A laser-ultrasound microscopic imaging system, method and apparatus

Abstract

The application relates to a laser ultrasonic microscopic imaging system, method and device, wherein the laser ultrasonic microscopic imaging system comprises an excitation light source for emitting excitation light, a detection light source for emitting detection light, a first modulation module for modulating the deflection angle of the excitation light and reflecting the excitation light, a second modulation module for modulating the deflection angle of the detection light and reflecting the detection light, and an optical path converter, wherein the excitation light and the detection light form laser spots and detection spots on a sample surface, and a detection module and a data processing module are used to receive and process the detection light reflected from the sample surface to obtain an ultrasonic wave velocity image of the sample surface. The first modulation module and the second modulation module are used to high-speed modulate the excitation light and the detection light, so that the effect of rapidly measuring and imaging the ultrasonic wave velocity of the sample surface is achieved.

Description

Technical Field

[0001] This application relates to the field of laser ultrasound microscopy, and in particular to a laser ultrasound microscopy system, method and device. Background Technology

[0002] With the vigorous development of major fields such as aerospace, automobiles, shipbuilding, nuclear industry, and power, my country has also made tremendous progress in science and technology, national economy, and industrial manufacturing. Extreme working conditions such as high temperature and high pressure, high speed operation, and high load have become important characteristics of modern industry. For special metal materials, strict control of the crystal lattice orientation is one of the prerequisites for these materials to operate safely in extreme environments. For example, aircraft turbine blades, in order to ensure flight safety, require the blade to be in a single crystal state, and the crystal lattice orientation must be strictly consistent with the direction of centrifugal force during high-speed rotation.

[0003] However, extreme operating environments inevitably lead to partial lattice reorganization, causing the crystals to deviate from their original orientation, reducing the strength of the blades, and thus posing significant safety hazards. Employing rapid non-destructive testing techniques to inspect the structural health of crystal lattice orientation and grain size can largely eliminate these hazards. Laser ultrasonic technology, due to its unique advantage of non-contact testing, overcomes the key challenges faced by traditional contact testing techniques, making it more suitable for in-situ inspection of workpieces in extreme environments such as irregular shapes, high temperatures, and strong corrosion. Since the acoustic surface wave velocity is closely related to crystal structure and atomic arrangement, the crystal orientation distribution of the sample can be obtained by detecting the propagation speed of ultrasonic waves on the sample surface.

[0004] Traditional laser ultrasonic microscopy systems employ wavefront modulation, using a grating with a specific period to modulate the excitation source, generating directional ultrasonic waves on the workpiece surface. By extracting the frequency and wavelength of the ultrasonic signal, the velocity of the waves is obtained, and a two-dimensional scan of the sample surface yields an image of the sound velocity distribution. However, traditional laser ultrasonic microscopy systems use a three-axis motorized stage for scanning and imaging. Due to limitations in the stage's movement speed, the scanning speed is slow, making it difficult to achieve rapid imaging. Summary of the Invention

[0005] Therefore, it is necessary to provide a laser ultrasound microscopy system, method, and device to address the aforementioned technical problems.

[0006] In a first aspect, embodiments of this application provide a laser ultrasound microscopy imaging system, characterized in that the system comprises:

[0007] Excitation light source, used to emit excitation light;

[0008] A detection light source, used to emit detection light;

[0009] The first modulation module disposed in the output optical path of the excitation source is used to modulate the deflection angle of the excitation light and reflect the excitation light;

[0010] The second modulation module, disposed in the output optical path of the detection light source, is used to modulate the deflection angle of the detection light and reflect the detection light.

[0011] An optical path converter is used to convert the optical path of the excitation light so that the excitation light is transmitted to the sample surface to form a laser spot and to excite the sample surface to generate ultrasonic waves; and to convert the optical path of the probe light so that the probe light is transmitted to the sample surface to form a probe spot; and is also used to reflect the excitation light and the probe light transmitted to the sample surface.

[0012] The detection module is used to collect the detection light reflected from the sample surface and convert it into an electrical signal;

[0013] The data processing module is electrically connected to the detection module and is used to receive and process the electrical signal to obtain an ultrasonic wave velocity image of the sample surface.

[0014] In one embodiment, the first modulation module includes a first control unit and a first digital micromirror array; the second modulation module includes a second control unit and a second digital micromirror array.

[0015] The first control unit is used to control the deflection of the first digital micromirror array to modulate the deflection angle of the excitation light;

[0016] The second control unit is used to control the deflection of the second digital micromirror array to modulate the deflection angle of the probe light.

