A micro-nano optical system for high-power laser parallel processing

Abstract

The present application relates to a kind of micro-nano optical systems for high-power laser parallel processing, it includes sequentially arranged beam splitting diffractive optical element, convex lens and super surface lens array;The beam splitting diffractive optical element is composed of wide band gap semiconductor material and / or high melting point inorganic non-metallic material, multiple microstructures on the beam splitting diffractive optical element are arranged relative to laser source, and multiple sub-beams are emitted on the convex lens after being split by laser beam;The super surface lens array is composed of wide band gap semiconductor material and / or high refractive inorganic non-metallic material, multiple super surface units on the super surface lens array are respectively arranged one-to-one corresponding with multiple sub-beams emitted by the convex lens, and multiple sub-beams are focused on workpiece.The present application realizes high-density multi-channel laser parallel output, has excellent thermal stability and high-power laser resistance, and is suitable for high-power continuous laser or high-repetition frequency pulse laser processing.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a micro-nano optical system for parallel processing with high-power lasers. Background Technology

[0002] Laser processing technology is an engineering technology that utilizes the interaction between a high-power-density laser beam and materials to achieve processes such as cutting, welding, drilling, and surface treatment. It is primarily applied in the automotive, electronics, electrical appliance, aerospace, metallurgy, and machinery manufacturing industries. Composed of a laser, optical system, machine tool, and control system, it encompasses diverse processes including laser cutting, welding, and marking. It features non-contact processing, a small heat-affected zone, and precision down to 0.1 mm, significantly improving labor productivity and automation while reducing material consumption. In laser precision machining, traditional single-beam laser point-by-point processing methods are increasingly unable to meet the demands of high-throughput and high-efficiency industrial production. Multi-beam parallel processing technology can effectively improve processing efficiency. Existing parallel processing technologies mainly include in-lens splitting parallel processing schemes based on microlens arrays (MLAs), spatial light modulators (SLMs), and diffractive optical elements (DOEs). This involves splitting a single femtosecond laser beam into multiple femtosecond laser beams with small spacing using these beam-splitting devices, and then introducing them into the same objective lens to achieve multi-focal parallel processing.

[0003] Chinese Patent CN114326322B discloses a high-throughput super-resolution laser direct-writing system based on a microlens array and a DMD, including a laser, a microlens array, a four-beam beam splitter, two beam multiplication units, a planar beam shifting element, a two-beam combiner, and multiple 4f systems; the multiple 4f systems include objective lenses; the four-beam beam splitter consists of three two-beam beam splitters; the laser beam output is split into m×m sub-beams by the microlens array, then enters the four-beam beam splitter and is split into four m×m beams of equal intensity; the four beams... In the beam splitter, two beams emitted from the same dual-beam beam splitter enter the same beam multiplier unit. Each beam multiplier unit outputs two 2m×m beams, which enter together in a dual-beam combiner. After beam combining, a 2m×2m focal point array is formed on the focal plane of the objective lens. The beam multiplier unit consists of two DMDs, a planar beam shifting element, and a dual-beam combiner. The two m×m beams enter the two DMDs respectively, and the intensity of each sub-beam is independently controlled. The beam emitted from one of the DMDs passes through the planar beam shifting element, and finally the two beams are combined in the dual-beam combiner. The above system achieves multi-channel laser output through a microlens array, but it suffers from low system integration, bulky structure, and poor beam uniformity. In practical applications, due to the lack of high integration in the system architecture, it is often difficult to achieve a balance between compact design and high-channel parallel output, which restricts its widespread application in batch and large-scale laser processing scenarios.

[0004] Chinese Patent CN113369674A discloses a parallel laser processing system, comprising a laser, a beam expander, a half-wave plate, a total internal reflection prism system, a spatial light modulator, a reflector, and a scanning processing unit for processing the product to be processed, arranged sequentially along the optical path. The total internal reflection prism system includes a first total internal reflection prism and a second total internal reflection prism. The contact surfaces of the first and second total internal reflection prisms form an inclined incident surface. The laser beam emitted from the laser is expanded by the beam expander and deflected by the half-wave plate before entering the incident surface of the total internal reflection prism system. After total internal reflection at the incident surface, the beam exits to the spatial light modulator. The incident angle between the beam totally reflected to the spatial light modulator and the spatial light modulator is 0-5 degrees. The diffracted beam modulated by the spatial light modulator passes sequentially through the first and second total internal reflection prisms and enters the reflector, and is reflected by the reflector to the scanning processing unit. The aforementioned systems use electronic light control devices such as spatial modulators for dynamic beam splitting or pattern reconstruction. Although they are highly flexible, their laser damage threshold is low, and they are usually unable to withstand continuous or pulsed laser power of hundreds of watts or more. At the same time, SLM devices generally have large power consumption and cooling requirements, and do not have sufficient stability and cost-effectiveness in industrial settings.

