A three-path parallel ultrafast laser shaping system and method based on space-time compensation

Abstract

This invention belongs to the field of laser shaping technology and provides a three-channel parallel ultrafast laser shaping system and method based on spatiotemporal compensation. By setting a pre-dispersion compensation module, this invention introduces controlled negative dispersion in advance, thereby precisely offsetting the pulse broadening induced by digital micromirror array diffraction and thick glass elements in subsequent branches, ensuring that the pulse width of each shaping branch at the focal plane remains in a fidelity state. The beam is distributed to three functionally complementary shaping branches, and a digital virtual focal length is generated by superimposing a specific quadratic phase function. This allows for dynamic compensation of focal position deviations between branches without moving any mechanical components, achieving instantaneous drift-free alignment of multimodal coaxial focal points. This invention not only achieves multi-dimensional flexible customization of the processed morphology but also ensures high consistency of processing thresholds and high fidelity of spatiotemporal pulses during high-speed switching of modes.

Description

Technical Field

[0001] This invention belongs to the field of laser shaping technology, specifically relating to a three-channel parallel ultrafast laser shaping system and method based on spatiotemporal compensation. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] In the field of ultrafast laser precision machining, laser shaping solutions typically employ spatial light modulators or diffractive optical elements. Due to the wide spectral bandwidth of ultrafast lasers, the crystals and lenses used in the shaping process will produce varying degrees of dispersion. This dispersion will cause pulse distortion or broadening, resulting in a significant drop in peak power and severely affecting processing accuracy and heat-affected zone control.

[0004] Meanwhile, in industrial integration scenarios, a single shaping method is difficult to balance processing efficiency and precision requirements. If switching between different forms (such as line laser, Bessel light and irregular light) is required, the difference in diffraction characteristics of different components will cause a significant drift in their physical focal plane. Traditional mechanical compensation methods are not only slow to respond, but also have backlash errors, making it difficult to achieve high-precision instantaneous alignment. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a three-channel parallel ultrafast laser shaping system and method based on spatiotemporal compensation. This invention achieves multi-dimensional flexible customization of the processed morphology, ensuring high consistency of processing thresholds and high fidelity of spatiotemporal pulses during high-speed switching of various modes.

[0006] According to some embodiments, the present invention adopts the following technical solution: A three-way parallel ultrafast laser shaping system based on spatiotemporal compensation includes a pre-dispersion compensation device, a beam shaping device, and a beam quality feedback device. The pre-dispersion compensation device is connected to the laser and is used to provide negative group velocity dispersion to the laser pulse of the laser to counteract the pulse broadening generated by the subsequent device. The beam shaping device includes three parallel branches and a beam combining module, and uses an optical switch to control the branch into which the laser pulse processed by the pre-dispersion compensation device enters. The first branch is used to transmit the laser pulse as a line beam and focus it on the surface of the object being processed, propagating it as a Bessel beam to achieve deep focal depth cutting. The second branch is used to emit laser pulses in the form of quasi-parallel light and change the shape of the light pulses, shaping the Gaussian beam into a vortex beam or a Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with large focal depth. The third branch is used to emit laser pulses in the form of quasi-parallel light, and to shape the quasi-parallel Gaussian light into flat light, and the flat-top light into irregular light spots; The beams from each branch are reflected to the beam combining module, which controls the beam polarization to achieve beam combining and output a unified beam. The beam quality feedback device is used to split the combined laser pulses according to a predetermined splitting ratio. One beam is used for laser processing, and the other beam is used to monitor the pulse shape and width. Based on the monitoring results, the negative group velocity dispersion of the pre-dispersion compensation device is dynamically adjusted so that the laser pulse is always close to the transform limit width.

[0007] As an alternative implementation, the pre-dispersion compensation device is connected to the laser via a polarization-maintaining fiber.

[0008] As an alternative implementation, the pre-dispersion compensation device includes an optical fiber collimator, a hollow roof prism, a transmission diffraction grating, and an ultrafast mirror. The spacing between the transmission diffraction gratings is adjustable. By adjusting the relative distance between them, the negative group velocity dispersion provided by the pre-dispersion compensation device is adjusted. The optical fiber collimator is used to collimate the spatial optical path and couple the spatial light back to the polarization-maintaining fiber.

