Flattop beam uniformity optimization and centroid position control feedback system and method

Abstract

The invention discloses a flat-topped beam uniformity optimization and centroid position control feedback system and method, and belongs to the technical field of automatic feedback control. The problems that an optical element needs to be frequently adjusted in a traditional method, and the same accuracy and reaction speed are difficult to achieve in a method of manually adjusting the optical element in an optical path are solved. The closed-loop feedback system comprises a laser, a first lens, a second lens, a first reflector, a second reflector, a third reflector, a spatial light modulator, a polarization beam splitter (PBS), an achromatic lens, a fourth reflector, a camera, a computer, a high-voltage amplifier, piezoelectric ceramics and a lambda / 2 wave plate. The position and intensity distribution of the flat-topped light beam are dynamically adjusted through a real-time image processing technology, and an experimenter does not need to manually adjust optical elements in a light path. The method is more flexible and higher in precision. The innovation not only helps to improve the accuracy and efficiency of the experiment, but also provides important support for smooth development and development of the experiment.

Description

Technical Field

[0001] The present invention belongs to the technical field of automatic feedback control, and particularly relates to a feedback system and method for optimizing the uniformity of a flat-top beam and controlling the centroid position. Background Art

[0002] In quantum optical experiments, flat-top beams play a crucial role. To ensure the accuracy of experimental results, extremely strict requirements are imposed on the intensity uniformity and position stability of flat-top beams. However, due to various interference factors in the actual experimental system, the generated flat-top beams may change in terms of intensity, uniformity, and position during the experiment, which has an adverse impact on the experimental results. Summary of the Invention

[0003] Aiming at the problems that traditional methods require frequent adjustment of optical elements, and it is difficult to achieve the same precision and response speed by manually adjusting the optical elements in the optical path, the present invention provides a feedback system and method for optimizing the uniformity of a flat-top beam and controlling the centroid position.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A closed-loop feedback system for optimizing the uniformity of a flat-top beam and controlling the centroid position, the system comprising: a laser, a first lens, a second lens, a first mirror, a second mirror, a third mirror, a spatial light modulator, a polarization beam splitter prism PBS, an achromatic lens, a fourth mirror, a camera, a computer, a high-voltage amplifier, a piezoelectric ceramic, and a λ / 2 wave plate;

[0006] The laser generates laser light, which, after passing through the first lens and the second lens respectively, is reflected by the first mirror into the spatial light modulator. Then, after the spatial light modulator modulates the wavefront of the incident laser light, the laser light is emitted to the second mirror. The second mirror reflects the laser light to the third mirror, and the third mirror reflects the laser light to the λ / 2 wave plate corresponding to the wavelength to change the polarization state of the laser light. The laser light reaches the polarization beam splitter prism PBS after passing through the wave plate. The laser light after passing through the polarization beam splitter prism PBS is incident on the achromatic lens and then emitted to the fourth mirror. A piezoelectric ceramic is installed on the fourth mirror mount for adjusting the position of the light beam; the piezoelectric ceramic is connected to the high-voltage amplifier, and the high-voltage amplifier is connected to the computer.

[0007] Furthermore, it also includes a graphical user interface (GUI) that adjusts multiple key parameters (such as exposure time, frame rate, gain, etc.) to optimize the working state of the camera and adapt to different experimental requirements. The graphical user interface supports real-time monitoring of the data collected by the camera, facilitating users to adjust the intensity distribution and uniformity of the light beam to ensure that the final light beam meets the experimental requirements. This graphical user interface enhances the flexibility and operational convenience of the system; it is designed to be simple and intuitive, and users can quickly modify parameters by adjusting the input boxes in the interface, view image changes in real time, and perform debugging.

[0008] A closed-loop feedback method for optimizing the uniformity of a flat-top beam and controlling the centroid position includes the following steps:

[0009] Step 1, generate an ideal target image corresponding to the target flat-top beam, use the beam shaping algorithm MixedRegionAmplitude Freedom (MRAF) to generate a corresponding computer-generated hologram (CGH) image, load the CGH image onto a spatial light modulator (SLM), and then modulate the wavefront of the incident light through the spatial light modulator (SLM) to generate a flat-top beam at the focal plane of the lens.

[0010] Step 2, accurately place the camera at the focal plane of the lens to ensure that the light beam is perpendicularly incident on the center of the camera; ensure that the camera captures the accurately shaped light beam image, use the Python programming language to achieve control of the camera, automatically complete the image acquisition process of the flat-top beam, and perform recognition and analysis on the image.