[0005] Chinese patent CN118989567A discloses a laser scanning device for multi-beam parallel processing, comprising a laser, a diffraction beam splitter, a collimating mirror, a motor, and a reflector. The laser's output port is positioned directly opposite the input port of the diffraction beam splitter. The collimating mirror is positioned between the reflector and the diffraction beam splitter. The diffraction beam splitter splits the laser beam into multiple beams, which then illuminate the collimating mirror. The reflector reflects the light transmitted through the collimating mirror onto the sample. The motor's shaft is fixed to the side surface of the reflector. This device splits the incident laser beam into multiple sub-beams using the diffraction beam splitter, and then uses different focusing mechanisms to simultaneously irradiate multiple processing points. While this method improves processing efficiency to some extent, traditional DOEs are typically made of materials such as quartz or photolithographic glass. These materials are prone to thermal distortion, ablation, and even optical failure under high-intensity laser irradiation, making long-term stable operation difficult and posing numerous challenges in high-power laser scenarios.

[0006] To focus multiple laser sub-beams after beam splitting, the aforementioned systems typically require complex relay optical systems, such as multiple aligned objective arrays or telescope systems. This not only increases the system size but also significantly raises the complexity of optical path design and debugging. Due to the lack of integrated structures suitable for high-power lasers, most parallel processing systems struggle to simultaneously achieve high power handling capacity, high spot uniformity, and miniaturized integration, limiting their applications. The presence of multiple independent optical components requiring assembly and calibration further increases manufacturing and usage costs and restricts the consistency and reliability of the device. Therefore, traditional technical solutions cannot fundamentally overcome the structural bottleneck of simultaneously satisfying "power, parallelism, and compactness" in high-power laser processing. Summary of the Invention

[0007] The problem to be solved by the present invention is to provide a micro-nano optical system for high-power laser parallel processing, which addresses the above-mentioned deficiencies in the prior art. By integrating and optimizing DOE and MLA schemes, it can efficiently split and accurately focus a single laser beam, realize high-density multi-channel laser parallel output, and has excellent thermal stability and resistance to high-power lasers. It is suitable for high-power continuous laser or high-repetition-frequency pulsed laser processing.

[0008] The above-mentioned objective of this invention is achieved through the following technical solutions:

[0009] A micro / nano optical system for high-power laser parallel processing includes sequentially arranged beam-splitting diffraction optical elements, a convex lens, and a metasurface lens array. The beam-splitting diffraction optical elements are composed of wide-bandgap semiconductor materials and / or high-melting-point inorganic non-metallic materials. Multiple microstructures on the beam-splitting diffraction optical elements are arranged relative to the laser source and split the laser beam into multiple sub-beams, which are then emitted onto the convex lens. The metasurface lens array is composed of wide-bandgap semiconductor materials and / or high-refractive-index inorganic non-metallic materials. Multiple metasurface units on the metasurface lens array are arranged in a one-to-one correspondence with the multiple sub-beams emitted from the convex lens and focus the multiple sub-beams onto the workpiece.

[0010] Furthermore, the beam-splitting diffraction optical element is composed of one or more of diamond, SiC, AlN, Al2O3, MgO, CaF2, LiF, fused silica, optical ceramics, and composite crystals.

[0011] Furthermore, the substrate thickness L of the beam-splitting diffraction optical element satisfies the following conditions: ;in, The wavelength of the laser. For the thermal conductivity of beam-splitting diffraction optical elements, As a safety factor, The average power of the laser. The absorption coefficient of a beam-splitting diffraction optical element. The temperature coefficient of refractive index. The refractive index of a beam-splitting diffraction optical element. is the coefficient of thermal expansion.