[0017] In one embodiment, the first control unit is used to control the deflection of the first digital micromirror array, and the second control unit is used to control the deflection of the second digital micromirror array, so that the excitation spot and the probe spot move synchronously on the sample surface.

[0018] In one embodiment, the first control unit is further configured to control the deflection of the first digital micromirror array, so that the excitation spot rotates at a preset angle with the detection spot as the center.

[0019] In one embodiment, the first control unit is further configured to control the first digital micromirror array to modulate the excitation light into a grating of a specific period, based on the sample.

[0020] In one embodiment, the excitation light source and the first modulation module further include:

[0021] A polarizer is used to filter the excitation light in a non-horizontal direction, ensuring that the polarization direction of the excitation light is horizontal.

[0022] A first beam expander is used to expand the excitation light to illuminate the first modulation module;

[0023] The first half-wave plate is used to adjust the polarization state of the excitation light.

[0024] In one embodiment, the detection light source and the second modulation module further include:

[0025] The second beam expander is used to expand the probe light to illuminate the second modulation module;

[0026] The second half-wave plate is used to adjust the polarization state of the probe light.

[0027] In one embodiment, the optical path converter includes a first beam splitter cube, a first lens, a second beam splitter cube, an objective lens, a dichroic mirror, and a third beam splitter cube.

[0028] The first beam-splitting cube is used to reflect the excitation light reflected from the first modulation module onto the sample surface;

[0029] The first lens is used to converge the excitation light reflected back from the first modulation module;

[0030] The second beam-splitting cube is used to reflect the probe light reflected from the second modulation module onto the sample surface;

[0031] The objective lens is used to focus the excitation light into an excitation spot and the probe light into a probe spot, so as to irradiate the sample surface;

[0032] The dichroic mirror is used to reflect the probe light and the excitation light reflected from the sample.

[0033] The third beam-splitting cube is used to reflect the probe light and transmit it to the detection module.

[0034] In one embodiment, the detection module includes a second lens, a blade, and a photodetector.

[0035] The second lens is used to converge the probe light reflected from the sample surface;

[0036] The blade is used to block half of the probe light reflected from the sample surface in order to measure the deflection of the probe light;

[0037] The photodetector is used to receive the detection light reflected from the sample surface and convert it into an electrical signal.

[0038] In one embodiment, the detection module further includes a third lens and an imaging device.

[0039] The third lens is used to converge the probe light and excitation light reflected from the sample surface;

[0040] The imaging device is used to receive the probe light and excitation light reflected from the sample surface, and to obtain images of the excitation spot and the probe spot.

[0041] Secondly, embodiments of this application also provide a method for ultrasonic wave velocity imaging of a crystal surface, the method comprising:

[0042] Control the excitation light source to emit excitation light and control the detection light source to emit detection light;

[0043] Control the first digital micromirror array and the second digital micromirror array to make the excitation spot and the probe spot formed on the sample surface move along a preset trajectory;

[0044] The detection module is controlled to collect the detection light reflected from the sample surface and convert it into an electrical signal;

[0045] The data processing module receives and processes the electrical signal to obtain an ultrasonic wave velocity image of the sample surface.

[0046] Thirdly, embodiments of this application also provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method described in the second aspect above.

[0047] The aforementioned laser ultrasonic microscopy imaging system, method, and apparatus modulate the deflection angle of the excitation light using a first modulation module and the deflection angle of the probe light using a second modulation module. This allows the excitation light to be transmitted to the sample surface, forming a laser spot and exciting the sample surface to generate ultrasonic waves. The probe light is also transmitted to the sample surface, forming a probe spot. The probe light is received and processed by a detection module and a data processing module to obtain an image of the ultrasonic wave velocity on the sample surface. This solves the problem in related technologies where scanning imaging using a three-axis motorized stage is limited by the stage's movement speed, making it difficult to achieve rapid imaging of the ultrasonic wave velocity on the sample surface. This application, through high-speed modulation of the excitation and probe light using the first and second modulation modules, achieves rapid measurement and scanning imaging of the ultrasonic wave velocity on the sample surface.

[0048] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0049] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0050] Figure 1 This is a structural block diagram of a laser ultrasound microscopy imaging system according to an embodiment of this application;

[0051] Figure 2 This is a structural block diagram of the first modulation module according to an embodiment of this application;

[0052] Figure 3 This is a structural block diagram of the second modulation module according to an embodiment of this application;

[0053] Figure 4 This is an image showing the distribution of the excitation and detection spots on the sample surface according to embodiments of this application;

[0054] Figure 5 This is an image showing the distribution of the excitation and detection light spots when the ultrasonic wave velocity of an anisotropic single crystal sample changes with the lattice direction, according to an embodiment of this application.

