provided by the embodiments of the present application is applied to the laser ablation solid sample injection system of any of the above technical solutions, and therefore has all the beneficial effects of the laser ablation solid sample injection system of the above technical solutions.

[0090] As shown in Figure 3 It can be understood that the injection method provided by the embodiments of the present application first fixes the solid sample in the ablation cell 10, emits a laser beam through the laser pulse train emission unit 20, focuses the laser beam on the sample surface to ablate the sample, records the evolution image of the ablation plume during the ablation of the sample through the micro-light imaging unit 30, and outputs image data. The control unit 54 receives the image data and analyzes and processes the image data, generates a second control signal for optimizing the ablation effect according to the evolution image, and the laser pulse train emission unit 20 receives the second control signal and adjusts the emission parameters of the laser beam according to the second control signal.

[0091] It can be understood that the working process of the system is based on the monitoring function of the ICMOS camera or the ICCD camera: first, fix the solid sample on the sample stage of the ablation cell 10 through the focusing positioning unit 50 to adjust the position so that the focal point of the focusing module 52 coincides with the sample surface; then the laser pulse train emission unit 20 outputs a laser beam with set parameters, and after adjusting the beam spot diameter through the beam spot diameter controller 22, the laser beam is focused on the sample surface for ablation; during the ablation, the pulsed illumination light of the second illumination unit 38 works synchronously with the ICMOS camera or the ICCD camera, and the ICMOS camera or the ICCD camera records the evolution image of the ablation plume in real time.

[0092] The technology of the present application has a wide range of application fields, covering multiple advanced technologies and industries. In the field of geological exploration, the present application can capture the nanosecond-level evolution of the plasma plume of mineral denudation instantaneously by virtue of high time resolution, and by analyzing the plume shape and diffusion speed, accurately correlate the trace element distribution with the denudation dynamics characteristics, providing intuitive transient evidence for isotope dating and ore deposit genesis research. For example, clearly recording the synchronization process of U, Pb element release and plume expansion when zircon is denuded; in material science, the spatial resolution of the present application is ≤0.5 μm, and the single-photon-level weak light detection capability can track the particle ejection trajectory in real time when the semiconductor chip is denuded, clearly presenting the reaction details of the nanometer film interface, and assisting in chip defect tracing, such as observing the micro-area particle aggregation and plume asymmetry phenomenon when the film interlayer is peeled off; in biomedical research, the present application can synchronously capture the weak fluorescence signal and transient topographic changes generated by micro-area denudation of biological tissues, revealing the release dynamics of drug carriers in cells, for example, recording the corresponding relationship between the fluorescence intensity change and the denudation plume when drug nanoparticles are released from the inclusion body; in environmental monitoring, by means of time sequence synchronization function, the transient process of microplastic denudation is observed in real time, and the plume shape is used to distinguish different polymer components, providing dynamic analysis basis for pollutant tracing.

[0093] The system has broad application prospects in scientific research, medical treatment, industry and other fields. With the continuous development of ICMOS camera or ICCD camera, femtosecond laser and Internet of Things, artificial intelligence technology, market demand is rising. Especially in the fields of earth science, biomedicine, semiconductor manufacturing and automobile manufacturing, high-resolution denudation, ultrafast imaging monitoring and precise sampling function will become an important force to promote industry innovation. It is expected that in the application fields of micro-area in-situ element analysis, biological tissue detection and semiconductor quality monitoring, the system will greatly improve the analysis efficiency and accuracy, and accelerate the commercialization process of related technologies. In addition, with the continuous strengthening of intelligentization and high precision, the system will occupy an important position in the future market and bring great commercial potential to the industry development.

[0094] In the present application, the terms "first", "second", "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance; the term "multiple" refers to two or more, unless otherwise explicitly limited. The terms "mounting", "connecting", "connecting", "fixing" and the like should be broadly understood, for example, "connecting" can be fixed connection, or detachable connection, or integrally connected; "connected" can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0095] In the description of the application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or unit referred to must have a particular direction, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0096] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "a specific embodiment" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The above is only the preferred embodiment of the present application, and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A laser ablation sampling system with ultrafast imaging function, characterized in that, include: An ablation tank, the ablation tank being used to contain a sample; A laser pulse train emitting unit emits a laser beam, which is focused onto the sample surface to ablate the sample and generate aerosol particles. A low-light imaging unit is placed at a preset position in the ablation pool. The low-light imaging unit is used to record the evolution image of the ablation plume generated by the sample during the ablation process and output the corresponding image data. The low-light imaging unit includes: A first low-light imaging camera is arranged in a direction perpendicular to the ablated surface of the sample for coaxial imaging. A semi-transparent and semi-reflective mirror is tilted and located in the optical path between the first low-light imaging camera and the ablation pool; The first illumination unit emits a first illumination beam, which is reflected by the semi-transparent mirror and then focused coaxially with the laser beam onto the sample surface. The light reflected from the sample surface is transmitted through the semi-transparent mirror and then enters the first low-light imaging camera. The first magnifying lens is disposed at the lens of the first low-light imaging camera and is used to magnify the image.

