A method for shaping carbon dioxide laser beams

Abstract

This invention relates to the field of laser beam shaping technology, and discloses an active testing method and system for circuit breakers, addressing the problem that existing methods struggle to improve the adaptive shaping capability of CO2 laser beams. First, a stable optical path is constructed, ensuring its stability through mechanical limiting, a thermal management module, and multi-stage optical alignment. Then, low-power calibration is performed, generating an initial drive table for the deformable mirror using a least-squares inversion algorithm to establish a flat-top beam reference. Data is collected by a wavefront sensor, and higher-order modes are reconstructed, dynamically refreshing the deformable mirror voltage. Combined with scanning galvanometer timing synchronization, closed-loop control, and anomaly handling, wavefront control and scanning motion are synchronized. Simultaneously, the deformable mirror temperature is monitored, initiating water cooling adjustment and correcting the drive table to address thermal effects. Finally, a safety system is constructed, monitoring laser power, wavefront distortion, and deformable mirror travel parameters, and periodically purging diffractive optical elements with dry gas to achieve full-process safety assurance and performance verification.

Description

Technical Field

[0001] This invention relates to the field of laser beam shaping technology, specifically a method for shaping a carbon dioxide laser beam. Background Technology

[0002] Carbon dioxide laser therapy is a medical device based on carbon dioxide laser technology with a wavelength of 10.6μm, belonging to the far-infrared band. Its core principle utilizes the strong absorption of laser light by water molecules in tissues, achieving precise cutting, vaporization, or coagulation of soft tissues through a thermal effect. This device is widely used in dermatology, surgery, otolaryngology, gynecology, and other fields. With its advantages of high operational precision, minimal intraoperative bleeding, rapid postoperative recovery, and minimal scarring, it is particularly suitable for medical scenarios requiring delicate manipulation, becoming an important non-invasive or minimally invasive treatment tool in clinical practice. However, the main unit of this type of system has low transmittance in the 10.6μm band... Insufficient power tolerance has kept the mid-infrared region in the low-power experimental stage. Some studies have attempted to indirectly compensate for energy density fluctuations during scanning by synchronously adjusting the power of electro-optic modulators or digital servo mirrors, but these methods are limited by electro-optic conversion efficiency, crystal aperture, and driving bandwidth. This makes it difficult to achieve precise closed-loop control of multimode or pulse train waveforms, and the uniformity of light output still fluctuates by more than 10% with changes in scanning angle and power. Even with the recent emergence of mid-infrared focusing schemes based on microlens arrays or adaptive fiber endfaces, the synchronous control accuracy is still limited to single focal length or divergence angle adjustment, making it impossible to achieve integrated spatial, temporal, and polarization dynamic shaping under complex operating conditions.

[0003] Therefore, existing technologies lack a method that is compact, fast-response, high-power resistant, stable in operation, and capable of multi-degree-of-freedom closed-loop control. Existing methods lack the adaptive shaping capability of CO2 laser beams, making it difficult to meet the future demands for high power, multiple modes, and continuously adjustable beam energy density and morphology. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a carbon dioxide laser beam shaping method to solve the problem that existing methods are unable to improve the adaptive shaping capability of CO2 laser beams.

[0006] (II) Technical Solution

[0007] To achieve the goal of improving the adaptive shaping capability of CO2 laser beams mentioned in the background section, the present invention provides the following technical solution:

[0008] A method for shaping a carbon dioxide laser beam includes:

[0009] S1: The beam expander, diffractive optical element, deformable mirror, sampling wedge and scanning galvanometer are sequentially and coaxially set on a stable mechanical platform to construct a stable optical path;

[0010] S2: Under low-power calibration beam conditions, the initial wavefront distortion is measured by a wavefront sensor, and the initial driving table of the deformable mirror is generated by the least squares inversion algorithm to establish the flat-top beam reference.

[0011] S3: Real-time acquisition of wavefront data and reconstruction of Zernike polynomial higher-order modes, dynamically refreshing the deformable mirror driving voltage vector;

[0012] S4: Monitor the temperature of the deformable mirror base, set the threshold for initiating water cooling regulation, and synchronously correct the focal length control vector in the drive table based on the thermal lens effect empirical model.

[0013] S5: Obtain the real-time deflection angle of the scanning galvanometer, calculate the defocusing amount caused by the change in optical path length, and preload the phase compensation amount into the deformable mirror driving voltage.

[0014] S6: Connect the laser power, wavefront distortion parameters, and deformable mirror drive stroke data to the controller, set the emergency shutdown mechanism to be triggered when the parameters exceed the limit, and periodically purge the surface of the diffractive optical element with dry gas.

[0015] Furthermore, step S2 includes:

[0016] A honeycomb platform was built in an optical room with constant temperature and humidity and laminar flow filtration. The output power of the CO2 laser was reduced to one percent of the rated power by a variable attenuator, while ensuring that the sampling timestamps of each channel were consistent.

[0017] With the galvanometer scanning turned off, only the low-power calibration beam was allowed to pass through the shaping optical path. At least a thousand frames of focal spot centroid data were acquired using a Shack-Hartmann sensor with a kHz frame rate, and then converted into high-order Zernike coefficients online.

[0018] Apply small-amplitude step bias to all the actuators of the deformable mirror in channel order. Record the corresponding Zernike vector immediately after each bias and combine them into a response matrix. Insert a short cooling delay between two drives.

[0019] The system operates at low power output for several minutes, monitoring the wavefront RMS and energy uniformity in real time. When the RMS drops below the system set value and the energy uniformity significantly improves, the baseline is considered to have been successfully established. If the RMS rebounds within a few frames, the controller immediately switches to the safety drive and shuts off the shutter.

[0020] Furthermore, step S3 includes:

[0021] The high-speed Shack-Hartmann sensor is fixed on the sampling wedge reflection branch, and the focal spot centroid matrix is ​​acquired synchronously every frame. The sensor uses high-speed CMOS readout and performs center positioning preprocessing at the hardware level, and the sampling is triggered by a unified FPGA clock.