[0055] Figure 6 This is a structural block diagram of the detection module according to an embodiment of this application;

[0056] Figure 7 This is a structural block diagram of a laser ultrasound microscopy imaging system according to a preferred embodiment of this application;

[0057] Figure 8 This is a flowchart of a crystal surface ultrasonic wave velocity imaging method according to an embodiment of this application;

[0058] Figure 9 This is an internal structural diagram of a computer device according to an embodiment of this application.

[0059] Among them, 11-excitation source ； 12-Detection Light Source ； 13-First Modulation Module ； 14-Second Modulation Module ； 15-Optical Path Converter ； 16-Detection Module ； 17-Data Processing Module ； 131-First Control Unit ； 132-First Digital Micromirror Array ； 141-Second Control Unit； 142-Second Digital Micromirror Array ； 161-Second Lens ； 162-Blade ； 163-Photodetector ； 101-nanosecond laser ； 102-Polarizer ； 103-First Beam Expander ； 104-beamed cube ； 105-First Half-Wave Plate ； 106-Continuous Laser ； 107-Second beam expander ； 108-Second Half-Wave Plate ； 109-Second Beam Cube ； 110-First Lens ； 110-First Lens ； 111-Dichroic Mirror ； 112-Objective Lens ； 113-Third Beam Cube ； 114-Third Lens ； 115-CCD camera. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0061] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0062] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0063] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0064] This embodiment provides a laser ultrasound microscopy imaging system, such as Figure 1 The diagram shown is a structural diagram of a laser ultrasound microscopy imaging system according to an embodiment of this application. The system includes:

[0065] Excitation light source 11 is used to emit excitation light;

[0066] Detection light source 12 is used to emit detection light;

[0067] The first modulation module 13, disposed in the output optical path of the excitation light source 11, is used to modulate the deflection angle of the excitation light and reflect the excitation light;

[0068] The second modulation module 14, disposed on the output optical path of the detection light source 12, is used to modulate the deflection angle of the detection light and reflect the detection light.

[0069] The optical path converter 15 is used to convert the optical path of the excitation light so that the excitation light is transmitted to the sample surface to form a laser spot and to excite the sample surface to generate ultrasonic waves; and to convert the optical path of the probe light so that the probe light is transmitted to the sample surface to form a probe spot; and is also used to reflect the excitation light and the probe light transmitted to the sample surface.

[0070] Detection module 16 is used to collect the detection light reflected from the sample surface and convert it into an electrical signal;

[0071] The data processing module 17 is electrically connected to the detection module 16 and is used to receive and process the electrical signal to obtain an ultrasonic wave velocity image of the sample surface.

[0072] In this embodiment, the excitation source 11 can be a nanosecond laser with a wavelength of 1064nm, a continuously adjustable frequency of 1kHz-20kHz, and a laser pulse energy of 1mJ. The nanosecond laser emits excitation light as a source for generating ultrasonic waves on the sample surface. The detection source 12 can be a continuous-wave laser with a wavelength of 532nm and an average output power of 300mW. The continuous-wave laser emits detection light as a source for detecting ultrasonic waves on the sample surface. When the excitation light illuminates the first modulation module 13, the first modulation module 13 modulates the deflection angle of the excitation light and reflects it. When the detection light illuminates the second modulation module 14, the second modulation module 14 modulates the deflection angle of the detection light and reflects it. The excitation light reflected from the first modulation module 13 undergoes optical path conversion via an optical path converter, ultimately guiding the excitation light to the sample surface to form a laser spot. The excitation light instantaneously interacts with the sample surface to generate ultrasonic waves. The probe light reflected from the second modulation module 14 undergoes optical path conversion via an optical path converter, ultimately guiding the probe light to the sample surface to form a probe spot. The probe spot is located on one side of the excitation spot. The first modulation module 13 and the second modulation module 14 control the probe spot and the excitation spot to scan the sample surface according to a preset pattern, thereby achieving scanning of the sample. The optical path converter 15 is also used to reflect the excitation light and the probe light transmitted to the sample surface for transmission to the detection module 16 for processing. The detection module 16 collects the probe light carrying ultrasonic signals and performs photoelectric conversion, converting the probe light carrying ultrasonic signals into electrical signals. The data processing module 17 can obtain the wavelength and frequency of the ultrasonic waves on the sample surface by processing the electrical signal, calculate the ultrasonic wave velocity on the sample surface by multiplying the wavelength and frequency, and further process to obtain a two-dimensional image of the ultrasonic wave velocity on the sample surface.