[0011] Step 3, when the flat-top beam gradually stabilizes, set a recognition threshold before image recognition to ensure accurate identification of the flat-top beam region; set the recognition region to a specific geometric shape that is consistent with the geometric shape of the flat-top beam; after marking the flat-top beam region with a border of a certain color, calculate the coordinates of its geometric center, set this coordinate as the geometric center reference, and mark this geometric center with a specific symbol for reference.

[0012] Step 4, set a distance threshold to define the maximum acceptable offset of the flat-top beam; when the position of the light beam deviates beyond this threshold, the system will accurately calculate the specific offset of the centroid of the flat-top beam through image recognition technology and feedback this value to the computer; determine whether the deviation exceeds the distance threshold; if it does not exceed the distance threshold, continue monitoring and recognition; if it exceeds the distance threshold, the computer will control the high-voltage amplifier to output a voltage signal, and the piezoelectric ceramic will achieve a small displacement of the mirror mount by responding to the voltage signal, thereby accurately adjusting the direction and position of the light beam to restore the flat-top beam to the predetermined position.

[0013] Step 5, after the position calibration is completed, perform intensity analysis on the flat-top beam image captured by the camera; divide the flat-top beam image into multiple sub-regions, calculate the average value of the pixel values in each sub-region, and further calculate the standard deviation of the average values of all sub-regions, expressed as:

[0014]

[0015] where: σ is the standard deviation; N is the number of sub-regions; x n is the average pixel value of each sub-region; μ is the average value of all sub-region values, and the calculation formula is:

[0016] Step 6, reconstruct the target map of the flat-top beam so that the pixel value of each sub-region is adjusted according to the global average value and the uniformity deviation;

[0017] X re = X target *(ratio * 0.7 + 1)

[0018] where, X re represents the pixel value of each sub-region in the reconstructed target map; X target represents the pixel value in the initial ideal target image; ratio is the difference between the average value of all sub-regions and the pixel value of a certain sub-region, and then divided by the average value of all sub-regions;

[0019] Step 7, after the reconstruction of the target map is completed, the new target map will be input into the algorithm to generate a new flat-top beam; subsequently, capture the beam image through the camera and perform intensity analysis, and continue to reconstruct the target map; repeat the cycle until the uniformity of the flat-top beam reaches the preset requirement, and terminate the optimization process.

[0020] Furthermore, the recognition threshold in step 3 should be able to cover the entire flat-top beam region and effectively avoid misidentifying low-intensity stray light as part of the beam.

[0021] Furthermore, the output voltage V PID of the high-voltage amplifier in step 4 is calculated according to the position deviation e(t), expressed as:

[0022] e(t) = x ref – x(t)

[0023] where, e(t) is the deviation between the target centroid position x ref and the actual centroid position x(t);

[0024] The output of the high-voltage amplifier is expressed as:

[0025]

[0026] Where: K p is the proportional gain, which determines the immediate response of the high-voltage amplifier to the position deviation; K i is the integral gain, which processes the accumulated deviation; K d is the derivative gain, which processes the rate of change of the position deviation; τ is a variable time identifier used in the calculation of the integral from the start to the current time t, where t is the current time, which is a definite time point.

[0027] Furthermore, the specific method for the piezoelectric ceramic to achieve the micro-displacement of the mirror mount in step 4 is as follows:

[0028] The displacement of the mirror mount is linearly related to the applied voltage, expressed as:

[0029] Δx = α·V PID

[0030] Where: Δx represents the displacement of the piezoelectric ceramic; α is the displacement constant of the piezoelectric ceramic, with the unit of μm / V, representing the displacement caused by each volt of voltage; V PID is the output voltage signal.

[0031] When the piezoelectric ceramic receives the voltage signal V PID it will drive the mirror mount to generate a small physical displacement. This displacement precisely controls the angle and position of the mirror or other optical elements, thereby achieving the adjustment of the light beam. The system will adjust the voltage signal output by the high-voltage amplifier to the voltage range suitable for driving the piezoelectric ceramic, enabling the light beam position to be corrected quickly and precisely.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] The present invention generates a flat-top light beam with an arbitrary geometric shape through the MRAF algorithm, and then controls the light beam position in real time through closed-loop feedback. This not only improves the stability and automation level of the system, but also shortens the adjustment time and enhances the system response speed. In addition, the present invention can dynamically adjust the centroid position of the light beam without changing the experimental optical path, avoiding the trouble of frequently adjusting optical elements in the traditional method. This system can control the accuracy of the light beam at the micron level, and automatically adjust the light beam position and intensity distribution through a feedback mechanism to adapt to the changes in different experimental environments, ensuring that the quality of the light beam always reaches a high standard. Compared with the prior art, the high precision and high efficiency of this system make it more suitable for quantum optical experiments and precision measurements with extremely high requirements for light beams.