[0009] As a further defined embodiment, the transmission diffraction grating is a fixed grating, which is fixed on a movable mechanism and is a movable grating.

[0010] As an alternative implementation, the first branch includes a first fiber collimator, a first cylindrical mirror, a second cylindrical mirror, and a first conical lens. The first fiber collimator is used to emit the laser pulse in the optical switch in the form of quasi-parallel light. After passing through the first cylindrical mirror, the quasi-parallel light is focused in the vertical direction to form a line beam. Then, after passing through the second cylindrical mirror, the line beam is re-collimated in the vertical direction, so that the beam can be continuously transmitted in the form of a line beam. The first conical lens propagates the shaped line beam in the form of a Bessel beam to achieve large depth of focus cutting.

[0011] As an alternative implementation, the second branch includes a second fiber collimator, a vortex waveplate, a second conical lens, a movable mechanism, and a plano-convex lens. The second fiber collimator is used to emit the laser pulse in the optical switch in the form of quasi-parallel light. The vortex waveplate and the second conical lens are fixed on the movable mechanism. By controlling the movable mechanism, the vortex waveplate or the second conical lens can change the shape of the light pulse, shaping the Gaussian beam into a vortex beam or a circular Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for large depth-of-focus drilling. The plano-convex lens is used to focus the vortex beam or the circular Bessel beam so that the focal point of the second branch is located on the same Z-axis plane as the linear light spot in the first branch.

[0012] As a further specified embodiment, the movable mechanism is an electric displacement stage.

[0013] As an optional implementation, the third branch includes a third fiber collimator, a first compound eye lens, a second compound eye lens, a first ultrafast reflector, a second ultrafast reflector, a digital micromirror array, and a dichroic mirror. The third fiber collimator is used to emit the laser pulse in the optical switch in the form of quasi-parallel light. The compound eye lens group composed of the first and second compound eye lenses shapes the quasi-parallel Gaussian light into flat light. The shaped flat light is reflected by the first ultrafast reflector to the surface of the digital micromirror array. Under the control of the host computer, the flat-top light is shaped into an irregular light spot, and the shaped beam is reflected by the second ultrafast reflector to the beam combining module, which outputs the beam uniformly.

[0014] As an alternative implementation, the beam combining module includes a third ultrafast mirror, a first half-wave plate, a second half-wave plate, a third half-wave plate, a first polarizing beam splitter, and a second polarizing beam splitter. The third ultrafast mirror is located at the end of the first branch, the first half-wave plate is located between the third ultrafast mirror and the first polarizing beam splitter, the third half-wave plate is located at the end of the third branch, the second polarizing beam splitter is located at the rear end of the third half-wave plate, and the second half-wave plate is located between the first polarizing beam splitter and the second polarizing beam splitter. The three half-wave plates are mounted on a rotatable mechanism. By controlling their fast axis angle, the beam polarization is controlled to achieve the beam combining function, so that all three branches output from the same outlet.

[0015] As a further defined embodiment, the rotatable mechanism is an electrically operated rotary platform.

[0016] As an alternative implementation, the beam quality feedback device includes a beam splitter, a processing platform, an illumination device, an autocorrelator, an industrial camera, and a host computer. The beam splitter is an unrelated polarization beam splitter, with one end transmitting and being focused on the processing platform to achieve laser processing. The reflected laser pulse is calibrated and then enters the autocorrelator. The host computer monitors the pulse shape and width and dynamically adjusts the relative distance between the transmission diffraction grating and the transmission diffraction grating based on the monitoring results, so that the laser pulse is always close to the transformation limit width.

[0017] As a further defined embodiment, the processing platform is an electrically driven six-axis displacement stage.

[0018] The working method of the above system includes the following steps: A pre-dispersion compensation device is used to provide negative group velocity dispersion to the laser pulse of the laser to counteract the pulse broadening generated by subsequent devices; The branch into which the laser pulse processed by the pre-dispersion compensation device enters is controlled by an optical switch; The first branch transmits the laser pulse as a line beam and focuses it on the surface of the object being processed, propagating it as a Bessel beam to achieve deep focal depth cutting. The second branch emits the laser pulse in the form of quasi-parallel light and changes the shape of the light pulse, shaping the Gaussian beam into a vortex beam or a Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with large focal depth. The third branch emits the laser pulse in the form of quasi-parallel light, and shapes the quasi-parallel Gaussian light into flat light, and shapes the flat-top light into irregular light spots; The beams from each branch are reflected to the beam combining module, which controls the beam polarization to achieve beam combining and output a unified beam. The beam quality feedback device splits the combined laser pulses into beams according to a predetermined splitting ratio. One beam is used for laser processing, and the other beam is used to monitor the pulse shape and width. Based on the monitoring results, the negative group velocity dispersion of the pre-dispersion compensation device is dynamically adjusted so that the laser pulse is always close to the transform limit width.