[0073] In this embodiment, the first modulation module modulates the deflection angle of the excitation light and reflects it, while the second modulation module modulates the deflection angle of the probe light and reflects it. Further optical path conversion is performed on the excitation light and probe light, allowing the excitation light to be transmitted to the sample surface to form a laser spot and excite the sample surface to generate ultrasonic waves. The probe light is transmitted to the sample surface to form a probe spot. The first and second modulation modules perform high-speed modulation on the excitation and probe light, causing the probe spot and excitation spot to rapidly scan the sample surface according to a preset pattern. The probe light is received and processed by the detection module and data processing module to finally obtain an image of the ultrasonic wave velocity on the sample surface. This solves the problem in related technologies where scanning imaging using a three-axis electric displacement stage is limited by the stage's movement speed, making it difficult to quickly image the ultrasonic wave velocity on the sample surface. This application achieves rapid measurement and imaging of the ultrasonic wave velocity on the sample surface by using the first and second modulation modules to rapidly modulate the excitation and probe light and scan the sample surface.

[0074] In one embodiment, such as Figure 2 As shown, the first modulation module 13 includes a first control unit 131 and a first digital micromirror array 132; as Figure 3 As shown, the second modulation module 14 includes a second control unit 141 and a second digital micromirror array 142;

[0075] The first control unit 131 is used to control the deflection of the first digital micromirror array 132 to modulate the deflection angle of the excitation light;

[0076] The second control unit 141 is used to control the deflection of the second digital micromirror array 142 to modulate the deflection angle of the probe light.

[0077] In this embodiment, the first control unit 131 controls the deflection of the first digital micromirror array 132 to achieve rapid modulation of the deflection angle of the excitation light, and the second control unit 141 controls the deflection of the second digital micromirror array 142 to achieve rapid modulation of the deflection angle of the probe light. This avoids the problem of slow scanning speed in laser ultrasonic microscopy imaging systems in related technologies, speeds up the scanning speed of the sample, and achieves the effect of rapid measurement and imaging of ultrasonic wave velocity on the sample surface.

[0078] It should be noted that a polycrystalline material is composed of many grains. Within each grain, the lattice orientation is completely uniform, while the orientations of the grains themselves differ. Its properties are a statistical average of the properties of all the individual grains, meaning its properties are roughly the same in all directions. Therefore, polycrystalline materials exhibit isotropic properties. Isotropicity refers to the characteristic that the physical, chemical, and other properties of an object do not change with different directions; that is, the performance values ​​of an object measured in different directions are exactly the same. Therefore, when the sample is a polycrystalline sample, it is only necessary to perform scanning measurements in any direction of the polycrystalline sample.

[0079] In one embodiment, the first control unit 131 is used to control the deflection of the first digital micromirror array 132, and the second control unit 141 is used to control the deflection of the second digital micromirror array 142, so that the excitation spot and the detection spot move synchronously on the sample surface.

[0080] Specifically, the first control unit 131 controls the deflection of the first digital micromirror array 132 to modulate the emission direction of the excitation light. The excitation light is transmitted to the sample surface through the optical path converter 15 to form an excitation spot. The second control unit 141 controls the deflection of the second digital micromirror array 142 to modulate the emission direction of the probe light. The probe light is transmitted to the sample surface through the optical path converter 15 to form a probe spot. The first control unit 131 and the second control unit 141 synchronously control the excitation spot and the probe spot to move on the sample surface with a certain displacement to achieve scanning of the sample surface. The probe spot is kept fixed on one side of the excitation spot. The detection module 16 collects the ultrasonic signal generated after each movement of the excitation spot. The data processing module 17 processes and extracts the wavelength and frequency of the ultrasonic wave to finally obtain a two-dimensional image of the ultrasonic wave velocity on the polycrystalline sample surface.

[0081] It should be noted that the atomic density varies on different crystal planes and directions in a single crystal, resulting in different interatomic bonding forces and thus different properties in different directions. Anisotropy refers to the change in all or part of a substance's chemical, physical, and other properties as the direction changes, exhibiting different properties in different directions. Therefore, when the sample is a single crystal sample, it is necessary to perform scanning measurements on the single crystal sample in different directions.

[0082] In one embodiment, the first control unit 131 is further configured to control the first digital micromirror array 132 to deflect, so that the excitation spot rotates at a preset angle with the detection spot as the center.