[0022] The centroid data enters a dedicated logic array, is first mapped to the local wavefront slope, and then reconstituted into Zernike coefficients of order 13 or higher through a pre-stored orthogonal basis transformation table. The system automatically removes sub-apertures with no signal-to-noise ratio at the edges.

[0023] The latest Zernike coefficients are fed into the control core, and the voltage increment is obtained by directly looking up the corresponding row of the response matrix generated in the static calibration stage. Then, the control core performs vector accumulation with the baseline table saved in the previous frame, and writes it into the high-resolution DAC after comparing the boundary threshold.

[0024] Furthermore, including:

[0025] The wavefront residuals calculated in real time are fed into the adaptive gain module, and the changes in the residuals are observed.

[0026] The system incorporates dual security measures, and the power meter and thermal imager are configured as a cross-validation system for calibration effectiveness.

[0027] The system incorporates a fully hardware pipeline and multi-level fault tolerance, while keeping the real-time wavefront residual within the design threshold.

[0028] Furthermore, step S4 includes:

[0029] The resistance temperature sensors are evenly distributed in the center and diagonal positions of the deformable mirror base, and the sensors are bonded to the base with thermally conductive insulating adhesive.

[0030] The analog signals output by each temperature sensor are collected and digital temperature data is generated. The first temperature threshold and the second temperature threshold are pre-stored in the digital temperature data.

[0031] Generate an empirical data table of thermal lensing effect stored inside the programmable logic device, and repair the data table according to the focal length correction amount corresponding to the temperature range;

[0032] The system periodically reads digital temperature data, calls the lookup logic of the thermal lensing effect empirical data table, and writes the focal length correction obtained from the lookup logic into the corresponding entry of the focal length control vector in the deformable mirror drive lookup table.

[0033] The driving vector refresh logic is synchronized with the lookup table logic, and the updated driving lookup table is written to the deformable mirror driving circuit within the same clock domain.

[0034] Furthermore, step S5 includes:

[0035] The dual-axis galvanometers are equipped with either absolute or incremental photoelectric encoders. The encoders are rigidly coaxially mounted with the galvanometer shafts. The angle data is connected to the controller via a differential serial bus and is triggered for sampling within the unified clock domain of the device.

[0036] The controller pre-stores scanning geometry model parameters that match the scanning focusing objective lens used, and maps the galvanometer deflection angle to the change between the image plane position and the focusing position;

[0037] The controller sets up an angle and defocus lookup table, using the galvanometer composite deflection angle as the index, outputs the corresponding defocus amount in an interpolated manner, and stores it according to the monotonic sequence of scanning angles;

[0038] The controller sets up lookup tables for defocus and phase compensation, which correspond one-to-one with the focal length control modes of the deformable lens. The lookup tables are calibrated according to the controllable modes of the deformable lens, which include the principal spherical aberration and higher-order spherical aberration components related to focus.

[0039] Furthermore, including:

[0040] The controller is configured with multi-source write arbitration logic to sequentially accumulate and refresh the deformable mirror drive vector according to a preset priority order. The priority order is determined by the controller's scheduling strategy, and timestamp alignment is completed within the same clock domain.

[0041] The deformable mirror drive circuit is composed of a digital-to-analog converter and a parallel channel driver. Before the end of each sampling period, the controller writes the arbitrated drive vector into the digital-to-analog converter and generates a synchronization flag after the writing is completed.

[0042] The controller is set with thresholds for angle overshoot and phase amplitude monitoring.

[0043] The controller sets the upper limit for angular velocity and the upper limit for angular acceleration, and the upper limit value is determined based on the galvanometer servo control characteristics.

[0044] The controller sets the objective type identifier field and selects the corresponding scanning geometry model and field curvature compensation parameters based on the identifier;

[0045] The controller sets up a running log buffer and periodically outputs it to the host computer for archiving. The recording order in the buffer is consistent with the sampling trigger order.

[0046] Furthermore, step S6 includes:

[0047] Set up a high-speed analog or digital input port for connecting a thermal power laser power meter;

[0048] A data acquisition interface is provided to be compatible with the Shack-Hartmann wavefront sensor, and the interface is synchronized with the device's master clock.

[0049] Set up a stroke monitoring channel connected to the feedback bus of the deformable mirror driver to generate deformable mirror stroke parameters and compare them with safety thresholds in the controller;

[0050] A programmable logic controller is configured as the interlocking core. The controller reads the laser power, wavefront distortion parameters and deformable mirror travel sequentially according to a fixed scanning cycle, performs threshold comparison and logical OR operation, and outputs a shutdown command when the shutdown condition is met.

[0051] The interlocking circuit meets the requirements of laser product safety standards regarding environmental conditions, single-point failures, and protective interlocking.

[0052] A parameterizable confirmation timer is set inside the controller. When any monitored quantity is detected to exceed the corresponding threshold, a delayed confirmation is initiated, and a shutdown signal is output when the state is still in the over-limit state at the end of the confirmation period.

[0053] The time base of the confirmation timer is consistent with the sampling clock.

[0054] Furthermore, including:

[0055] Set clean, dry air or nitrogen as the purging medium, and configure filtration, pressure reduction, and dew point control modules;

[0056] Mass flow meters and solenoid valves are installed in the purging branch. Coriolis mass flow meters are preferred to balance response speed and measurement accuracy.

[0057] An annular or multi-point distribution nozzle is arranged circumferentially on the diffractive optical element, and a pressure switch or differential pressure switch is installed in the gas path.

[0058] A humidity sensor is installed in the optical cavity or equipment environment. The controller adjusts the purging cycle and duration within a set range based on the humidity data, and shortens the purging interval when the humidity exceeds the set threshold. The humidity data and purging events are recorded together.

[0059] Set up an operation log buffer to record laser power, wavefront distortion parameters, deformable mirror travel, interlock status, purge flow and dew point information at fixed intervals, and archive them for a long time through a host computer or database interface.

[0060] The human-machine interface is configured to display the real-time values ​​and thresholds of the three types of monitoring quantities, and provides a manual purging button and an interlock reset button.