[0012] Furthermore, the substrate material of the beam-splitting diffraction optical element is 4H-SiC with a thickness of 300~500μm, so that the wavefront distortion of the beam-splitting diffraction optical element does not exceed [the specified value]. .

[0013] Furthermore, the microstructure of the beam-splitting diffraction optical element is highly... satisfy, ;in, The coordinates of the distance between the microstructure and the center of the beam-splitting diffraction optical element are... The wavelength of the laser. The refractive index of the substrate is... This represents the total number of phase steps within the microstructure period. For quantization series.

[0014] Furthermore, the phase distribution of the beam-splitting diffraction optical element Far-field amplitude of the target The interval is satisfied. ;in, For Fourier transform operators, The amplitude distribution of the incident laser beam. It is the imaginary unit.

[0015] Furthermore, the metasurface lens array is made of one or more of the following materials: SiC, TiO2, Nb2O5, Ta2O5, Si3N4, ZnS, and diamond.

[0016] Furthermore, the phase distribution of the metasurface unit satisfy, ;in, The wavelength of the laser. Focal length , The coordinates are the distance between the nanopillar and the center of the metasurface unit.

[0017] Furthermore, the metasurface unit achieves phase distribution by establishing a nanopillar diameter-phase mapping database. Phase mapping model satisfy, ;in, The wavelength of the laser. For equivalent refractive index, the diameter of the nanopillar is... =0~500nm, nanopillar height =1μm.

[0018] Furthermore, the evaluation function of the metasurface lens array for, ;in, For diffraction efficiency, and As the weighting coefficient, set > , denoted as the root mean square error of the energy of all sub-beams.

[0019] In summary, the beneficial technical effects of the present invention are as follows:

[0020] 1. The micro-nano optical system of this invention consists of a beam-splitting diffraction optical element, a convex lens, and a metasurface lens array, performing functions such as laser beam splitting, control, and focusing. It boasts advantages such as compact structure, short optical path, high channel count, high energy efficiency, and strong manufacturing consistency. This system is not only suitable for static multi-point processing but can also integrate dynamic scanning, beam shaping, and wavefront control modules, exhibiting broad technical compatibility.

[0021] 2. The beam-splitting diffraction optical element of the present invention has excellent thermal stability and resistance to high-power lasers, and is suitable for high-power continuous lasers or high-repetition-frequency pulsed laser systems. By integrating this beam-splitting diffraction optical element and a metasurface lens array, a single laser beam can be efficiently split and precisely focused to achieve high-density multi-channel laser parallel processing.

[0022] 3. The beam-splitting diffraction optical element and metasurface lens array of the present invention can be realized in a large area array structure using wafer-level micro-nano manufacturing process, and have good device consistency and scalability, making them suitable for industrial mass production needs;

[0023] 4. The micro-nano optical system of the present invention does not require a relay optical telescope or beam expander system. The overall structure is compact and easy to integrate into the front end of laser processing equipment, which improves the miniaturization of the system. Each beam is focused by an independent metasurface unit to form a small spot with a high numerical aperture, realizing diffraction-limited micro-processing, balancing processing efficiency and precision. Moreover, the whole is a passive optical structure, which does not require electronic control drive and is not affected by electromagnetic interference, making it suitable for high stability and high reliability scenarios. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the micro-nano optical system of Embodiment 1 of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the beam-splitting diffraction optical element in Embodiment 2 of the present invention.

[0026] Figure 3 This is a schematic diagram of the metasurface lens array of Embodiment 3 of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure and a diagram of the beam-splitting effect of the beam-splitting diffraction optical element of Embodiment 4 of the present invention.

[0028] Figure 5 This is a schematic diagram of the structure of multiple beam-splitting diffraction optical elements in Embodiment 4 of the present invention.

[0029] Figure 6 This is a schematic diagram of the structure of multiple metasurface units in Embodiment 4 of the present invention.

[0030] Figure 7 This is a schematic diagram of the metasurface lens array of Embodiment 4 of the present invention.