[0083] In this embodiment, the first control unit 131 controls the deflection of the first digital micromirror array 132, causing the excitation spot to rotate 360 ​​degrees around the detection spot at a preset angle. During this rotation, the second control unit 141 keeps the detection spot stationary, ensuring data accuracy. The detection module 16 collects the ultrasonic signal generated after each rotation of the excitation spot. The data processing module 17 processes and extracts the wavelength and frequency of the ultrasonic waves, ultimately obtaining a curve showing the variation of ultrasonic wave velocity and sample angle in different crystal orientations of the anisotropic single crystal sample.

[0084] It should be noted that traditional laser ultrasonic velocity detection systems use wavefront modulation to modulate the excitation source with a grating of a specific period. However, when detecting materials with large differences in sound velocity, it is necessary to change the grating to one with a different period.

[0085] In one embodiment, the first control unit 131 is further configured to control the first digital micromirror array 132 to modulate the excitation light into a grating with a specific period, based on the sample.

[0086] In this embodiment, the first digital micromirror array 132 is directly controlled by the first control unit 131 to modulate the excitation light into a grating with a specific period, thus eliminating the need to replace gratings with different periods and simplifying operation. After being modulated into a grating with a specific period, the excitation light is reflected and irradiated onto the sample surface by the optical path converter 15, generating directionally propagating ultrasonic waves on the sample surface. The wavelength of the ultrasonic waves is equal to the period of the grating on the sample surface, and the frequency can be obtained through Fourier transform. By extracting the frequency and wavelength of the ultrasonic signal, the velocity of the ultrasonic waves on the sample surface can be obtained.

[0087] In one embodiment, the excitation light source 11 and the first modulation module 13 further include:

[0088] A polarizer is used to filter the excitation light in a non-horizontal direction, ensuring that the polarization direction of the excitation light is horizontal.

[0089] A first beam expander is used to expand the excitation light to illuminate the first modulation module;

[0090] The first half-wave plate is used to adjust the polarization state of the excitation light.

[0091] Specifically, the excitation light emitted by the excitation source 11 passes sequentially through the polarizer, the first beam expander, and the first half-wave plate before finally illuminating the first modulation module 13. The first beam expander consists of two lenses.

[0092] In one embodiment, the detection light source 12 and the second modulation module 14 further include:

[0093] The second beam expander is used to expand the probe light to illuminate the second modulation module;

[0094] The second half-wave plate is used to adjust the polarization state of the probe light.

[0095] Specifically, the detection light emitted by the detection light source 12 passes sequentially through the second beam expander and the second half-wave plate before finally illuminating the second modulation module 14. The second beam expander consists of two lenses.

[0096] In one embodiment, the optical path converter includes a first beam splitter cube, a first lens, a second beam splitter cube, an objective lens, a dichroic mirror, and a third beam splitter cube.

[0097] The first beam-splitting cube is used to reflect the excitation light reflected from the first modulation module onto the sample surface;

[0098] The first lens is used to converge the excitation light reflected back from the first modulation module;

[0099] The second beam-splitting cube is used to reflect the probe light reflected from the second modulation module onto the sample surface;

[0100] The objective lens is used to focus the excitation light into an excitation spot and the probe light into a probe spot, so as to irradiate the sample surface;

[0101] The dichroic mirror is used to reflect the probe light and the excitation light reflected from the sample.

[0102] The third beam-splitting cube is used to reflect the probe light and transmit it to the detection module.

[0103] Specifically, the excitation light reflected from the first modulation module 13 passes sequentially through the first beam splitter cube, the first lens, the second beam splitter cube, the dichroic mirror, and the objective lens before finally reaching the sample surface to form a laser spot. The probe light reflected from the second modulation module 14 passes sequentially through the second beam splitter cube, the dichroic mirror, and the objective lens before finally reaching the sample surface to form a probe spot. The probe light and the excitation light reflected from the sample then pass sequentially through the objective lens, the dichroic mirror, and the third beam splitter cube for reflection before reaching the detection module for detection.

[0104] In one embodiment, such as Figure 4 The detection module 16 includes a second lens 161, a blade 162, and a photodetector 163.

[0105] The second lens 161 is used to converge the probe light reflected from the sample surface;

[0106] The blade 162 is used to block half of the probe light reflected from the sample surface in order to measure the deflection of the probe light.

[0107] The photodetector 163 is used to receive the detection light reflected from the sample surface and convert it into an electrical signal.