[0061] Compared with the prior art, the present invention provides a carbon dioxide laser beam shaping method, which has the following beneficial effects:

[0062] 1. An adaptive loop is constructed by using a microelectromechanical deformable mirror (MEMS) in conjunction with a fast frame rate Shack-Hartmann wavefront sensor. The MEMS deformable mirror has microsecond-level mechanical response and kilohertz-level update capability, which is significantly higher than the refresh rate of traditional low-frequency adaptive solutions, covering the rapid aberration fluctuations caused by galvanometer scanning. The incident angle and the image plane position are approximately linearly correlated. The objective lens is designed to make the field point position proportional to the incident angle and provide an approximately flat image plane. The galvanometer angle is mapped to the defocus amount through a geometric model, and phase compensation is preset on the DM focal length-related mode. This can maintain the consistency of morphology and energy distribution during large-angle scanning, thereby improving the adaptive shaping capability of CO2 laser beam.

[0063] 2. Long-term operation of CO2 lasers can easily induce thermal lensing effect. The thermo-optic coefficient of the medium determines the equivalent focal shift caused by the change of refractive index with temperature. The thermo-optic coefficient of ZnSe is positive at 10.6μm. Temperature rise will change the effective optical path. By deploying multiple temperature sensors on the base, establishing an empirical data table of temperature-focal length correction and writing it into a lookup table, feedforward compensation of thermally induced phase can be performed at the control level to reduce the impact of thermal drift on uniformity and focal depth. Attached Figure Description

[0064] Figure 1 This is a flowchart of a carbon dioxide laser beam shaping method according to the present invention. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] Please see Figure 1 The present invention provides an active testing method for circuit breakers, comprising:

[0067] S1: The beam expander, diffractive optical element, deformable mirror, sampling wedge, and scanning galvanometer are sequentially and coaxially mounted on a stable mechanical platform to construct a stable optical path. The specific implementation is as follows:

[0068] This system is a high-precision laser transmission and shaping device, integrating optical, mechanical, control, and thermal management technologies. The optical component employs a three-element Galilean beam expander assembly to construct a 3x magnification beam expander system with an inlet aperture of 6mm and an outlet aperture of 18mm. It is coated with dual-wavelength AR films of 9.3μm or 0.6μm. Detected using a ZYGO Verifire IR interferometer, the wavefront distortion PV value at 10.6μm is better than λ / 12, where λ represents the laser operating wavelength. It meets the requirements for flat-top shaping. The ZnSe diffractometer flat-top shaper is designed with a diffraction efficiency of 95% and a damage resistance threshold ≥15kW / cm². 2 After a 30-minute ablation test with 200W continuous light, the surface showed no carbonization and the power transmission attenuation was <0.3%. The 140-channel MEMS deformable mirror was scanned channel by channel by channel using a white light interferometer 3D profilometer. The initial static flatness of the mirror surface was <12nm. The wedge-shaped sampling plate with a wedge angle of 2° and an outer diameter of 25.4mm, the reflective surface was gold-plated for enhancement, the sampling ratio was 2%, the working aperture was 20mm, the maximum scanning angle was ±20°, and the dynamic repeatability was ±20μrad. Together, the dual-axis Galvo galvanometer scanning head constituted the beam transmission end.

[0069] In terms of mechanical structure, the substrate adopts a 25mm thick 6061-T6 aluminum alloy honeycomb optical platform with a surface flatness of ±0.02mm. All adjustment seats are equipped with a six-degree-of-freedom precision adjustment frame to ensure the initial positioning accuracy of optical components. To suppress thermal drift, the DOE, DM and galvanometer are integrated into a 10mm thick Invar-36 modular sub-platform, which is limited by two 6mm stop positioning posts. The assembly and disassembly reset error is ≤10μm. The water cooling system adopts a 6mm stainless steel bellows with a quick-connect self-sealing valve. No drainage is required when replacing the DOE or DM, which takes into account both thermal management and maintenance convenience.

[0070] The optical alignment process is implemented in stages. First, a crosshair target is installed at the output end of the CO2 laser. Using an infrared tracer card and a silicon-based CCD coaxial observer, the initial laser center is positioned. The input side of the beam expander is concentrically assembled with the mechanical stop of the laser flange. The concentricity of the four-point contact is checked using a 0-25mm inner diameter dial indicator, with an error ≤0.03mm. Then, a 5mm pinhole is installed on the output side of the beam expander as the optical axis reference. The position is recorded when the intensity of the third reflected light is lowest, achieving a true optical axis straightness of <0.02mm / 300mm after beam expansion. During DOE installation, it is placed on a high-precision five-phase adjustment frame, with 100W low-power transmission and diffraction efficiency measured by an energy meter. It is then rotated until the first-order diffraction ring disappears and locked. The far-field distribution was photographed at a distance of 200mm from the DOE exit surface using a 200mm Fourier lens to verify that the flat-top spot diameter was approximately 14mm and the energy uniformity was <8%. When fine-tuning the DOE-DM spacing, the DM was fixed on an adjustable Z-axis translation stage and finely adjusted along the optical axis to a surface spacing of 50mm. The wavefront RMS was detected using a 40×40 array Shack-Hartmann sensor. The optimization was performed to minimize the wavefront RMS and ensure that the energy fluctuation in the central flat area was <5%, with the spacing deviation within ±0.2mm. The DM amplitude modulation zero-point calibration was performed with the closed loop disabled. A +0.8V bias was applied to each channel to bring the mirror curvature close to 0D. The PV value was adjusted to within λ / 10 using a wavefront analyzer to eliminate the DOE margin phase error.