[0031] In the figure, 1 is a beam-splitting diffraction optical element; 11 is a substrate; 12 is a microstructure; 2 is a convex lens; 3 is a metasurface lens array; 31 is a substrate; 32 is a metasurface unit; and 33 is a nanopillar. Detailed Implementation

[0032] To make the technical means, creative features, objectives and effects of this invention clearer and easier to understand, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example 1: Refer to Figure 1 This invention discloses a micro-nano optical system for high-power laser parallel processing, comprising a beam-splitting diffraction optical element 1, a convex lens 2, and a metasurface lens array 3 arranged sequentially. The beam-splitting diffraction optical element 1 is composed of a wide-bandgap semiconductor material and / or a high-melting-point inorganic non-metallic material. Multiple microstructures 12 on the beam-splitting diffraction optical element 1 are arranged relative to the laser source and split the laser beam into multiple sub-beams, which are then emitted onto the convex lens 2. The metasurface lens array 3 is composed of a wide-bandgap semiconductor material and / or a high-refractive-index inorganic non-metallic material. Multiple metasurface units 32 on the metasurface lens array 3 are arranged in a one-to-one correspondence with the multiple sub-beams emitted from the convex lens 2, focusing the multiple sub-beams onto the workpiece.

[0034] In the micro-nano optical system of the present invention, the laser beam can be Gaussian distributed, flat-top distributed, elliptical beam, linear beam, etc., and the laser spot can be a dot array, linear array, curved surface array, rotating structure, etc. The output spot size ranges from 200nm to 2cm, the spot spacing is adjustable from several micrometers to several centimeters, and the number of output laser channels can reach hundreds or even thousands. The micro-nano optical system can be combined with high-speed scanning mirrors, spatial light modulators (SLM / DMD), variable focus platforms or MEMS micro-mirror arrays to support dynamic control or rapid reconstruction of processing patterns.

[0035] The micro-nano optical system of the present invention can be modularly installed in industrial laser heads, processing platforms, lithography systems, laser projection systems, optical micromachining equipment or wafer processing devices, and can be adapted to different packaging standards, including but not limited to 2-inch, 4-inch, and 6-inch wafer packages, or custom-sized rectangular or circular devices. The micro-nano optical system can also be upgraded and redundant, and can be easily integrated with intelligent monitoring, optical power closed-loop feedback, and electronically controlled focusing systems.

[0036] The micro-nano optical system of this invention can be mass-produced based on standard microelectronics processing technology, suitable for mass production of wafers smaller than 12 inches, and compatible with CMOS-compatible material systems and process platforms. It can expand optical degrees of freedom using a multi-layer microstructure 12-stack configuration. The micro-nano optical system of this invention can be functionally expanded by combining laser frequency control, phase modulation modules, beamforming modules, and compressor modules to achieve advanced laser processing functions such as ultrafast laser pulse shaping, time multiplexing, spatial multiplexing, and wavelength multiplexing. It can be extended for applications in femtosecond laser etching, photoacoustic microscopy, laser-assisted deposition, micro-patterning interference exposure, and three-dimensional surface processing.

[0037] The micro-nano optical system provided by this invention achieves comprehensive optimization of processing accuracy, laser energy efficiency and equipment size in existing high-power laser optical solutions through the selection of high laser-resistant materials, large-area wafer-level fabrication, double-sided micro-nano structure configuration, integrated beam splitting and focusing design, scalable structural size and highly programmable output structure. It constructs an optical foundation platform for large-scale, highly consistent, high-throughput, and modular laser processing in the future.

[0038] Example 2: Refer to Figure 2 This invention discloses a micro / nano optical system for parallel processing with high-power lasers. The difference from Embodiment 1 is that the beam-splitting diffraction optical element 1 includes a substrate 11 and multiple microstructures 12 disposed on the substrate 11. The material of the beam-splitting diffraction optical element 1 possesses high optical transmittance, high thermal conductivity, high mechanical stability, and a high laser damage threshold. The microstructures 12 can withstand high-power laser irradiation, and their materials include, but are not limited to, one or more of diamond, SiC, AlN, Al2O3, MgO, CaF2, LiF, fused silica, optical ceramics, and composite crystals. The materials of the substrate 11 and the microstructures 12 can be the same or different; they can each be an independent single-layer structure, a multi-layer bonded structure, or a composite coating structure.