[0108] Specifically, this embodiment employs a blade-edge detection method to detect ultrasonic signals. The second lens 161, the blade 162, and the photodetector 163 constitute a blade-edge detector, a detection method used to detect beam deflection. Since the probe light, after being focused on the sample surface, experiences surface vibrations caused by the ultrasonic waves, the reflected probe light deflects. The deflection angle reflects information such as the amplitude and phase of the ultrasonic waves. Therefore, the blade-edge detection method can effectively detect the deflection of the probe light and obtain the waveform of the ultrasonic waves. The blade-edge detector uses a blade to block half of the probe light. When the probe light deflects, the portion transmitted through the blade changes, and the photodetector detects this change in amplitude.

[0109] In one embodiment, the detection module further includes a third lens and an imaging device.

[0110] The third lens is used to converge the probe light and excitation light reflected from the sample surface;

[0111] The imaging device is used to receive the probe light and excitation light reflected from the sample surface, and to obtain images of the excitation spot and the probe spot.

[0112] Specifically, the probe light and excitation light reflected from the sample surface are transmitted to the third lens via the optical path converter 15. The third lens converges the probe light and the excitation light, which are then received by the imaging device and processed to obtain images of the excitation spot and the probe spot. Optionally, in one embodiment, the imaging device can be a CCD camera. Figure 5 This is an image showing the distribution of the excitation spot and the probe spot on the sample surface. Figure 6 To detect the distribution images of the excitation spot and the detection spot when the ultrasonic wave velocity of an anisotropic single crystal sample changes with the lattice direction.

[0113] This application also provides a specific embodiment of a laser ultrasound microscopy imaging system, such as... Figure 7 As shown, Figure 7 This is a schematic diagram of the structure of a laser ultrasound microscopy system in a preferred embodiment.

[0114] Nanosecond laser 101 emits excitation light, which passes sequentially through polarizer 102, first beam expander 103, first beam splitter cube 104, and first half-wave plate 105 to irradiate the first digital micromirror array 132; continuous laser 106 emits probe light, which passes sequentially through second beam expander 107, second half-wave plate 108, and second beam splitter cube 109 to irradiate the second digital micromirror array 142. The first control unit 131 controls the first digital micromirror array 132 to deflect, thereby modulating the deflection angle of the excitation light. The excitation light is then modulated into a grating with a specific period according to the sample, and reflected. The reflected excitation light sequentially passes through the first beam splitter cube 104, the first lens 110, the second beam splitter cube 109, the dichroic mirror 111, and the objective lens 112, ultimately reaching the sample surface to form a laser spot and exciting the sample surface to generate ultrasonic waves. The second control unit 141 controls the second digital micromirror array 142 to deflect, thereby modulating the deflection angle of the probe light, and reflects the probe light. The reflected probe light sequentially passes through the second beam splitter cube 109, the dichroic mirror 111, and the objective lens 112, ultimately reaching the sample surface to form a probe spot. The probe spot is located on one side of the excitation spot. The first control unit 131 and the second control unit 141 control the probe spot and the excitation spot to scan the sample surface according to a preset pattern, thereby achieving the scanning of the sample. The probe light transmitted to the sample surface is reflected and sequentially passes through objective lens 112, dichroic mirror 111, third beam splitter cube 113, second lens 161, and blade 162, before being received by photodetector 163. Photodetector 163 converts the light into an electrical signal, which is then received and processed by data processing module 17 to obtain an image of the ultrasonic wave velocity on the sample surface. The probe light and excitation light transmitted to the sample surface are also reflected and sequentially pass through objective lens 112, dichroic mirror 111, third beam splitter cube 113, and third lens 114, before being received by CCD camera 115 to obtain images of the excitation and probe light spots.

[0115] In this embodiment, the first control unit 131 controls the deflection of the first digital micromirror array 132 to modulate the deflection angle of the excitation light and reflect the excitation light. The second control unit 141 controls the deflection of the second digital micromirror array 142 to modulate the deflection angle of the probe light and reflect the probe light. Further optical path conversion is performed on the excitation light and the probe light, so that the excitation light is transmitted to the sample surface to form a laser spot and excites the sample surface to generate ultrasonic waves. The probe light is transmitted to the sample surface to form a probe spot. The first control unit 131 and the second control unit 141 control the probe spot and the excitation spot to scan the sample surface according to a preset pattern, thereby scanning the sample. The photodetector 163 and the data processing module 17 receive and process the probe light to obtain an image of the ultrasonic wave velocity of the sample surface. This solves the problem in related technologies where scanning imaging using a three-axis electric displacement stage is limited by the movement speed of the displacement stage, making it difficult to quickly image the ultrasonic wave velocity of the sample surface. In this application, the excitation light and the probe light are rapidly modulated by controlling the deflection of the first digital micromirror array by the first control unit and the deflection of the second digital micromirror array by the second control unit, thereby scanning the sample surface and achieving the effect of rapid measurement and imaging of the ultrasonic wave velocity of the sample surface.