[0034] Through closed-loop feedback control and real-time image processing technology, this system realizes high-precision flat-top beam generation, position control, and uniformity optimization. First, the system generates a flat-top beam through the MRAF algorithm, and uses a camera to capture the beam image in real time, calculating the centroid position and intensity distribution of the beam. When detecting beam position deviation or excessive non-uniformity, the computer controls the high-voltage amplifier to adjust the piezoelectric ceramic to restore the stability and uniformity of the beam. By continuously iterating the reconstruction and optimization of the target image, the system can ensure that the flat-top beam meets the experimental requirements in terms of intensity, position, and uniformity, thus improving the experimental accuracy and efficiency. This system provides strong support for high-precision applications such as quantum optical experiments. Description of the Drawings

[0035] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0036] Figure 1 It is a schematic diagram of the system device of the present invention;

[0037] Figure 2 It is a flowchart of position monitoring within the system;

[0038] Figure 3 It is a flowchart of uniformity monitoring within the system;

[0039] Figure 4 It is a schematic diagram of the image recognition process;

[0040] Figure 5 It is a schematic diagram of the graphical user interface.

[0041] Reference numerals: 1. Laser; 2. First lens; 3. Second lens; 4. First mirror; 5. Second mirror; 6. Third mirror; 7. Spatial light modulator; 8. Polarizing beam splitter prism PBS; 9. Achromatic lens; 10. Fourth mirror; 11. Camera; 12. Computer; 13. High-voltage amplifier; 14. Piezoelectric ceramic; 15. λ / 2 wave plate. Detailed Embodiments

[0042] To deeply understand the present invention, we will describe it comprehensively and meticulously. However, the present invention has various implementation manners and is not limited to the specific examples listed herein. The presentation of these examples aims to deepen the comprehensive understanding of the disclosed content of the present invention.

[0043] A closed-loop feedback system for flat-top beam uniformity optimization and centroid position control, as Figure 1As shown, the red arrow indicates the propagation direction of light, and the blue arrow indicates the connection between experimental instruments; the system includes: a laser 1, a first lens 2, a second lens 3, a first mirror 4, a second mirror 5, a third mirror 6, a spatial light modulator 7, a polarization beam splitter prism PBS 8, an achromatic lens 9, a fourth mirror 10, a camera 11, a computer 12, a high-voltage amplifier 13, a piezoelectric ceramic 14, and a λ / 2 wave plate 15;

[0044] The laser 1 generates laser light, which, after passing through the first lens 2 and the second lens 3 respectively, is reflected by the first mirror 4 into the spatial light modulator 7. Then, the spatial light modulator 7 emits the laser light to the second mirror 5, the second mirror 5 reflects the laser light to the third mirror 6, and the third mirror 6 reflects the laser light to the λ / 2 wave plate 15 to change the polarization state of the laser light. After passing through the wave plate, the laser light reaches the polarization beam splitter prism PBS 8. The laser light after passing through the polarization beam splitter prism PBS 8 is incident on the achromatic lens 9 and then emitted to the fourth mirror 10. A piezoelectric ceramic 14 is provided on the fourth mirror 10 mount to adjust the position of the light beam; the piezoelectric ceramic 14 is connected to the high-voltage amplifier 13, and the high-voltage amplifier 13 is connected to the computer 12.

[0045] Furthermore, it also includes a graphical user interface (GUI), as Figure 5 shown, to adjust multiple key parameters (such as exposure time, frame rate, gain, etc.) to optimize the working state of the camera and adapt to different experimental requirements. The graphical user interface supports real-time monitoring of the data collected by the camera, facilitating the user to adjust the intensity distribution and uniformity of the light beam to ensure that the final light beam meets the experimental requirements. This graphical user interface enhances the flexibility and operational convenience of the system; it is designed to be simple and intuitive, and the user can quickly modify the parameters by adjusting the input boxes in the interface, view the image changes in real time, and conduct debugging.

