A laser processing apparatus and a laser processing method

Abstract

The application discloses a laser processing device and a laser processing method, and relates to the field of laser processing.The device comprises a composite beam shaper, a diffraction optical element and a super surface.The diffraction optical element and the super surface are respectively located on two sides of the base.The composite beam shaper converts an incident light beam into a target flat-top light beam by changing at least one of the length of a super atom in the super surface in two orthogonal directions, the azimuth angle of the super atom and the height of a structural unit in the diffraction optical element, and adjusting the phase distribution of the composite beam shaper.By combining the diffraction optical element and the super surface, a composite beam shaping device is generated, so that the laser Gaussian energy distribution is shaped into a flat-top uniform energy distribution.The composite beam shaping device is used to replace the beam shaping element and the objective lens in the traditional laser processing system, so that the problems, such as large volume and complex optical path, inherent in the traditional beam shaping system can be solved, and the miniaturization and integration of the processing device are realized.

Description

Technical Field

[0001] This application relates to the field of laser processing, specifically to a laser processing apparatus and a laser processing method. Background Technology

[0002] In laser processing, the characteristics of the laser beam play a crucial role in determining the quality and performance of the manufactured parts. Gaussian beams, whose energy distribution resembles a Gaussian curve, are widely used in laser systems. Due to their excellent beam quality, low divergence, and high spatial coherence, Gaussian beams have become an ideal choice for laser processing applications.

[0003] However, with the development of laser processing technology and the increasing demand for higher productivity and high-quality workpieces, the limitations of traditional Gaussian beams have become increasingly apparent. These limitations stem from the steep energy gradient of the beam spreading outward from the center, directly affecting process stability, productivity, mechanical properties, surface roughness, and the microstructure of manufactured parts. Therefore, spatial beam shaping technology is urgently needed to regulate laser intensity into a uniform spatial distribution.

[0004] Existing laser shaping systems typically consist of beam homogenizers or spatial light modulators. These systems occupy a large volume of space, have complex optical path designs, and require cumbersome debugging processes. Summary of the Invention

[0005] To address the aforementioned problems, this application proposes a laser processing apparatus, comprising:

[0006] A composite beam shaper includes a substrate, a diffractive optical element, and a metasurface, wherein the diffractive optical element and the metasurface are located on opposite sides of the substrate. The composite beam shaper modulates the phase distribution of the composite beam shaper by changing at least one of the length of the superatoms in two orthogonal directions, the azimuth angle of the superatoms, and the height of the structural units in the diffractive optical element, thereby converting the incident beam into a target flat-top beam.

[0007] In one example, the phase expression for the left-hand circularly polarized component in the output field of the composite beam shaper is:

[0008]

[0009] in, Here is the phase expression for the left-hand circularly polarized component. , is the transport phase of the superatom. The effective refractive index represents the superatom, and its magnitude is related to the length of the superatom in the two orthogonal directions within the metasurface. Indicates the height of the superatom; This provides phase compensation for diffractive optical elements and for compound beam shapers. The effective refractive index of the internal structural unit of the diffractive optical element. The height of the structural unit of the diffractive optical element; The azimuth angle of the superatom.

[0010] In one example, the phase expression for the right-hand circularly polarized component in the exit field of the composite beam shaper is:

[0011]

[0012] in, This is the phase expression for the right-hand circularly polarized component. , is the transport phase of the superatom. The effective refractive index represents the structural unit, and its magnitude is related to the lengths of the superatoms within the metasurface in two orthogonal directions. Indicates the height of the superatom; This provides phase compensation for diffractive optical elements and for compound beam shapers. The effective refractive index of the internal structural unit of the diffractive optical element. The height of the structural unit of the diffractive optical element; The azimuth angle of the superatom.

[0013] In one example, the substrate, the diffractive optical element, and the metasurface are all made of dielectric materials.