[0019] As an alternative implementation, during operation, the focal position of the beam spot output from the third branch of the beam shaping device is kept in the same Z-axis plane as the first and second branches.

[0020] As a further defining process, the third branch of the digital micromirror array introduces a quadratic phase function on the basis of the shaping function to form a virtual focal length. The virtual focal length is then linearly superimposed with the light spot shape modulation to obtain the final phase loaded on the digital micromirror array.

[0021] As a further defined implementation method, virtual focal length Its phase distribution It should meet the following requirements:

[0022] in, This represents the coordinates of each micromirror on the micromirror array; Indicates the center wavelength of the laser. This indicates the virtual focal length that needs to be generated.

[0023] As a further defining process, the final phase for:

[0024] in, To shape the phase of the light spot; For virtual lens phase, The carrier phase is used to spatially separate the +1 order signal light from the 0 order stray light.

[0025] As a further defining process, the focal length of the third branch... Virtual focal length of digital micromirror array and the physical focal length of the collimating lens Joint decision, namely:

[0026] To fix the focal length, adjust To achieve focal length movement along the Z-axis, focus offset and The relationship is represented as:

[0027] Focus offset of different spot patterns Through actual measurement, it was found that at this time: .

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention introduces a controlled negative dispersion by setting an integrated pre-dispersion compensation module at the front end of the main path. This precisely cancels out the pulse broadening induced by the diffraction of the digital micromirror array (DMD) and the thick glass element in the subsequent branches, ensuring that the pulse width at the focal plane of each shaping branch is always in a fidelity state. This allows the laser pulse to output a near-transform-limited pulse regardless of which branch it is on. It also has high scalability, allowing other devices to be introduced into the three branches to achieve additional spot shaping while ensuring the quality of the laser pulse.

[0029] This invention distributes the light beam to three complementary shaping branches via an optical switch. The first and second branches respectively use high-efficiency physical elements to generate standard line laser and special phase beam, ensuring the stability of high-power processing.

[0030] The third branch of this invention introduces a reflective DMD to achieve digital irregular shape shaping. Utilizing the programmable phase characteristics of the DMD in the third branch, a digital virtual focal length is generated by superimposing a quadratic phase function. This allows for dynamic compensation of focal position deviations between branches without moving any mechanical components, achieving instantaneous drift-free alignment of multi-modal coaxial focal points. Through digital virtual focal length compensation, the problem of focal position inconsistency between physical branches (line laser, Bessel beam) and digital shaping branches is solved. This achieves "zero mechanical movement" during mode switching, ensuring high overlap of the focal planes of different modal beams in multi-process integrated machining.

[0031] This invention not only achieves multi-dimensional flexible customization of the processing morphology, but also ensures the high consistency of processing thresholds and the high fidelity of spatiotemporal pulses during high-speed switching of various modes.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0034] Figure 1 This is a schematic diagram of the overall optical path device according to one embodiment. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] Where there is no conflict, the embodiments and features described in this application may be combined with each other.

[0039] Example 1 A spatiotemporally compensated three-channel parallel ultrafast laser shaping system, such as Figure 1 As shown, it includes a pre-dispersion compensation device, a beam shaping device, and a beam quality feedback device, wherein: The pre-dispersion compensation device is connected to the ultrafast laser via a polarization-maintaining fiber and consists of a fiber collimator (A01), a fiber collimator (A06), a hollow roof prism (A05), a transmission diffraction grating (A03), a transmission diffraction grating (A04), and an ultrafast mirror (A02).