[0071] Furthermore, in the 1kW pulse power incremental test, the DOE surface temperature rise was <2℃, and the DM substrate warpage was <λ / 25. Under 4 hours of continuous wave operation at 2kW, the uniformity fluctuation of the emitted beam thermal distribution was <±3%. In terms of dynamic scanning control, a 10Hz sinusoidal trajectory was loaded onto the galvanometer, and the first ten Zernike coefficients were captured using a Shack-Hartmann sensor at a 1kHz sampling rate. The FPGA controller employed recursive least squares plus feedforward compensation to ensure that the wavefront residual σ≤λ / 18. When the scanning angle reached ±18°, the flat-top uniformity was ≥88%, and when it exceeded ±20°, the LUT-Ⅱ boundary compensation table was activated. In the final performance verification, after 5 seconds of exposure on the glass target focal plane, the radial grayscale fluctuation of the beam was <±5%. The pass rate for 50 samples each of single-point scanning and 10mm / s linear scanning was 100%. The entire optical path was tested according to GB / T15498-2018 standard, and the leakage radiation was <0.25W / cm². 2 It meets the requirements for Level 4 laser protection.

[0072] S2: Under low-power calibration beam conditions, the initial wavefront distortion is measured using a wavefront sensor, and the initial driving table of the deformable mirror is generated using a least-squares inversion algorithm to establish a flat-top beam reference. The specific implementation is as follows:

[0073] The operating environment of this system must be strictly controlled at a room temperature of 22±1℃ and a relative humidity of 40%±5% to stabilize the air refractive index and avoid wavefront measurement drift. The air velocity must be below 0.1m / s, and a local laminar flow hood with a HEPA filter must be activated to reduce dust adhesion on the DOE or DM surfaces, ensuring the cleanliness of optical components and measurement stability. The main testing equipment includes a Shack-Hartmann wavefront sensor for real-time acquisition of Zernike coefficients; a power attenuator to stably attenuate a 2kW laser to 200W; an FPGA control board for DM voltage output and wavefront data processing; and a 3-12μm infrared thermal imager for monitoring device temperature rise. The above equipment works together to ensure the testing accuracy of wavefront control, power regulation, and thermal management.

[0074] The system calibration process begins with low-power beam output and wavefront measurement. First, the galvanometer scanning function is disabled, the Q-switch is switched to continuous wave mode, and the water-cooled power attenuator is activated. Using an Ophir 10kW power meter, the laser output is confirmed to be stable at 200±2W. Specifically, the power per unit area on the DM gold-plated surface under an 18mm spot size is only approximately 0.08kW / cm². 2 Far below 5kW / cm 2 The damage threshold was determined, and the Shack-Hartmann sensor could maintain a signal-to-noise ratio >60dB at this power density without the need for an additional ND filter. Subsequently, 2% of the energy reflected from the sampling wedge was introduced into the wavefront sensor, and a 1kHz continuous sampling mode was set to record 1024 frames of wavefront data. According to the ISO 10110-5 standard, a Zernike polynomial of order 13 was used for rapid decomposition, and the initial wavefront distortion σ0≈0.27λ(RMS) and PV≈1.03λ were obtained, which are consistent with the upper limit of λ / 4(PV) of the system design, confirming that further compensation is needed.

[0075] Based on this, an initial LUT for the DM is generated using the least squares inversion algorithm. First, a system response matrix is ​​established. Then, a +20V positive pulse is applied sequentially to each of the 140 execution elements of the DM. 256 frames are simultaneously sampled using a Shack-Hartmann sensor, recording the Zernike response vector corresponding to each execution element. Each vector contains 55 coefficients, collectively forming a 55×140 system matrix, denoted as A. SVD decomposition is then performed on A.

[0076] A=UΣV T

[0077] Where: U is the left singular vector matrix, Σ is the singular value diagonal matrix, V T The transpose of the right singular vector matrix; take the singular values ​​Σ k Construct a truncation matrix from the first 120 columns of >0.1Σmax. To suppress higher-order noise, the initial wavefront σ0 is then processed with a low-pass filter to generate an ideal plane with target flat-top wavefront Wtarget≈0;

[0078] The voltage vector is solved by the least squares method.

[0079]

[0080] in: Let be the right singular vector matrix at time t. U is the inverse of the diagonal singular value matrix. T Wtarget is the transpose of the left singular vector matrix, and Wtarget is the target weight vector, representing the desired wavefront phase compensation amount.

[0081] And add a second-order compensation term

[0082] Vcorr=V+αV 2

[0083] Wherein: α≈0.012V-1, determined by the Boston Micromachines piezoelectric hysteresis curve, is used to correct the nonlinear characteristics of DM. Vcorr is zero-padded and extended to 140 dimensions and quantized into a 14-bit DAC code value, which is written into the FPGA BRAM to establish "LUT-0". At the same time, the Shack-Hartmann real-time sampling data address is mapped to DDR3 to ensure that the LUT update is physically aligned with the data sampling and to avoid EMIF timing jitter. After 5 minutes of continuous operation, the wavefront RMS dropped to 0.046λ, PV=0.18λ, and the energy uniformity improved from 8% to 2%, which meets the starting conditions for subsequent kHz-level closed-loop control.

[0084] SVD decomposition uses 55×140 single-precision floating-point operations, with the FPGA-DPU taking 14ms in actual measurements and the least squares inversion matrix operation taking 3ms, for a total processing time of <20ms, meeting the requirements for rapid recalibration on the production line. The nonlinear compensation coefficient α is derived from the manufacturer's piezoelectric hysteresis curve. The selection of the cutoff threshold takes into account both the actual effective degrees of freedom of the DM and the low noise of the Shack-Hartmann sensor. After scanning within the range of 0.1-0.15Σmax, the corresponding value that minimizes the wavefront residual σ is selected. If the FPGA interrupt detects that the wavefront RMS > 0.15λ for 10 consecutive frames, the system will automatically revert to LUT-Safe mode and trigger the shutter to shut off the laser, ensuring equipment safety under abnormal operating conditions.