[0014] In one example, the superatomic structure in the metasurface is rectangular or elliptical; the period of the superatoms in the metasurface is 660 nm and the height is 900 nm; the period of the diffractive optical element is 660 nm.

[0015] In one example, the laser processing apparatus further includes at least one of a beam expander, a waveplate group, and a three-axis displacement platform; the beam expander is used to enlarge the spot of the incident laser to a preset size; the waveplate group is used to adjust the polarization state of the incident laser to the circular polarization type of the incident laser, the circular polarization type including at least one of left-handed circular polarization and right-handed circular polarization; the three-axis displacement platform is used to control the movement of the workpiece to be processed.

[0016] In one example, the waveplate group includes at least one of a half-wave plate and a quarter-wave plate.

[0017] This application also provides a laser processing method applied to the laser processing apparatus described in any of the above examples. The method includes: determining the holographic phase of the target flat-top beam based on the shape of the target flat-top beam; determining composite beam shaper parameters based on the circularly polarized light type of the target flat-top beam and the holographic phase; the composite beam shaper parameters include at least one of the length of the superatoms in two orthogonal directions within the metasurface, the superatom azimuth angle, and the height of the structural unit within the diffractive optical element.

[0018] In one example, determining the parameters of the composite beam shaper based on the circularly polarized light type of the target flat-top beam and the holographic phase specifically includes: determining the lens phases corresponding to the left and right circularly rotating components of the output field of the composite beam shaper based on the focal length and the wavelength of the incident light source; and determining the parameters of the composite beam shaper based on the lens phases, the holographic phase, and the circularly polarized light type.

[0019] In one example, the expression for the lens phase is:

[0020]

[0021] in, For the lens phase, Focal length , where is the radius corresponding to the lens phase; This indicates the wavelength of the incident light source.

[0022] The method proposed in this application can bring the following beneficial effects:

[0023] 1. By combining diffractive optical elements with metasurfaces, a composite beam shaping device is generated, thereby shaping the laser Gaussian energy distribution into a flat-top uniform energy distribution.

[0024] 2. Replacing the beam shaping elements, 4f system and objective lens in the traditional laser processing system with a composite beam shaping device can solve the inherent problems of large size and complex optical path of the traditional beam shaping system, and realize the miniaturization and integration of the processing device.

[0025] 3. By using diffractive optical elements to compensate for the phase transmission of low-refractive-index metasurfaces and combining the spin decoupling characteristics of metasurfaces, dual-channel flat-top beam generation is achieved by independently encoding the phases of the left-hand and right-hand circularly polarized components of the outgoing field. This solves the problems of the single beam shaping function of traditional diffractive optical elements and the incomplete phase control of metasurfaces composed of low-refractive-index media.

[0026] 4. The phase transmission of low-refractive-index metasurfaces is supplemented by using diffractive optical elements, thereby improving the phase modulation capability. Attached Figure Description

[0027] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0028] Figure 1 This is a schematic diagram of the composite beam shaper in the embodiments of this application;

[0029] Figure 2 This is a schematic diagram of a metasurface structure in an embodiment of this application;

[0030] Figure 3 This is a schematic diagram of a diffractive optical element structure in an embodiment of this application;

[0031] Figure 4 This is a schematic diagram of the structure of a laser processing apparatus according to an embodiment of this application;

[0032] Figure 5 This is a schematic diagram of each phase in a composite beam shaper according to an embodiment of this application;

[0033] Figure 6 This is a schematic diagram of the incident Gaussian light intensity energy distribution in an embodiment of this application;

[0034] Figure 7 This is a schematic diagram of the phase distribution of a circular and a square flat-top optical hologram in an embodiment of this application;

[0035] Figure 8 This is a schematic diagram of the lens phase distribution in an embodiment of this application;

[0036] Figure 9 This is a schematic diagram of the light intensity distribution of a circular and a square flat-topped light source in an embodiment of this application.