[0040] In this embodiment, the transmission diffraction grating (A03) is a fixed grating, and the transmission diffraction grating (A04) is fixed on the electric displacement stage and is a movable grating. By changing the relative distance between the transmission diffraction grating (A04) and the transmission diffraction grating (A03), the negative group velocity dispersion (GDD) provided by the pre-dispersion compensation device is adjusted to counteract the pulse broadening caused by the diffraction of the thick glass element and DMD in the subsequent optical path, so that the beam maintains a pure near-transform-limit pulse after the beam is shaped in different branches; the fiber collimator (A06) is used to collimate the spatial optical path and couple the spatial light back to the polarization-maintaining fiber.

[0041] Of course, in this embodiment, the ultrafast laser can be a femtosecond laser.

[0042] However, in other embodiments, the ultrafast laser can also be a picosecond or attosecond ultrashort pulse laser.

[0043] In some embodiments, the electric displacement stage can be replaced with a mechanical displacement device, as long as the position can be moved.

[0044] Alternatively, both the transmission diffraction grating (A03) and the transmission diffraction grating (A04) can be set on different displacement devices, as long as the distance between them is adjustable.

[0045] The beam shaping device consists of branch I, branch II, branch III and a beam combining module. Branch I, branch II and branch III are respectively connected to a polarization-maintaining fiber optic switch (B01). The optical switch (B01) is used to control which branch the femtosecond pulse enters.

[0046] In other embodiments, the optical switch can be an electro-optical optical switch, a mechanical optical switch, a liquid crystal optical switch, etc. The optical switch can be 1×3, 1×N, or a matrix type, and the specific choice depends on the circumstances. No exhaustive list is provided here.

[0047] Branch I consists of an optical fiber collimator (B02), a cylindrical mirror (B05), a cylindrical mirror (B06), and a conical lens (B08). The optical fiber collimator (B02) emits the laser pulse from the optical switch (B01) as quasi-parallel light. After passing through the cylindrical mirror (B05), the quasi-parallel light is focused vertically to form a line beam. Then, after passing through the cylindrical mirror (B06), the line beam is re-collimated vertically, enabling the beam to be continuously transmitted as a line beam and focused on the surface of the object being processed. The conical lens (B08) propagates the shaped line beam as a Bessel beam to achieve large depth of focus cutting.

[0048] The beam shaping device branch II consists of an optical fiber collimator (B03), a vortex waveplate (B12), a conical lens (B11), an electric displacement stage (B10), and a plano-convex lens (B13). The optical fiber collimator (B03) is used to emit the laser pulse from the optical switch (B01) in the form of quasi-parallel light. The vortex waveplate (B12) and the conical lens (B11) are fixed on the electric displacement stage (B10) by a lens frame. By controlling the electric displacement stage (B10), the vortex waveplate (B12) or the conical lens (B11) can change the shape of the light pulse, shaping the Gaussian beam into a vortex beam or a circular Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with a large focal depth. The plano-convex lens (B13) is used to focus the vortex beam or the circular Bessel beam so that the focal point of this branch II is located on the same Z-axis plane as the linear spot of branch I.

[0049] Of course, in some embodiments, the electric displacement stage can be replaced with a mechanical displacement device, as long as the position can be moved.

[0050] The beam shaping device branch III consists of an optical fiber collimator (B04), a compound eye lens (B23), a compound eye lens (B24), an ultrafast reflector (B14), an ultrafast reflector (B16), a digital micromirror array (DMD) (B15), and a dichroic mirror (B17). The optical fiber collimator (B04) is used to emit the laser pulse in the optical switch (B01) in the form of quasi-parallel light. The compound eye lens group composed of the compound eye lens (B23) and the compound eye lens (B24) shapes the quasi-parallel Gaussian light into flat light. The shaped flat light is reflected by the ultrafast reflector (B14) to the surface of the DMD (B15). Under the control of the host computer, the flat-top light is shaped into various irregular light spots, and the shaped beam is reflected by the ultrafast reflector (B16) to the beam combining module, which outputs the beam uniformly.

[0051] In this embodiment, the irregular light spot is a non-circular light spot, which can be a triangle, a pentagon, a rectangle, or an irregular shape, such as an S-shape. Those skilled in the art can choose according to the specific situation, which will not be elaborated here.