[0085] S3: Real-time acquisition of wavefront data and reconstruction of Zernike polynomial higher-order modes, dynamically refreshing the deformable mirror driving voltage vector, specifically implemented as follows:

[0086] The system's workflow encompasses power increment, scanning synchronization, closed-loop control, anomaly handling, and performance verification. First, power increment and thermal stabilization are performed. The laser starts at 200W during static calibration and gradually increases power in steps: 500W (30s) → 1kW (30s) → 1.5kW (30s) → 2kW (steady-state). During each power level, the temperature rise of the deformable mirror substrate and the surface temperature rise of the diffractive optical elements are monitored in real time to ensure a temperature difference ΔT < 3℃. If this limit is exceeded, power increment is paused and the stabilization time of the current power level is extended. After the power reaches a steady-state of 2kW, the system runs continuously for 3 minutes. Infrared thermal imaging confirms that the maximum warpage of the DM mirror is < λ / 30 and the DOE center temperature drift is < 1℃. Simultaneously, the water cooling system maintains a fixed flow rate of 8L / min. Finally, the power meter verifies that the system output power fluctuation is < ±1.5%, providing a stable thermal environment for subsequent closed-loop control.

[0087] Subsequently, galvanometer scanning and timing synchronization were performed. First, the galvanometer controller loaded an 8kHz sinusoidal preamble-trapezoidal main scan-cosine tail combined trajectory with a scanning angle of ±18° and a repetition frequency of 100Hz, simulating the radial uniform speed sweep of a wafer annealing process. The system used a 1MHz reference clock output from the FPGA. The galvanometer angle encoder, Shack-Hartmann focal plane array trigger, and DM digital-to-analog converter refresh were all synchronously locked to this clock. The wavefront sampling frame period Ts = 1ms, the DM voltage write delay Td = 220μs, and the galvanometer angle update delay Tg = 70μs. Timing alignment ensured the total time difference.

[0088] ΔTtotal=|Ts-Td-Tg|<0.5ms

[0089] It meets the consistency requirements of wavefront compensation and scanning angle synchronization;

[0090] Based on this, a 1kHz closed-loop wavefront control algorithm is implemented. First, the Shack-Hartmann sensor outputs 40×40 focal spot centroid coordinates, which are then processed in a three-step pipeline by the FPGA DSP core, with a total processing time ≤120μs; the system response matrix A is pre-stored in Block RAM. t and Voltage vector calculation is performed using a three-stage pipeline multiplying array.

[0091]

[0092] The computation time is 72μs at a 250MHz vectorized clock, followed by writing to the driver DM via a 14-bit DAC. The closed-loop delay consists of reconstruction, inversion, and the DAC and driver cycles, with a total τ. loop≈220μs, corresponding to a closed-loop cutoff frequency of ≈725Hz, which can cover the 100Hz fundamental wave and the first 7 harmonics of the galvanometer main scan, ensuring the timing synchronization of wavefront control and scanning motion;

[0093] To improve control stability, the system introduces a gain-adaptive PID strategy and an anomaly switching mechanism: real-time monitoring of wavefront RMS, where a threshold...

[0094] σ th =λ / 12

[0095] With the uniformity U(t) of the CCD flat-top image, where the threshold

[0096] U th =0.90

[0097] If any indicator exceeds the limit for 3 consecutive frames, the adaptive PID control mode is triggered, where the PID is controlled by σ. th Let σ be the controlled variable. ref =λ / 15, error e(t) = σ ref -σ th The gain is automatically switched according to |e(t)|, and it enters the high-gain region when |e(t)|>0.05λ, where K p =1.8, K i =12, K d =0.002, otherwise enter the low gain region, where K p =0.9, K i =6,K d =0.001; calculated per frame

[0098] ΔV pid =K p ×e(t)+K i ×∑e(t)Δt+K d ×(de / dt)

[0099] The control quantity output by the PID controller is obtained, where de is the temperature difference, dt is the time difference, and de / dt is the rate of change of error over time.

[0100] The voltage V(n) is superimposed on the least squares inversion voltage and written into DM to balance the convergence speed and overshoot risk. In the recovery time verification, under the conditions of sudden ±2° gradient perturbation of the galvanometer and local temperature rise of 3°C in the DOE, the system makes σ(t) fall back to λ / 14 and U(t) rise to 92% within 6.3ms, which meets the design requirement of error range of 5-8ms.

[0101] In terms of safety, the system constructs a triple anomaly handling and safety interlock mechanism. When σ(t) > λ / 6 for 10ms, the FPGA immediately triggers the shutter to turn off the laser, and at the same time, the DM voltage drops back to the safety LUT to prevent the piezoelectric element from running out of control and achieve over-limit protection. The dual encoder incremental differential method is used to monitor the synchronization of the left and right axes. If the difference is > 50μrad for 5ms, it is determined to be out of step, the system enters the slow stop mode and alarms, realizing the detection of galvanometer out of step. The temperature is monitored by the DS18B20 temperature probe on the substrate. When T > 45℃, the PID amplification coefficient is automatically halved and the scanning angle is limited to ≤ ±10°. When T > 50℃, the laser is directly turned off to ensure equipment safety and process stability under abnormal operating conditions.

[0102] Finally, the effectiveness of the system was demonstrated through performance verification experiments. First, a scanning angle and uniformity mapping test was conducted. The scanning angle range was 0-18°, increasing by 2° increments, with each angle held for 5 seconds. The fitted average uniformity was >91.6%, and the fluctuation range was <±2%, meeting the mapping relationship requirements between scanning angle and beam uniformity. Then, a long-term stability test was conducted. The maximum drift of wavefront RMSσ(t) was only 0.006λ, and the minimum uniformity was 88.7%, which is still higher than the lower limit standard of the process. Finally, a high-frequency interference simulation was conducted. 1kHz, 2Vpp power supply noise was injected into the DM drive line, and the system maintained σ<λ / 11, verifying the strong robustness of the closed-loop control against external electromagnetic disturbances.

[0103] S4: Monitor the temperature of the deformable mirror base, set the threshold for initiating water cooling regulation, and synchronously correct the focal length control vector in the drive table based on the empirical model of the thermal lens effect. Specifically, the implementation is as follows:

[0104] With deformable mirror thermal management as the core, three high-precision Pt1000 platinum resistance thermometers are deployed to capture local thermal gradients in real time. The cooling unit adopts a microchannel copper base optimized by ANSYS CFD and conducts absorbed heat through PID closed loop. Flow monitoring uses a Coriolis mass flow meter to achieve precise water volume adjustment. Power feedback is calculated by transmissive ZnSe sheet and InGaAs detector to estimate absorbed power. The control core is a Kintex-7200T FPGA subsystem. All operations are locked to a 1MHz system clock to ensure timing synchronization.