[0046] A closed-loop feedback method for optimizing the uniformity of a flat-top beam and controlling the centroid position, as Figures 2 to 3 shown, includes the following steps:

[0047] Step 1, generate an ideal target image corresponding to the target flat-top beam, input it into the Mixed Region Amplitude Freedom (MRAF) algorithm to generate the corresponding Computer-Generated Hologram (CGH) image, load the CGH image onto the spatial light modulator (SLM), and then precisely modulate the wavefront of the incident light through the spatial light modulator (SLM) to finally generate a flat-top beam on the focal plane of the lens.

[0048] Step 2, after generating a flattened beam using the MRAF algorithm and a spatial light modulator (SLM), precisely place an industrial camera at the focal plane of the lens, ensuring that the beam is incident perpendicularly at the center of the camera. This configuration guarantees that the camera can capture the accurately shaped beam image, thereby providing high-quality data for subsequent beam analysis. Use the Python programming language to control the camera. By writing control code, automate the process of image acquisition of the flattened beam, and identify and analyze the image. Adjust multiple key parameters, such as exposure time, frame rate, gain, etc., using a graphical user interface to ensure that the final beam meets the experimental requirements.

[0049] Step 3, when the flattened beam gradually stabilizes, use code control to convert the data stream captured by the camera into a bmp-format image in real time. Before identification, set an appropriate identification threshold to ensure accurate identification of the flattened beam area. The threshold should cover the entire flattened beam area and effectively avoid misidentifying low-intensity stray light as part of the beam. Set the identification area to a specific geometric shape, such as a rectangle, circle, etc., usually consistent with the geometric shape of the flattened beam. After marking the flattened beam area with a border of a certain color, calculate the coordinates of its geometric center, set this coordinate as the geometric center reference, and mark this geometric center with a specific symbol for reference;

[0050] The identification process is as Figure 4 shown (the flattened beam area is marked with a green rectangle, and the geometric center reference is represented by a blue cross symbol).

[0051] Step 4, set a distance threshold to define the maximum acceptable offset of the flattened beam. When the position offset of the beam exceeds this threshold, the system will accurately calculate the specific offset of the centroid of the flattened beam through image recognition technology and feedback this value to the computer. Determine whether the offset exceeds the distance threshold. If it does not exceed the distance threshold, continue to monitor and identify. If it exceeds the distance threshold, the computer controls the high-voltage amplifier to output a voltage signal, and the piezoelectric ceramic realizes a small displacement of the mirror frame by responding to the voltage signal, thereby accurately adjusting the direction and position of the beam and restoring the flattened beam to the predetermined position;

[0052] The output voltage V PID of the high-voltage amplifier is calculated based on the position deviation e(t) and is expressed as:

[0053] e(t) = x ref – x(t)

[0054] where e(t) is the deviation between the target centroid position x ref and the actual centroid position x(t);

[0055] The output of the high-voltage amplifier is expressed as:

[0056]

[0057] Where: K p is the proportional gain, which determines the immediate response of the high-voltage amplifier to the position deviation; K i is the integral gain, which processes the accumulated deviation; K d is the derivative gain, which processes the speed of change of the position deviation; τ is a variable time identifier used in calculating the integral from the start to the current time t, and t is the current time, which is a definite time point.

[0058] The displacement of the mirror mount is linearly related to the applied voltage, expressed as:

[0059] Δx = α·V PID (t)

[0060] Where: Δx represents the displacement of the piezoelectric ceramic; α is the displacement constant of the piezoelectric ceramic, with the unit of μm / V, representing the displacement caused by each volt of voltage; V PID (t) is the output voltage signal.

[0061] When the piezoelectric ceramic receives the voltage signal V PID (t), it will drive the mirror mount to produce a small physical displacement. This displacement precisely controls the angle and position of the mirror or other optical elements, thereby achieving precise adjustment of the light beam.

[0062] Step 5, after the position calibration is completed, perform intensity analysis on the flat-top beam image captured by the camera; divide the flat-top beam image into multiple sub-regions, calculate the average value of the pixel values in each sub-region, and further calculate the standard deviation of the average values of all sub-regions, expressed as:

[0063]

[0064] Where: σ is the standard deviation; N is the number of sub-regions; x n is the average pixel value of each sub-region; μ is the average value of all sub-region values, and the calculation formula is: This formula means that the standard deviation is the square root of the average of the squares of the deviations of all data points from the mean, reflecting the degree of dispersion of the data.