[0037] Among them, 1. Laser source, 2. Beam expander, 3. Half-wave plate, 4. Quarter-wave plate, 5. Reflector, 6. Metasurface composite beam shaper, 7. Workpiece, 8. Triaxial displacement platform. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0040] Figure 1 This specification provides a composite beam shaper in a laser processing apparatus, comprising a substrate, a diffractive optical element, and a metasurface, wherein the diffractive optical element and the metasurface are located on opposite sides of the substrate. The diffractive optical element is located on the upper side of the substrate, and the metasurface is located on the lower side of the substrate. In fabricating this composite beam shaper, the structure of the diffractive optical element can be first etched into the raw material. Then, a coating is applied to the back of the diffractive optical element using a deposition equipment such as PECVD, with the layer thickness being the same as the designed height of the metasurface. Subsequently, the metasurface structure is etched onto the coating using methods such as EBL.

[0041] This composite beam shaper can reshape the Gaussian energy distribution of a laser into a flat-topped uniform energy distribution. Specifically, it can convert the incident beam into a target flat-topped beam by changing at least one of the following: the length of the superatoms in two orthogonal directions within the metasurface, the azimuth angle of the superatoms, and the height of the structural unit within the diffractive optical element. Here, the superatoms refer to the densely packed nanopillar structures on the surface of the metasurface. The principle of this composite beam shaper is explained below:

[0042] The Jones matrix of a superatom in a known metasurface can be represented as:

[0043] (1)

[0044] in This represents the phase delay of each superatom along its major and minor axes. For the transport phase of superatoms, The effective refractive index of the superatom is expressed as the length of the superatom in the two orthogonal directions within the metasurface. , )related, Indicates the height of the superatom. This represents the azimuth angle of the superatom. Wherein, , , , For reference, please see below. Figure 2 The diagram shows a metasurface structure.

[0045] When using the incident phase delay of circularly polarized light When the half-wave plate is superatomic, the transmitted light field can be expressed as:

[0046] (2)

[0047] (3)

[0048] in, and These represent left-handed and right-handed circularly polarized light, respectively. and Let the phases of the left-handed and right-handed circularly polarized components in the output field be represented by the following expressions:

[0049] (4)

[0050] (5)

[0051] Therefore, by changing the azimuth angle The geometric phase can be adjusted to independently encode the phases of the left-hand and right-hand circularly polarized components of the outgoing field, thus achieving spin decoupling.

[0052] Although this method is applicable to most dielectric metasurfaces, it cannot achieve complete control of the transport phase within a limited superatomic size range for low-refractive-index dielectric metasurfaces. Therefore, this scheme addresses this issue by... Figure 3 The diffractive optical element shown is integrated with a metasurface to compensate for the metasurface's transmission phase, achieving complete transmission phase modulation and circular polarization spin decoupling. The compensated phase of the diffractive optical element is expressed by equation (6):

[0053] (6)

[0054] in Let be the height of the structural unit of the diffractive optical element. When the diffractive optical element is integrated with the metasurface, equations (4) and (5) become:

[0055] (7)

[0056] (8)

[0057] That is, the height of the structural unit of the diffractive optical element can be changed. Transmission phase compensation is performed, while the metasurface retains its spin decoupling capability of independently encoding the phases of the left-hand and right-hand circularly polarized components of the outgoing field.

[0058] In the embodiments provided in this application, the substrate, diffractive optical element, and metasurface material of the above-mentioned composite beam shaper are dielectric materials, which can be diamond, fused silica, silicon carbide, silicon nitride, single crystal silicon, amorphous silicon, fused amorphous silicon, titanium dioxide, etc.