[0105] Temperature data is sampled at 2 kS / s using a 24-bit ΣΔADC and then low-pass filtered by an IIR filter to calculate the mean T. DM (t) and gradient ΔT grad (t), diagnosing local "hot spots"; combining laser output and transmission power, calculating absorption power through a physical model to provide input for thermal control, thermally induced phase change. Based on empirical model k T=0.12rad / ℃, and allocated to the spherical aberration and second-order spherical aberration components. The 140-channel voltage adjustment is obtained by inverse solution of the response matrix, and updated after being superimposed with the current voltage. The whole process is completed on the ARM side in single-precision floating point, taking <70μs.

[0106] When T DM >35℃ and ΔT grad At <2℃, the pump speed linearly increases to 8L / min, and synchronous writing occurs. And start "Thermal-PID", if ΔT grad ≥2℃, the audible and visual shutter power is reduced by 50% and an alarm is triggered. The flow rate and temperature rise closed loop are targeted at 32℃, and the pump speed is adjusted via 50Hz PID control. The temperature is brought back within 2-3 seconds. DM Laser is shut off and cooled at full speed when the temperature is >45℃; laser is interrupted if the flow rate is <3L / min for 10ms; ΔT grad The DM voltage returns to zero at temperatures above 4℃. Forced recalibration is performed when the cumulative value exceeds 2 rad to prevent drift accumulation;

[0107] Cooling is cut off for 5 seconds under 2kW operating conditions, T DM After rising to 36.8℃, it recovered to 32.5℃ in 0.8 seconds; the light spot uniformity dropped from a minimum of 87% to 92%; 12 hours of long-term operation. The mean was 0.024 rad and the standard deviation was 0.006 rad. The temperature remained stable at 33℃-34℃ during ±20° and 150Hz scanning, with a uniformity of ≥90.8%, verifying the system's stable control capability under sudden over-temperature, long-term operation, and high dynamic load conditions.

[0108] S5: Obtain the real-time deflection angle of the scanning galvanometer, calculate the defocusing amount caused by the change in optical path length, and preload the phase compensation amount into the deformable mirror driving voltage. A specific implementation example is as follows:

[0109] At the hardware level, each of the dual-axis galvanometers is equipped with a 16-bit photoelectric encoder. Angle data (θL, θR) is sampled and de-jittered within the first 0.1ms of every 1ms time slot via the LVDS bus, ensuring timely dynamic response. At the factory, the optical path length L from the galvanometer center to the workpiece focal plane is measured using a target and stored in the FPGA's EEPROM, providing a reference for subsequent control. To address phase compensation requirements, defocusing amount Δf and DM phase increment covering 0-25° are pre-generated. Two linear interpolation lookup tables (LUTs) with Δf The data is stored in the FPGA's BRAM using a page-based cache, achieving a lookup time of <10μs and supporting fast phase compensation. Based on precise timing control, the dual-axis angles are synchronously sampled and the average value θ is calculated at T0 = 0μs. If the difference is >25μrad, an "axis deviation" event is triggered. Subsequently, at T0+20μs and T0+40μs, the linear interpolation lookup table is consulted to obtain Δf and Δt, respectively. T0+60μs will Write the compensation amount into the temporary register in a ratio of 70% spherical aberration channel and 30% secondary spherical aberration channel. Accumulate the compensation amount to the current DM voltage vector and write it into the DAC at T0+90μs. Finally, broadcast the "compensation complete" flag at T0+340μs. During the process, the galvanometer needs to maintain a forward angle of more than 0.16ms to achieve a DM galvanometer wavefront synchronization time of <0.5ms.

[0110] To ensure control stability and equipment safety, the system has established a hierarchical safety mechanism, including angular velocity protection when the rate of change of θ is >1500 deg / s. 2 Pause feedforward and retain only closed-loop control; phase and amplitude protection is checked every frame. If the absolute value exceeds the limit, the scanning angle will be reduced by 50% and a "phase overflow" message will be displayed. Synchronization monitoring compares the DM completion flag with the galvanometer timestamp. If the difference is greater than 0.8ms and there are 3 consecutive abnormal frames, resynchronization will be triggered. After 3 failures, the laser will be turned off.

[0111] In terms of status observation, the linear CCD records the grayscale of the scanned lines and calculates the uniformity in real time on the workpiece plane. When the uniformity is less than 90% and fails to meet the standard for 5 consecutive frames, the parameter self-check is triggered, and the LUT accuracy is verified by scanning angle by angle. At the same time, all key data are packaged into 1kHz log frames and support operation and maintenance traceability.

[0112] The debugging and verification results show that the uniformity is ≥93% in static angle verification; the uniformity is at least 92.1% in dynamic scanning verification, with a focus drift of <±10μm. In the error tolerance assessment, even... Introducing ±10% random deviation, the closed-loop control can still maintain uniformity ≥90%, verifying the fault tolerance capability of the feedforward and closed-loop dual-layer structure.

[0113] S6: Input the laser power, wavefront distortion parameters, and deformable mirror drive stroke data into the controller, set an emergency shutdown mechanism to be triggered when parameters exceed limits, and periodically purge the surface of the diffractive optical element with dry gas. Specifically:

[0114] This system constructs a complete safety system around the entire laser processing process, encompassing hardware monitoring, logic control, environmental protection, and anomaly handling. It also enables long-term traceability and analysis through data archiving. At the hardware configuration level, dedicated monitoring channels are designed for key parameters such as laser power, wavefront quality, and actuator status. Laser power is measured using an InGaAs power meter installed 200mm from the laser exit point behind a 4% reflection sampling plate, capturing power fluctuations in real time at a rate of 10kS / s. Wavefront RMS is monitored using a 40×40 sub-aperture Shack-Hartmann wavefront instrument in the 2% reflection optical path of the sampling wedge, with a rate of 1kS / s ensuring beam shaping quality. DM travel relies on a BOS-DM140 driver with a built-in 14-bit displacement sensor to detect the piezoelectric ceramic status. The PLC master station executes interlocking logic in a 1ms cycle scan, and a 24V optical isolation relay is configured on the Q-Switch shutdown line to ensure emergency laser shutdown.