[0065] Step 6, reconstruct the target map of the flat-top beam so that the pixel values of each sub-region are adjusted according to the global average value and the uniformity deviation;

[0066] X re = X target *(ratio*0.7 + 1)

[0067] Where, X reRepresents the pixel values of each sub-region in the reconstructed target image; X target Represents the pixel values in the initial ideal target image; ratio is the difference between the average value of all sub-regions and the pixel value of a certain sub-region, divided by the average value of all sub-regions; through this formula, the system reconstructs the flat-top beam target image, enabling the pixel values of each sub-region to be adjusted according to the global average value and the uniformity deviation.

[0068] Step 7, after the reconstruction of the target image is completed, the new target image is input into the algorithm to generate a new flat-top beam; subsequently, the beam image is captured by the camera and intensity analysis is performed, and the reconstruction of the target image continues; the loop is repeated until the uniformity of the flat-top beam reaches the preset requirement, and the optimization process is terminated.

[0069] In summary, the present invention can achieve: ① High-precision beam position control: By introducing the output voltage signal of the high-voltage amplifier and piezoelectric ceramic drive, and combining with real-time image recognition, the present invention realizes high-precision control of the centroid position of the flat-top beam. The traditional method of manually adjusting the optical elements in the optical path is difficult to achieve the same accuracy and reaction speed. The system can control the offset of the centroid position of the flat-top beam within the micron range (for example, the accuracy can reach the 5-micron level), greatly improving the stability and repeatability of the flat-top beam. ② Quantitative adjustment and flexibility: Through computer control, the system can achieve quantitative adjustment of the beam position, shape, and quality. For example, the threshold of the centroid position offset can be flexibly set according to experimental needs to ensure that the intensity, uniformity, and position of the beam are always in an ideal state. At the same time, the system can adapt to flat-top beams of various shapes, such as rectangular, circular, etc., to meet the needs of different experiments. ③ Beam uniformity optimization: The system can not only achieve precise control of the beam position, but also perform real-time analysis and optimization of the intensity distribution of the beam through image processing technology. By calculating the deviation between the pixel value of each sub-region and the global average value, and iteratively reconstructing the target image, the system can effectively improve the beam uniformity and ensure that the flat-top beam maintains a stable and consistent intensity distribution throughout the experiment.

[0070] The content not described in detail in the specification of the present invention belongs to the prior art well-known to those skilled in the art. Although the illustrative specific embodiments of the present invention are described above for the understanding of those skilled in the art of the present technology, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art of the present technology, as long as various changes are within the spirit and scope of the present invention defined and determined by the appended claims, these changes are obvious, and all inventions created using the concept of the present invention are within the scope of protection.

Claims

1. A closed-loop feedback system for flat-top beam uniformity optimization and centroid position control, characterized in that: The system comprises: a laser (1), a first lens (2), a second lens (3), a first reflector (4), a second reflector (5), a third reflector (6), a spatial light modulator (7), a polarization beam splitter prism PBS (8), an achromatic lens (9), a fourth reflector (10), a camera (11), a computer (12), a high-voltage amplifier (13), a piezoelectric ceramic (14), and a λ / 2 wave plate (15); The laser (1) generates laser light, which passes through a first lens (2) and a second lens (3) respectively, and is then reflected by a first reflector (4) into a spatial light modulator (7). Then, the spatial light modulator (7) emits the laser light to a second reflector (5). The second reflector (5) reflects the laser light to a third reflector (6). The third reflector (6) reflects the laser light to a λ / 2 wave plate (15) to change the polarization state of the laser light. After passing through the wave plate, the laser light reaches a polarization beam splitter prism PBS (8). After passing through the polarization beam splitter prism PBS (8), the laser light enters an achromatic lens (9) and then emits to a fourth reflector (10). A piezoelectric ceramic (14) is provided on a frame of the fourth reflector (10) for adjusting the position of a light beam. The piezoelectric ceramic (14) is connected to a high-voltage amplifier (13), and the high-voltage amplifier (13) is connected to a computer (12).

2. A closed-loop feedback system for flat-top beam uniformity optimization and centroid position control according to claim 1, characterized in that: It also includes a graphical user interface for adjusting multiple key parameters to optimize the working state of the camera and adapt to different experimental requirements. The graphical user interface supports real-time monitoring of data collected by the camera, and is convenient for users to adjust the intensity distribution and uniformity of the light beam to ensure that the final light beam meets the experimental requirements.