2. The laser ablation sampling system with ultrafast imaging function according to claim 1, characterized in that, Also includes: The lens barrel is disposed in the optical path between the first low-light imaging camera and the ablation pool, and the semi-transparent and semi-reflective mirror is disposed inside the lens barrel; An objective lens is disposed at one end of the microscope tube near the ablation pool.

3. The laser ablation sample introduction system with ultrafast imaging function according to claim 1, characterized in that, It also includes a focus positioning unit, which includes: A focusing module, which is used to focus on the sample surface and output focus position information; The first dichroic mirror is tilted and disposed in the optical path of the focusing light reflected from the sample surface. The first dichroic mirror is used to reflect the focusing light from the sample surface to the focusing module. A mobile platform is provided, wherein the ablation tank is disposed on the mobile platform, and the mobile platform is configured to drive the ablation tank and the sample to move according to the focal position information, so that the sample surface is located on the focal plane of the laser beam.

4. The laser ablation sample introduction system with ultrafast imaging function according to claim 3, characterized in that, Also includes: The control unit is signal-connected to the focusing module and the moving platform; and the control unit is signal-connected to the low-light imaging unit and the laser pulse train emitting unit. The control unit is configured to: receive the focus position information, generate a first control signal based on the focus position information, and send the first control signal to the mobile platform; and receive the image data, generate a second control signal based on the image data, and send the second control signal to the laser pulse train emitting unit. The mobile platform drives the ablation tank and sample to move according to the first control signal to achieve automatic focusing, and the laser pulse train emission unit adjusts the emission parameters of the laser beam according to the second control signal.

5. The laser ablation sample introduction system with ultrafast imaging function according to claim 3, characterized in that, The laser pulse train emitting unit includes: A laser, a beam diameter controller, and a shutter are arranged sequentially along the optical path. The laser is used to emit the laser beam, the beam diameter controller is used to adjust the diameter of the laser beam, and the shutter is used to control the number and timing of the laser pulse train irradiating the sample.

6. The laser ablation sample introduction system with ultrafast imaging function according to claim 5, characterized in that, The laser pulse train emitting unit also includes: The second dichroic mirror is tilted and is used to reflect the laser beam onto the sample surface. The focusing light and the first illumination beam are transmitted forward and backward from the second dichroic mirror, respectively.

7. The laser ablation sample introduction system with ultrafast imaging function according to claim 1, characterized in that, The low-light imaging unit includes: The second low-light imaging camera, including an ICMOS camera, is arranged in a direction parallel to the ablated surface of the sample for side imaging. The second illumination unit is disposed on the side of the ablation pool away from the second low-light imaging camera. The second illumination beam emitted by the second illumination unit penetrates the first end face of the ablation pool, the ablation feather on the sample surface and the second end face of the ablation pool, and then enters the second low-light imaging camera. The second illumination unit includes a pulse modulation module, which is configured to output the second illumination beam as pulsed illumination light. A collimator is disposed at the light outlet of the second illumination unit, and the collimator is used to collimate the pulsed illumination light into a parallel beam.

8. The laser ablation sample introduction system with ultrafast imaging function according to claim 7, characterized in that, It also includes a visible light imaging unit, which is arranged in a direction perpendicular to the ablated surface of the sample, and is used to record images of the ablated surface of the sample.

9. A laser ablation sample introduction method with ultrafast imaging capability, characterized in that, Using the laser ablation sample introduction system with ultrafast imaging capability as described in any one of claims 1 to 8, the sample introduction method includes: A laser beam with set parameters is emitted and focused onto the sample surface for ablation. Record images of the evolution of the erosion plume during the sample erosion process; A second control signal for optimizing the ablation effect is generated based on the evolution image; The emission parameters of the laser beam are adjusted according to the second control signal.

Images