[0059] In one embodiment, height can be adjusted and cycle Perform a parameter scan and select a half-wave plate functional superatom that meets the requirements. When or When the phase modulation capability is small, it is difficult to select a half-wave plate functional superatom that meets the requirements; when or When the density is large, it significantly reduces the transmittance of superatoms, thus decreasing energy efficiency. Therefore, coordinated adjustments are needed. and Under the premise of ensuring high transmittance, functional superatoms of half-wave plates that meet the conditions were screened out. The superatomic structure in this metasurface is rectangular or elliptical; the periodicity of the superatoms in the metasurface is... The wavelength is 660 nm, and the height is fixed at 900 nm; the period of the diffractive optical element is... It is 660nm. The superatomic period can be seen in... Figure 2 ,in Used to indicate the length occupied by each superatom.

[0060] In one embodiment, the laser processing apparatus further includes components such as a beam expander, a waveplate group, and a three-axis displacement platform. The beam expander is used to enlarge the incident laser spot to a preset size; the waveplate group is used to adjust the polarization state of the incident laser to the circularly polarized light type, where the circularly polarized light type includes at least one of left-handed and right-handed circularly polarized light; and the three-axis displacement platform is used to control the movement of the workpiece to be processed.

[0061] This application provides a laser processing apparatus based on a composite beam shaping device of diffractive optical elements and metasurfaces, as shown in the attached document. Figure 9 As shown, after the laser light source 1 is emitted, the laser spot is enlarged to the required size by the beam expander 2. The laser polarization state is adjusted to left-hand circular polarization by the half-wave plate 3 and the quarter-wave plate 4. After passing through the reflector 5 and the diffractive optical element and the metasurface composite beam shaper 6, a flat-top beam is generated. The flat-top beam is focused on the workpiece 7 for processing. The sample movement is controlled by adjusting the three-axis displacement platform 8.

[0062] According to the actual processing needs, first adjust the half-wave plate 3 to adjust the polarization state of the incident light to horizontal polarization. Then rotate the quarter-wave plate 4 so that its fast axis makes an angle of 45° with the horizontal direction. At this time, the linearly polarized light is converted into right-hand circularly polarized light. After passing through the metasurface composite beam shaper 6, a circular flat-top beam is generated. Continue to rotate the quarter-wave plate 4. When its fast axis makes an angle of -45° with the horizontal direction, the right-hand circularly polarized light is converted into left-hand circularly polarized light. After passing through the metasurface composite beam shaper 6, a square flat-top beam is generated, thereby realizing the function switching of the composite beam shaper.

[0063] This application also provides a laser processing method, including:

[0064] S101: Determine the holographic phase of the target flat-top beam based on its shape.

[0065] First, determine the shape of the target beam to identify its two-dimensional form (e.g., circle, square, triangle, hexagon, etc.; circle and square are used as examples here). Then, based on the shape and energy distribution of the circular and square flat-top beams, the holographic phase of the two types of target flat-top beams can be obtained using phase analysis or phase retrieval algorithms. Here, the holographic phase of the circular flat-top beam is represented as... The holographic phase of the square flat-top beam is represented as .

[0066] S102: Determine the parameters of the composite beam shaper based on the circularly polarized light type of the target flat-top beam and the holographic phase.

[0067] Knowing the holographic phase, the two-variable linear equation can be determined based on the representation of the left-hand and right-hand circularly polarized light of the target flat-top beam as shown in equations (7) and (8), and the holographic phase, thereby solving for the parameters of the composite beam shaper. Here, the composite beam shaper parameters include at least one of the structural unit height, superatom height, and superatom azimuth angle of the diffractive optical element. Specifically, when solving, the parameters can be... As a whole, at the same time as well as Solve the problem.

[0068] In one embodiment, compared to traditional processing systems that require lenses or objectives for focusing after passing through the shaping element, this solution integrates the lens phase into the composite element, eliminating the need for lenses or objectives. This allows the light beam to be focused immediately after passing through the composite element, simplifying the optical path and reducing alignment errors. The lens phase can then be expressed as: , is the radius The function, Indicates focal length. This represents the wavelength of the incident light source. The phases of the outgoing left-handed and right-handed circularly polarized components are designed as follows:

[0069] (9)

[0070] (10)

[0071] in, The lens phase corresponding to the left-hand circular polarization component has a corresponding focal length of . ; The lens phase corresponding to the right-hand circular polarization component has a corresponding focal length of . By adding diffractive optical elements and changing the height of the structural units of the diffractive optical elements, the transport phase of the metasurface can be compensated, thus enabling complete control of the transport phase of the metasurface in low refractive index media.