[0116] This application also provides a method for ultrasonic wave velocity imaging of a crystal surface, such as... Figure 8 As shown, the method includes the following steps:

[0117] Step S801: Control the excitation light source to emit excitation light and control the detection light source to emit detection light;

[0118] Step S802: Control the first digital micromirror array and the second digital micromirror array so that the excitation spot and the detection spot formed on the sample surface move along a preset trajectory;

[0119] Specifically, the excitation light illuminates the first modulation module, and the first control unit controls the first digital micromirror array to deflect, modulating the deflection angle of the excitation light and reflecting it. The excitation light undergoes optical path conversion through an optical path converter, ultimately guiding it to the sample surface to form a laser spot. The excitation light interacts instantaneously with the sample surface to generate ultrasonic waves. The probe light illuminates the second modulation module, and the second control unit controls the second digital micromirror array to deflect, modulating the deflection angle of the probe light and reflecting it. The probe light undergoes optical path conversion through an optical path converter, ultimately guiding it to the sample surface to form a probe spot. The movement of the excitation spot and probe spot on the sample surface along a preset trajectory specifically includes: controlling the deflection of the first digital micromirror array through the first control unit and the deflection of the second digital micromirror array through the second control unit, causing the excitation spot and probe spot to move synchronously on the sample surface; or controlling the deflection of the first digital micromirror array through the first control unit, causing the excitation spot to rotate around the probe spot at a preset angle.

[0120] Step S803: Control the detection module to collect the detection light reflected from the sample surface and convert it into an electrical signal;

[0121] During the process of controlling the first digital micromirror array and the second digital micromirror array to make the excitation spot and the detection spot formed on the sample surface move along a preset trajectory, each time the excitation spot moves, the detection module is controlled to collect the detection light reflected back from the sample surface and convert it into an electrical signal.

[0122] Step S804: Control the data processing module to receive and process the electrical signal to obtain an ultrasonic wave velocity image of the sample surface.

[0123] In this embodiment, a first control unit controls the deflection of the first digital micromirror array to modulate the deflection angle of the excitation light and reflect the excitation light. A second control unit controls the deflection of the second digital micromirror array to modulate the deflection angle of the probe light and reflect the probe light. Further optical path conversion is performed on the excitation light and the probe light, so that the excitation light is transmitted to the sample surface to form a laser spot and excites the sample surface to generate ultrasonic waves. The probe light is transmitted to the sample surface to form a probe spot. The first and second control units perform high-speed modulation on the excitation light and the probe light, controlling the probe spot and the excitation spot to scan the sample surface along a preset trajectory. The probe light is received and processed by a photodetector and a data processing module to obtain an image of the ultrasonic wave velocity of the sample surface. This application solves the problem in related technologies where scanning imaging using a three-axis electric displacement stage is limited by the movement speed of the displacement stage, making it difficult to quickly image the ultrasonic wave velocity of the sample surface. It achieves the effect of rapid measurement and imaging of the ultrasonic wave velocity of the sample surface.

[0124] In one embodiment, a computer device is provided, which may be a terminal, and its internal structure diagram may be as follows: Figure 9 As shown, the computer device includes a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, or other technologies. When executed by the processor, the computer program implements a method for ultrasonic wave velocity imaging of a crystal surface. The display screen can be a liquid crystal display (LCD) or an e-ink display. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0125] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0126] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A laser ultrasound microscopy imaging system, characterized in that, The system includes: Excitation light source, used to emit excitation light; A detection light source, used to emit detection light; A first modulation module disposed in the output optical path of the excitation light source is used to modulate the deflection angle of the excitation light and reflect the excitation light; the first modulation module includes a first control unit and a first digital micromirror array; the first control unit is used to control the deflection of the first digital micromirror array to modulate the deflection angle of the excitation light; A second modulation module disposed in the output optical path of the detection light source is used to modulate the deflection angle of the detection light and reflect the detection light; the second modulation module includes a second control unit and a second digital micromirror array; the second control unit is used to control the deflection of the second digital micromirror array to modulate the deflection angle of the detection light; An optical path converter is used to convert the optical path of the excitation light, so that the excitation light is transmitted to the sample surface to form an excitation spot and excites the sample surface to generate ultrasonic waves; and to convert the optical path of the probe light, so that the probe light is transmitted to the sample surface to form a probe spot; the probe spot is located on one side of the excitation spot, and the first modulation module and the second modulation module control the probe spot and the excitation spot to scan the sample surface according to a preset pattern; when the sample is a polycrystalline sample, the first control unit is used to control the deflection of the first digital micromirror array, and the second control unit is used to control the deflection of the second digital micromirror array, so that the excitation spot and the probe spot move synchronously on the sample surface; when the sample is a single-crystal sample, the first control unit is also used to control the deflection of the first digital micromirror array, so that the excitation spot rotates around the probe spot at a preset angle; The optical path converter is also used to reflect the excitation light and the probe light transmitted to the sample surface; The detection module is used to collect the ultrasonic signal generated after each movement of the excitation spot and convert it into an electrical signal. The data processing module is electrically connected to the detection module and is used to receive and process the electrical signal, obtain the wavelength and frequency of the ultrasonic wave, and obtain an ultrasonic wave velocity image of the sample surface based on the wavelength and frequency.