[0115] The interlocking logic achieves multi-parameter coordinated protection through ladder diagrams. First, the power upper limit is set to 2.3kW, the lower limit to 1.6kW, the upper limit of wavefront RMS is λ / 10, and the upper limit of DM stroke is 90% of full scale. Then, the PLC reads and compares the data from the three channels every 1ms. If any parameter exceeds the limit, the corresponding alarm bit is set, and a comprehensive alarm signal ALM is formed through OR logic. After ALM is triggered, a 10ms delay timer is started. If the fault is not eliminated, the Q-Switch is shut down, the safety lock is set, and a message is sent.

[0116] After the operator clears the fault and resets the alarm, the HMI will only light up the enable button if three conditions are met simultaneously: three parameters return to the safe zone, DM stroke < 70% of full scale, and wavefront RMS continuously < λ / 12 for 3 seconds.

[0117] To ensure the dryness of DOE optical components, an oil-free air compressor and a refrigerated dryer are configured as the air source. The flow rate is controlled by a mass flow meter and an FKM sealed solenoid valve. The annular micro-orifice nozzle evenly covers the substrate. The PLC automatically performs a 60-second purging every 8 hours. When the ambient humidity is >60%, the cycle is shortened to 4 hours and an alert is issued. Manual immediate purging can bypass the timer, and the 8-hour cycle is automatically reloaded after the operation. The PLC sends power, wavefront, stroke, and event codes to InfluxDB at 10ms intervals. Each purging record records the timestamp, flow rate, duration, and RH in the DOE_PURGE table. A daily safety operation report is generated at 00:00 every day, which includes the runtime, ALM trigger statistics, the last purging time, parameter extreme values ​​and average values, providing full-process traceability and long-term data support for operation and maintenance analysis.

[0118] This embodiment first constructs a stable optical path by coaxially mounting the beam expander, diffractive optical elements, deformable mirror, sampling wedge, and scanning galvanometer on a stable mechanical platform. Mechanical limiting, a thermal management module, and multi-stage optical alignment, including initial positioning, optical axis straightness calibration, and diffraction efficiency verification, ensure the stability of the optical path. Subsequently, low-power calibration is performed, measuring the initial wavefront distortion under low-power beam conditions. An initial driving table for the deformable mirror is generated using a least-squares inversion algorithm, establishing a flat-top beam reference. In the real-time control phase, data is collected by the wavefront sensor and higher-order modes are reconstructed, dynamically refreshing the deformable mirror voltage. Combined with scanning galvanometer timing synchronization, closed-loop control, and anomaly handling, wavefront control and scanning motion are synchronized. Simultaneously, the deformable mirror temperature is monitored, water cooling is initiated, and the driving table is corrected to address thermal effects. The defocusing amount is calculated based on the real-time galvanometer angle, and phase compensation is pre-loaded onto the deformable mirror. Finally, a safety system is constructed, monitoring key parameters such as laser power, wavefront distortion, and deformable mirror travel. An emergency shutdown is triggered when limits are exceeded, and the diffractive optical elements are periodically purged with dry gas, achieving full-process safety assurance and performance verification.

[0119] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wireless or wired transmission; wired transmission methods include optical fiber, twisted pair, coaxial cable, etc.; wireless transmission includes infrared, microwave, etc. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center containing one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0120] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0122] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0123] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0124] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0125] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0126] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for shaping a carbon dioxide laser beam, characterized in that, Includes the following steps: S1: The beam expander, diffractive optical element, deformable mirror, sampling wedge and scanning galvanometer are sequentially and coaxially set on a stable mechanical platform to construct a stable optical path; S2: Under low-power calibration beam conditions, the initial wavefront distortion is measured by a wavefront sensor, and the initial driving table of the deformable mirror is generated by the least squares inversion algorithm to establish the flat-top beam reference. S3: Real-time acquisition of wavefront data and reconstruction of Zernike polynomial higher-order modes, dynamically refreshing the deformable mirror driving voltage vector; S4: Monitor the temperature of the deformable mirror base, set the threshold for initiating water cooling regulation, and synchronously correct the focal length control vector in the drive table based on the thermal lens effect empirical model. S5: Obtain the real-time deflection angle of the scanning galvanometer, calculate the defocusing amount caused by the change in optical path length, and preload the phase compensation amount into the deformable mirror driving voltage. S6: Connect the laser power, wavefront distortion parameters, and deformable mirror drive stroke data to the controller, set the emergency shutdown mechanism to be triggered when the parameters exceed the limit, and periodically purge the surface of the diffractive optical element with dry gas.

2. The carbon dioxide laser beam shaping method according to claim 1, characterized in that, Step S2 includes: A honeycomb platform was built in an optical room with constant temperature and humidity and laminar flow filtration. The output power of the CO2 laser was reduced to one percent of the rated power by a variable attenuator, while ensuring that the sampling timestamps of each channel were consistent. With the galvanometer scanning turned off, only the low-power calibration beam was allowed to pass through the shaping optical path. At least a thousand frames of focal spot centroid data were acquired using a Shack-Hartmann sensor with a kHz frame rate, and then converted into high-order Zernike coefficients online. Apply small-amplitude step bias to all the actuators of the deformable mirror in channel order. Record the corresponding Zernike vector immediately after each bias and combine them into a response matrix. Insert a short cooling delay between two drives. The system operates at low power output for several minutes, monitoring the wavefront RMS and energy uniformity in real time. When the RMS drops below the system set value and the energy uniformity significantly improves, the baseline is considered to have been successfully established. If the RMS rebounds within a few frames, the controller immediately switches to the safety drive and shuts off the shutter.