[0072] The design method of a structural unit in a composite component is now described in detail: the result calculated by equations (9) and (10) for a specific point The phase is , Combining equations (7) and (8), we can obtain:

[0073]

[0074]

[0075] Calculation yields: , The diffractive optical elements and metasurface composite elements together form eight pairs of transmission phase modulation units, capable of covering 0-2 Complete modulation of the transmission phase, with an increment of approximately 0.25. ,like Figure 5 As shown by the dotted line in the middle star shape. Therefore, a phase adjustment value of 1.5 is chosen. The unit cell structure modulates this transmission phase. At this point, the superatomic... , The height of the diffractive optical element is Additionally, the orientation angle of the superatom needs to be set to 0.1325. To achieve the control of geometric phase.

[0076] Figure 1 The diagram shows a composite structure of diffractive optical elements and metasurface elements. The lower layer is a metasurface, which independently encodes left-handed and right-handed circularly polarized light, expanding the optical field modulation function. The upper layer is a diffractive optical element, which achieves full phase modulation by adjusting the height of the structural units.

[0077] Figure 2 Detailed schematic diagrams of the metasurface and its unit cell structure in the composite element are shown. Fused silica serves as the substrate, and the metaatomic material is anisotropic silicon carbide. The periodicity of the metaatoms... The superatomic transport phase is determined by... or This indicates that the height of the fixed superatom is... By changing the lengths of the two orthogonal directions of the superatom and Adjusting the effective refractive index or This allows control over its transmission phase, while simultaneously modulating the superatomic phase delay. Changes; the geometric phase is controlled by altering the azimuth angle of the rectangular silicon carbide superatoms.

[0078] Figure 3A detailed schematic diagram of the diffractive optical element and its unit structure in the composite element is shown. The element is made of fused silica, and the periodicity is... The structural units fill the entire cycle, and the height of the structural units is changed. The phase of the metasurface is compensated by controlling the phase change of the transmission phase.

[0079] Based on superatomic transport phase and phase delay Based on the calculation results, three phase delays were selected. Furthermore, superatoms with different transport phases serve as structural units of the metasurface, as shown in the attached figure. Figure 4 The square dotted line (representing the phase delay of the superatom) The diagram shows the phase transition (0-2) and dots (representing the transport phase). Because the transport phase of these three superatoms cannot be achieved in the 0-2 range... Complete phase modulation was achieved, therefore, diffractive optical elements with five unit cell structures were designed to compensate for the transmission phase, such as... Figure 5 As shown in the triangular point. Finally, the diffractive optical elements and metasurface composite elements form eight pairs of transmission phase modulation units, capable of achieving coverage. Complete modulation of the transmission phase, with an increment of approximately ,like Figure 5 As shown in the star-shaped dotted line.

[0080] To verify the design, simulations were performed using MATLAB. The incident light wavelength was 1030 nm, and the waist radius of the Gaussian beam was 3 mm. Figure 6 As shown. and The circular and square holographic phase distributions, respectively, were calculated using the optimized GS algorithm. Figure 7 As shown; lens phase The focal length is set to 30mm, such as Figure 8 As shown. When right-handed and left-handed circularly polarized light are incident, circular and square flat-top beams with uniform energy distribution are generated at the focal plane, respectively, as shown. Figure 9 As shown.

[0081] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device and medium embodiments are basically similar to the method embodiments, so they are described more simply; relevant parts can be referred to the descriptions of the method embodiments.