[0052] Because the focal positions of beams with different shapes will have slight differences, in order to ensure that the focal position of the beam output from branch III of the beam shaping device remains in the same Z-axis plane as branches I and II, the DMD needs to introduce a quadratic phase function on the basis of the shaping function to form a virtual focal length, thus ensuring the accuracy of the focal position. Therefore, a virtual focal length needs to be introduced into the DMD. Its phase distribution It should meet the following requirements:

[0053] in, This represents the coordinates of each micromirror on the micromirror array; Indicates the center wavelength of the laser. This indicates the virtual focal length that needs to be generated; At this point, the virtual focal length and the light spot shape are linearly superimposed, and the phase is finally loaded onto the DMD. for:

[0054] in, To shape the phase of the light spot; For virtual lens phase, The carrier phase is used to spatially separate the +1 order signal light from the 0 order stray light; At this point, the focal length of branch III Virtual focal length of DMD and the physical focal length of the collimating lens Joint decision, namely:

[0055] because To fix the focal length, therefore adjust This allows for precise movement of the focal length along the Z-axis; at this point, the focal offset... and The relationship can be represented as:

[0056] The focus shift of different spot patterns This can be obtained through actual measurement, at which point:

[0057] The beam shaping device's beam combining module consists of an ultrafast reflector (B09), a half-wave plate (B19), a half-wave plate (B21), a half-wave plate (B18), a polarization beam splitter (B20), and a polarization beam splitter (B22). The half-wave plates (B19), (B21), and (B18) are mounted on an electrically rotating support, and their fast axis angle can be controlled by a host computer to control the beam polarization and achieve the beam combining function, so that all three branches are output from the same outlet.

[0058] Similarly, in other embodiments, half-wave plates (B19), (B21), and (B18) can be mounted on a mechanical rotating support, as long as they can rotate.

[0059] In this embodiment, the beam quality feedback device includes a beam splitter (C04), a motorized six-axis displacement stage (C05), an illumination device (C06), an autocorrelator (C03), an industrial camera (C02), and a host computer (C01). The beam splitter (C04) is an unbiased polarization beam splitter with a splitting ratio of 99:1. 99% of the beam is transmitted at one end and focused on the motorized six-axis displacement stage (C05) to achieve laser processing. The reflected laser pulse is calibrated and then enters the autocorrelator (C03). The host computer (C01) monitors the pulse shape and width and dynamically adjusts the relative distance between the transmission diffraction grating (A04) and the transmission diffraction grating (A03) to keep the laser pulse close to the transformation limit width.

[0060] In other embodiments, the beam splitting ratio of the beam splitter can be adjusted to other ratios, which can be selected according to the needs of the plot.

[0061] The electric six-axis displacement stage is used to place the components to be processed, and the components can also be placed on other types of platforms, such as multi-degree-of-freedom robotic arms.

[0062] Example 2 The working method of the system provided in Embodiment 1 includes the following steps: A pre-dispersion compensation device is used to provide negative group velocity dispersion to the laser pulse of the laser to counteract the pulse broadening generated by subsequent devices; The branch into which the laser pulse processed by the pre-dispersion compensation device enters is controlled by an optical switch; The first branch transmits the laser pulse as a line beam and focuses it on the surface of the object being processed, propagating it as a Bessel beam to achieve deep focal depth cutting. The second branch emits the laser pulse in the form of quasi-parallel light and changes the shape of the light pulse, shaping the Gaussian beam into a vortex beam or a Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with large focal depth. The third branch emits the laser pulse in the form of quasi-parallel light, and shapes the quasi-parallel Gaussian light into flat light, and shapes the flat-top light into irregular light spots; The beams from each branch are reflected to the beam combining module, which controls the beam polarization to achieve beam combining and output a unified beam. The beam quality feedback device splits the combined laser pulses into beams according to a predetermined splitting ratio. One beam is used for laser processing, and the other beam is used to monitor the pulse shape and width. Based on the monitoring results, the negative group velocity dispersion of the pre-dispersion compensation device is dynamically adjusted so that the laser pulse is always close to the transform limit width.

[0063] During operation, the focal position of the beam spot output from the third branch of the beam shaping device is kept in the same Z-axis plane as the first and second branches.

[0064] The third branch of the digital micromirror array introduces a quadratic phase function on the basis of the shaping function to form a virtual focal length. The virtual focal length is linearly superimposed with the light spot shape modulation to obtain the final phase loaded on the digital micromirror array.