3. A closed-loop feedback method for optimizing uniformity of a flat-top beam and controlling the centroid position based on the closed-loop feedback system according to any one of claims 1 to 2, characterized in that: The following steps are involved: Step 1, generate an ideal target image corresponding to the target flat-top beam, generate the corresponding CGH map using the beam shaping algorithm, load the CGH map into the spatial light modulator, and then modulate the wavefront of the incident light through the spatial light modulator to generate a flat-top beam on the focal plane of the lens; Step 2, then accurately place the camera on the focal plane of the lens to ensure that the light beam is incident vertically at the center of the camera; ensure that the camera captures the image of the precisely shaped light beam, use the Python programming language to control the camera, automatically complete the image acquisition process of the flat-top beam, and recognize and analyze the image; Step 3: When the flat-top beam gradually becomes stable, a threshold needs to be set before image recognition to ensure accurate recognition of the flat-top beam area; The recognition area is set to a specific geometric shape, which is consistent with the geometric shape of the flat-top beam; After marking the top-hat beam area with a certain color frame, calculate the coordinates of its geometric center and set the coordinates as the geometric center reference. At the same time, mark the geometric center with a specific symbol for reference; Step 4, set a distance threshold to define the maximum acceptable offset of the flat-top beam; when the position offset of the beam exceeds the threshold, the system will accurately calculate the specific offset of the center of mass of the flat-top beam through image recognition technology, and feed the value back to the computer to determine whether the offset exceeds the distance threshold; If the distance threshold is not exceeded, monitoring and identification will continue; if the distance threshold is exceeded, the computer controls the high-voltage amplifier to output a voltage signal; the piezoelectric ceramics achieve a small displacement of the frame by responding to the voltage signal, thereby accurately adjusting the direction and position of the light beam and restoring the flat-top light beam to the predetermined position; Step 5: After the position calibration is completed, the flat-top beam image captured by the camera is subjected to intensity analysis; the flat-top beam image is divided into multiple sub-regions, the average value of the pixel values ​​in each sub-region is calculated, and the standard deviation of the average values ​​of all sub-regions is further calculated, which is expressed as: Where: σ is the standard deviation; N is the number of sub-regions; x n is the average pixel value of each sub-region; μ is the average value of all sub-region values, and the calculation formula is: Step 6, reconstructing the target image of the flat-top beam so that the pixel value of each sub-area is adjusted according to the global average value and the uniformity deviation; X re =X target *(ratio*0.7+1) Among them, X re Represents the pixel value of each sub-region in the reconstructed target image; X target represents the pixel value in the initial ideal target image; ratio is the difference between the average value of all sub-regions and the pixel value of a certain sub-region, divided by the average value of all sub-regions; Step 7: After completing the reconstruction of the target image, the new target image will be input into the algorithm to generate a new flat-top beam. Subsequently, the beam image is captured by a camera and the intensity is analyzed to continue the reconstruction of the target image. The cycle is repeated until the uniformity of the flat-top beam meets the preset requirements, and the optimization process is terminated.

4. The closed-loop feedback method for optimizing uniformity of a flat-top beam and controlling the centroid position according to claim 3, characterized in that: The threshold in step 3 should be able to cover the entire flat-top beam area and effectively avoid misidentifying low-intensity stray light as part of the beam.

5. The closed-loop feedback method for optimizing uniformity of a flat-top beam and controlling the centroid position according to claim 3, characterized in that: The output voltage V of the high voltage amplifier in step 4 PID It is calculated based on the position deviation e(t) and is expressed as: e(t)=x ref –x(t) Where e(t) is the target center of mass position x ref Deviation from the actual center of mass position x(t); The output of the high voltage amplifier is expressed as: Where: K p is the proportional gain, which determines the instantaneous response of the high voltage amplifier to position deviation; K i is the integral gain, which handles the accumulated deviation; K d is the differential gain, which processes the speed of position deviation change; τ is a changing time marker used in the integral process from the beginning to the current moment t, and t is the current moment, which is a certain time point.

6. The closed-loop feedback method for optimizing uniformity of a flat-top beam and controlling the centroid position according to claim 3, characterized in that: In step 4, the piezoelectric ceramic realizes a small displacement of the mirror frame by responding to the voltage signal. The specific method is: The mirror frame displacement is linearly related to the applied voltage and is expressed as: Δx=α·V PID (t) Where: Δx represents the displacement of the piezoelectric ceramic; α is the displacement constant of the piezoelectric ceramic, in μm / V, which represents the displacement caused by each volt of voltage; V PID (t) is the voltage signal output by the amplifier.

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