2. The laser ultrasonic microscopy imaging system according to claim 1, characterized in that, The first control unit is also configured to control the first digital micromirror array to modulate the excitation light into a grating with a certain period, based on the sample.

3. The laser ultrasonic microscopy imaging system according to claim 1, characterized in that, The excitation light source and the first modulation module also include: A polarizer is used to filter the excitation light in a non-horizontal direction, ensuring that the polarization direction of the excitation light is horizontal. A first beam expander is used to expand the excitation light to illuminate the first modulation module; The first half-wave plate is used to adjust the polarization state of the excitation light.

4. The laser ultrasonic microscopy imaging system according to claim 1, characterized in that, The detection light source and the second modulation module also include: The second beam expander is used to expand the probe light to illuminate the second modulation module; The second half-wave plate is used to adjust the polarization state of the probe light.

5. The laser ultrasonic microscopy imaging system according to claim 1, characterized in that, The optical path converter includes a first beam splitter cube, a first lens, a second beam splitter cube, an objective lens, a dichroic mirror, and a third beam splitter cube. The first beam-splitting cube is used to reflect the excitation light reflected from the first modulation module onto the sample surface; The first lens is used to converge the excitation light reflected back from the first modulation module; The second beam-splitting cube is used to reflect the probe light reflected from the second modulation module onto the sample surface; The objective lens is used to focus the excitation light into an excitation spot and the probe light into a probe spot, so as to irradiate the sample surface; The dichroic mirror is used to reflect the probe light and the excitation light reflected from the sample. The third beam-splitting cube is used to reflect the probe light and transmit it to the detection module.

6. The laser ultrasonic microscopy imaging system according to claim 1, characterized in that, The detection module includes a second lens, a blade, and a photodetector. The second lens is used to converge the probe light reflected from the sample surface; The blade is used to block half of the probe light reflected from the sample surface in order to measure the deflection of the probe light; The photodetector is used to receive the detection light reflected from the sample surface and convert it into an electrical signal.

7. The laser ultrasonic microscopy imaging system according to claim 6, characterized in that, The detection module also includes a third lens and an imaging device. The third lens is used to converge the probe light and excitation light reflected from the sample surface; The imaging device is used to receive the probe light and excitation light reflected from the sample surface, and to obtain images of the excitation spot and the probe spot.

8. A method for imaging the velocity of ultrasonic waves on a crystal surface, applied to a laser ultrasonic microscopy system as described in any one of claims 1 to 7, characterized in that, The method includes: Control the excitation light source to emit excitation light and control the detection light source to emit detection light; The system controls the first and second digital micromirror arrays to make the excitation and detection spots formed on the sample surface move along a preset trajectory. When the sample is a polycrystalline sample, the first control unit controls the deflection of the first digital micromirror array, and the second control unit controls the deflection of the second digital micromirror array, so that the excitation and detection spots move synchronously on the sample surface. When the sample is a single-crystal sample, the first control unit also controls the deflection of the first digital micromirror array, so that the excitation spot rotates around the detection spot at a preset angle. The detection module is controlled to collect the ultrasonic signal generated each time the excitation spot moves, and convert it into an electrical signal. The data processing module receives and processes the electrical signal to obtain the wavelength and frequency of the ultrasonic wave, and obtains an ultrasonic wave velocity image of the sample surface based on the wavelength and frequency.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, The processor implements the method of claim 8 when executing the computer program.

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