[0065] Virtual focal length Its phase distribution It should meet the following requirements:

[0066] in, This represents the coordinates of each micromirror on the micromirror array; Indicates the center wavelength of the laser. This indicates the virtual focal length that needs to be generated.

[0067] Final phase for:

[0068] in, To shape the phase of the light spot; For virtual lens phase, The carrier phase is used to spatially separate the +1 order signal light from the 0 order stray light.

[0069] Focal length of the third branch Virtual focal length of digital micromirror array and the physical focal length of the collimating lens Joint decision, namely:

[0070] To fix the focal length, adjust To achieve focal length movement along the Z-axis, focus offset and The relationship is represented as:

[0071] Focus offset of different spot patterns Through actual measurement, it was found that at this time: .

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art without creative effort within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation, characterized in that, Includes a pre-dispersion compensation device, a beam shaping device, and a beam quality feedback device; The pre-dispersion compensation device is connected to the laser and is used to provide negative group velocity dispersion to the laser pulse of the laser to counteract the pulse broadening generated by the subsequent device. The beam shaping device includes three parallel branches and a beam combining module, and uses an optical switch to control the branch into which the laser pulse processed by the pre-dispersion compensation device enters. The first branch is used to transmit the laser pulse as a line beam and focus it on the surface of the object being processed, propagating it as a Bessel beam to achieve deep focal depth cutting. The second branch is used to emit laser pulses in the form of quasi-parallel light and change the shape of the light pulses, shaping the Gaussian beam into a vortex beam or a Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with large focal depth. The third branch is used to emit laser pulses in the form of quasi-parallel light, and to shape the quasi-parallel Gaussian light into flat light, and the flat-top light into irregular light spots; The beams from each branch are reflected to the beam combining module, which controls the beam polarization to achieve beam combining and output a unified beam. The beam quality feedback device is used to split the combined laser pulses according to a predetermined splitting ratio. One beam is used for laser processing, and the other beam is used to monitor the pulse shape and width. Based on the monitoring results, the negative group velocity dispersion of the pre-dispersion compensation device is dynamically adjusted so that the laser pulse is always close to the transform limit width.

2. The three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation as described in claim 1, characterized in that, The pre-dispersion compensation device includes an optical fiber collimator, a hollow roof prism, a transmission diffraction grating, and an ultrafast mirror. The spacing between the transmission diffraction gratings is adjustable. By adjusting the relative distance between them, the negative group velocity dispersion provided by the pre-dispersion compensation device is adjusted. The optical fiber collimator is used to collimate the spatial optical path and couple the spatial light back to the polarization-maintaining fiber. The transmission diffraction grating is a fixed grating, while the transmission diffraction grating is fixed on a movable mechanism, making it a movable grating.

3. The three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation as described in claim 1, characterized in that, The first branch includes a first fiber collimator, a first cylindrical mirror, a second cylindrical mirror, and a first conical lens. The first fiber collimator is used to emit the laser pulse in the optical switch in the form of quasi-parallel light. After passing through the first cylindrical mirror, the quasi-parallel light is focused in the vertical direction to form a line beam. Then, after passing through the second cylindrical mirror, the line beam is re-collimated in the vertical direction, so that the beam can be continuously transmitted in the form of a line beam. The first conical lens propagates the shaped line beam in the form of a Bessel beam to achieve large depth of focus cutting.

4. The three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation as described in claim 1, characterized in that, The second branch includes a second fiber collimator, a vortex waveplate, a second conical lens, a movable mechanism, and a plano-convex lens. The second fiber collimator is used to emit the laser pulse from the optical switch in the form of quasi-parallel light. The vortex waveplate and the second conical lens are fixed on the movable mechanism. By controlling the movable mechanism, the vortex waveplate or the second conical lens can change the shape of the light pulse, shaping the Gaussian beam into a vortex beam or a circular Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with large focal depth. The plano-convex lens is used to focus the vortex beam or the circular Bessel beam so that the focal point of the second branch is located on the same Z-axis plane as the linear light spot in the first branch.