3. The carbon dioxide laser beam shaping method according to claim 1, characterized in that, Step S3 includes: The high-speed Shack-Hartmann sensor is fixed on the sampling wedge reflection branch, and the focal spot centroid matrix is ​​acquired synchronously every frame. The sensor uses high-speed CMOS readout and performs center positioning preprocessing at the hardware level, and the sampling is triggered by a unified FPGA clock. The centroid data enters a dedicated logic array, is first mapped to the local wavefront slope, and then reconstituted into Zernike coefficients of order 13 or higher through a pre-stored orthogonal basis transformation table. The system automatically removes sub-apertures with no signal-to-noise ratio at the edges. The latest Zernike coefficients are fed into the control core, and the voltage increment is obtained by directly looking up the corresponding row of the response matrix generated in the static calibration stage. Then, the control core performs vector accumulation with the baseline table saved in the previous frame, and writes it into the high-resolution DAC after comparing the boundary threshold.

4. The carbon dioxide laser beam shaping method according to claim 3, characterized in that, include: The wavefront residuals calculated in real time are fed into the adaptive gain module, and the changes in the residuals are observed. The system incorporates dual security measures, and the power meter and thermal imager are configured as a cross-validation system for calibration effectiveness. The system incorporates a fully hardware pipeline and multi-level fault tolerance, while keeping the real-time wavefront residual within the design threshold.

5. The method for shaping a carbon dioxide laser beam according to claim 1, characterized in that, Step S4 includes: The resistance temperature sensors are evenly distributed in the center and diagonal positions of the deformable mirror base, and the sensors are bonded to the base with thermally conductive insulating adhesive. The system collects analog signals output from each temperature sensor and generates digital temperature data, and pre-stores the first and second temperature thresholds within the digital temperature data. Generate an empirical data table of thermal lensing effect stored inside the programmable logic device, and repair the data table according to the focal length correction amount corresponding to the temperature range; The system periodically reads digital temperature data, calls the lookup logic of the thermal lensing effect empirical data table, and writes the focal length correction obtained from the lookup logic into the corresponding entry of the focal length control vector in the deformable mirror drive lookup table. The driving vector refresh logic is synchronized with the lookup table logic, and the updated driving lookup table is written to the deformable mirror driving circuit within the same clock domain.

6. The carbon dioxide laser beam shaping method according to claim 1, characterized in that, Step S5 includes: The dual-axis galvanometers are equipped with either absolute or incremental photoelectric encoders. The encoders are rigidly coaxially mounted with the galvanometer shafts. The angle data is connected to the controller via a differential serial bus and is triggered for sampling within the unified clock domain of the device. The controller pre-stores scanning geometry model parameters that match the scanning focusing objective lens used, and maps the galvanometer deflection angle to the change between the image plane position and the focusing position; The controller sets up an angle and defocus lookup table, using the galvanometer composite deflection angle as the index, outputs the corresponding defocus amount in an interpolated manner, and stores it according to the monotonic sequence of scanning angles; The controller sets up lookup tables for defocus and phase compensation, which correspond one-to-one with the focal length control modes of the deformable lens. The lookup tables are calibrated according to the controllable modes of the deformable lens, which include the principal spherical aberration and higher-order spherical aberration components related to focus.

7. The carbon dioxide laser beam shaping method according to claim 6, characterized in that, include: The controller is configured with multi-source write arbitration logic to sequentially accumulate and refresh the deformable mirror drive vector according to a preset priority order. The priority order is determined by the controller's scheduling strategy, and timestamp alignment is completed within the same clock domain. The deformable mirror drive circuit is composed of a digital-to-analog converter and a parallel channel driver. Before the end of each sampling period, the controller writes the arbitrated drive vector into the digital-to-analog converter and generates a synchronization flag after the writing is completed. The controller is set with thresholds for angle overshoot and phase amplitude monitoring. The controller sets the upper limit for angular velocity and the upper limit for angular acceleration, and the upper limit value is determined based on the galvanometer servo control characteristics. The controller sets the objective type identifier field and selects the corresponding scanning geometry model and field curvature compensation parameters based on the identifier; The controller sets up a running log buffer and periodically outputs it to the host computer for archiving. The recording order in the buffer is consistent with the sampling trigger order.

8. The method for shaping a carbon dioxide laser beam according to claim 1, characterized in that, Step S6 includes: Set up a high-speed analog or digital input port for connecting a thermal power laser power meter; A data acquisition interface is provided to be compatible with the Shack-Hartmann wavefront sensor, and the interface is synchronized with the device's master clock. Set up a stroke monitoring channel connected to the feedback bus of the deformable mirror driver to generate deformable mirror stroke parameters and compare them with safety thresholds in the controller; A programmable logic controller is configured as the interlocking core. The controller reads the laser power, wavefront distortion parameters and deformable mirror travel sequentially according to a fixed scanning cycle, performs threshold comparison and logical OR operation, and outputs a shutdown command when the shutdown condition is met. The interlocking circuit meets the requirements of laser product safety standards regarding environmental conditions, single-point failures, and protective interlocking. A parameterizable confirmation timer is set inside the controller. When any monitored quantity is detected to exceed the corresponding threshold, a delayed confirmation is initiated, and a shutdown signal is output when the state is still in the over-limit state at the end of the confirmation period. The time base of the confirmation timer is consistent with the sampling clock.

9. A method for shaping a carbon dioxide laser beam according to claim 8, characterized in that, include: Set clean, dry air or nitrogen as the purging medium, and configure filtration, pressure reduction, and dew point control modules; Mass flow meters and solenoid valves are installed in the purging branch to balance response speed and measurement accuracy. An annular or multi-point distribution nozzle is arranged circumferentially on the diffractive optical element, and a pressure switch or differential pressure switch is installed in the gas path. A humidity sensor is installed in the optical cavity or equipment environment. The controller adjusts the purging cycle and duration within a set range based on the humidity data, and shortens the purging interval when the humidity exceeds the set threshold. The humidity data and purging events are recorded together. Set up an operation log buffer to record laser power, wavefront distortion parameters, deformable mirror travel, interlock status, purge flow and dew point information at fixed intervals, and archive them for a long time through a host computer or database interface. The human-machine interface is configured to display the real-time values ​​and thresholds of the three types of monitoring quantities, and provides a manual purging button and an interlock reset button.

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