[0082] The devices and media provided in this application are one-to-one with the methods. Therefore, the devices and media also have similar beneficial technical effects as their corresponding methods. Since the beneficial technical effects of the methods have been described in detail above, the beneficial technical effects of the devices and media will not be repeated here.

[0083] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0084] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0085] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0086] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0087] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0088] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0089] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0090] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0091] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A laser processing apparatus, characterized in that, include: A composite beam shaper includes a substrate, a diffractive optical element, and a metasurface, wherein the diffractive optical element and the metasurface are located on opposite sides of the substrate. The composite beam shaper modulates the phase distribution of the composite beam shaper by changing at least one of the length of the superatoms in the two orthogonal directions, the superatom azimuth angle, and the height of the structural unit in the diffractive optical element, thereby converting the incident beam into a target flat-top beam. The phase expression for the left-hand circularly polarized component in the output field of the composite beam shaper is: in, Here is the phase expression for the left-hand circularly polarized component. , is the transport phase of the superatom. The effective refractive index represents the superatom, and its magnitude is related to the length of the superatom in the two orthogonal directions within the metasurface. Indicates the height of the superatom; This provides phase compensation for diffractive optical elements and composite beam shapers. The effective refractive index of the internal structural unit of the diffractive optical element. The height of the structural unit of the diffractive optical element; The azimuth angle of the superatom; The phase expression for the right-hand circularly polarized component in the output field of the composite beam shaper is: in, Here is the phase expression for the right-hand circularly polarized component. , is the transport phase of the superatom. The effective refractive index represents the structural unit, and its magnitude is related to the lengths of the superatoms within the metasurface in two orthogonal directions. Indicates the height of the superatom; This provides phase compensation for diffractive optical elements and composite beam shapers. The effective refractive index of the internal structural unit of the diffractive optical element. The height of the structural unit of the diffractive optical element; The azimuth angle of the superatom.

2. The laser processing apparatus according to claim 1, characterized in that, The substrate, the diffractive optical element, and the metasurface are all made of dielectric materials.

3. The laser processing apparatus according to claim 1, characterized in that, The meta-atomic structure in the metasurface is rectangular or elliptical; The period of the superatoms in the metasurface is 660 nm, and the height is 900 nm. The period of the diffractive optical element is 660 nm.

4. The laser processing apparatus according to claim 1, characterized in that, The laser processing device further includes at least one of: a beam expander, a waveplate group, and a triaxial displacement platform; The beam expander is used to enlarge the spot of the incident laser to a preset size; The waveplate group is used to adjust the polarization state of the incident laser to the circular polarization type of the incident laser, wherein the circular polarization type includes at least one of left-handed circular polarization and right-handed circular polarization; The three-axis displacement platform is used to control the movement of the workpiece to be processed.

5. The laser processing apparatus according to claim 4, characterized in that, The waveplate group includes at least one of a half-wave plate and a quarter-wave plate.

6. A laser processing method, characterized in that, The method, applied to the laser processing apparatus as described in any one of claims 1-5, comprises: The holographic phase of the target flat-top beam is determined based on its shape. Based on the circularly polarized light type of the target flat-top beam and the holographic phase, the parameters of the composite beam shaper are determined; The parameters of the composite beam shaper include at least one of the following: the length of the superatoms in the metasurface in two orthogonal directions, the superatom azimuth angle, and the height of the structural unit within the diffractive optical element.

7. The method according to claim 6, characterized in that, The determination of the composite beam shaper parameters based on the circularly polarized light type of the target flat-top beam and the holographic phase specifically includes: Based on the focal length and the wavelength of the incident light source, the lens phases corresponding to the left and right circular components of the output field of the composite beam shaper are determined respectively. Based on the lens phase, the holographic phase, and the circularly polarized light type, the parameters of the composite beam shaper are determined.

8. The method according to claim 7, characterized in that, The expression for the lens phase is: in, For the lens phase, Focal length , where is the radius corresponding to the lens phase; This indicates the wavelength of the incident light source.

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