5. The three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation as described in claim 1, characterized in that, The third branch includes a third fiber collimator, a first compound eye lens, a second compound eye lens, a first ultrafast reflector, a second ultrafast reflector, a digital micromirror array, and a dichroic mirror. The third fiber collimator is used to emit the laser pulse in the optical switch in the form of quasi-parallel light. The compound eye lens group composed of the first and second compound eye lenses shapes the quasi-parallel Gaussian light into flat light. The shaped flat light is reflected by the first ultrafast reflector to the surface of the digital micromirror array. Under the control of the host computer, the flat-top light is shaped into an irregular light spot, and the shaped beam is reflected by the second ultrafast reflector to the beam combining module, which outputs the beam uniformly.

6. The three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation as described in claim 1, characterized in that, The beam combining module includes a third ultrafast mirror, a first half-wave plate, a second half-wave plate, a third half-wave plate, a first polarizing beam splitter, and a second polarizing beam splitter. The third ultrafast mirror is located at the end of the first branch. The first half-wave plate is located between the third ultrafast mirror and the first polarizing beam splitter. The third half-wave plate is located at the end of the third branch. The second polarizing beam splitter is located at the rear end of the third half-wave plate. The second half-wave plate is located between the first polarizing beam splitter and the second polarizing beam splitter. The three half-wave plates are mounted on a rotatable mechanism. By controlling their fast axis angle, the beam polarization is controlled, thereby achieving the beam combining function and ensuring that all three branches output from the same outlet.

7. The three-channel parallel ultrafast laser shaping system based on spatiotemporal compensation as described in claim 1, characterized in that, The beam quality feedback device includes a beam splitter, a processing platform, lighting equipment, an autocorrelator, an industrial camera, and a host computer. The beam splitter is an unrelated polarization beam splitter, with one end transmitting and being focused on the processing platform to achieve laser processing. The reflected laser pulse is calibrated and then enters the autocorrelator. The host computer monitors the pulse shape and width and dynamically adjusts the relative distance between the transmission diffraction grating and the transmission diffraction grating based on the monitoring results, so that the laser pulse is always close to the transformation limit width.

8. A method of operating the system based on any one of claims 1-7, characterized in that, Includes the following steps: A pre-dispersion compensation device is used to provide negative group velocity dispersion to the laser pulse of the laser to counteract the pulse broadening generated by subsequent devices; The branch into which the laser pulse processed by the pre-dispersion compensation device enters is controlled by an optical switch; The first branch transmits the laser pulse as a line beam and focuses it on the surface of the object being processed, propagating it as a Bessel beam to achieve deep focal depth cutting. The second branch emits the laser pulse in the form of quasi-parallel light and changes the shape of the light pulse, shaping the Gaussian beam into a vortex beam or a Bessel beam. The vortex beam is used for hollow processing or optical tweezers, and the Bessel beam is used for drilling with large focal depth. The third branch emits the laser pulse in the form of quasi-parallel light, and shapes the quasi-parallel Gaussian light into flat light, and shapes the flat-top light into irregular light spots; The beams from each branch are reflected to the beam combining module, which controls the beam polarization to achieve beam combining and output a unified beam. The beam quality feedback device splits the combined laser pulses into beams according to a predetermined splitting ratio. One beam is used for laser processing, and the other beam is used to monitor the pulse shape and width. Based on the monitoring results, the negative group velocity dispersion of the pre-dispersion compensation device is dynamically adjusted so that the laser pulse is always close to the transform limit width.

9. The working method as described in claim 8, characterized in that, During operation, the focal position of the beam output from the third branch of the beam shaping device is kept in the same Z-axis plane as the first and second branches; The third branch of the digital micromirror array introduces a quadratic phase function on the basis of the shaping function to form a virtual focal length. The virtual focal length and the light spot shape are linearly superimposed to obtain the final phase loaded on the digital micromirror array. Virtual focal length Its phase distribution It should meet the following requirements: in, This represents the coordinates of each micromirror on the micromirror array; Indicates the center wavelength of the laser. This indicates the virtual focal length that needs to be generated; Final phase for: in, To shape the phase of the light spot; For virtual lens phase, The carrier phase is used to spatially separate the +1 order signal light from the 0 order stray light.

10. The working method as described in claim 9, characterized in that, Focal length of the third branch Virtual focal length of digital micromirror array and the physical focal length of the collimating lens Joint decision, namely: To fix the focal length, adjust To achieve focal length movement along the Z-axis, focus offset and The relationship is represented as: Focus offset of different spot patterns Through actual measurement, it was found that at this time: 。

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