[0039] The thickness of substrate 11 is typically adjusted between 100 μm and 5 mm to accommodate different wavelengths (ultraviolet, visible, near-infrared, mid-infrared), different laser types (continuous, pulsed, ultrafast), and different application environments (high temperature, high humidity, vacuum, extreme cooling). The thickness of substrate 11 in this invention is designed and optimized based on a coupled model of maximum allowable optical path difference (OPD) and thermal diffusion length. The following thermal stability constraints must be met: ;in, The wavelength of the laser. For the thermal conductivity of beam-splitting diffraction optical element 1, As a safety factor, The average power of the laser. The absorption coefficient of beam-splitting diffraction optical element 1 is given. The temperature coefficient of refractive index. The refractive index of beam-splitting diffraction optical element 1 is... This refers to the coefficient of thermal expansion. For example, for high-power applications in the 1064nm band, 4H-SiC material is preferably used to fabricate the beam-splitting diffraction optical element 1, with a substrate 11 thickness of 300~500μm, so that the wavefront distortion of the beam-splitting diffraction optical element 1 does not exceed [the specified value]. .

[0040] Since laser beam splitting is achieved through the beam-splitting diffraction optical element 1, the microstructure 12 can be constructed using principles such as optical holography, phase mask calculation, multi-phase encoding, and multi-focus design. The microstructure 12 can take various forms, including continuous phase surfaces, stepped binary optical structures, super-diffraction gratings, and freeform surface microstructures 12. Furthermore, these microstructures 12 can be periodically or quasi-periodically arrayed on the substrate 11, or combined with asymmetric or gradient designs to achieve customized spot arrangements, thereby realizing functions such as equal-energy beam splitting, non-uniform power distribution, wavefront pre-adjustment before focusing, incident angle correction, dispersion control, and laser mode shaping. In this invention, the beam-splitting diffraction optical element 1 is constructed based on a stepped binary optical structure, and the height distribution of the microstructure 12 follows a phase-height mapping formula for the designed wavelength. and substrate 31 refractive index Arbitrary coordinates on the surface of beam-splitting diffraction optical element 1 The microstructure at height 12 satisfy, ;in, The coordinates of the distance between microstructure 12 and the center of beam-splitting diffraction optical element 1 are given. The wavelength of the laser. The refractive index of substrate 11 is... The total number of phase steps within 12 periods of the microstructure (e.g., using an 8th-order binary optical structure, then...) ), For quantization series.

[0041] To enable the beam-splitting diffraction optical element 1 to function as equal-energy beam splitting, non-uniform power distribution, and wavefront pre-tuning, the phase distribution of the beam-splitting diffraction optical element 1 is... Far-field amplitude of the target The interval is satisfied. ;in, For Fourier transform operators, The amplitude distribution of the incident laser beam. It is the imaginary unit. This invention is based on Fourier transform for characterization, employing an iterative Fourier transform algorithm or the GS algorithm in the phase space. With the target amplitude space The projection is iteratively projected between the beams to obtain the optimal phase distribution that satisfies the target beam splitting pattern, thereby achieving customized beam pattern arrangement.

[0042] Example 3: Reference Figure 3 This invention discloses a micro / nano optical system for high-power laser parallel processing. Unlike Embodiment 2, the metasurface lens array 3 includes a substrate 31 and multiple metasurface units 32 disposed on the substrate 31. Each metasurface unit 32 includes multiple nanopillars 33. Parallel laser focusing is achieved by the metasurface lens array 3. Each metasurface unit 32 has a one-to-one correspondence with a sub-beam formed by the beam splitting path of a diffractive optical element. The materials used include, but are not limited to, one or more of SiC, TiO2, Nb2O5, Ta2O5, Si3N4, ZnS, and diamond. The substrate 31 and nanopillars 33 can be made of the same or different materials; they can be independent single-layer structures, multi-layer bonded structures, or composite coating structures. Multiple nanopillars 33 can be arranged in a periodic or quasi-periodic array on the substrate 11, or they can be combined with asymmetric or gradient designs. Their structural morphology includes, but is not limited to, columnar, column-conical, fin-like, composite structures, and refractive + diffraction hybrid microstructures 12. Their processing technology includes, but is not limited to, electron beam lithography, nanoimprinting, focused ion beam, dry etching, atomic layer deposition, sputtering film formation and nanopattern transfer.

[0043] The metasurface lens array 3 can be designed with multi-band structures for different wavelengths (typically 355nm, 532nm, 1030nm, 1064nm, 1550nm, and 10.6μm) to achieve advanced wavefront control functions such as multi-point collimation and focusing, precise focal length control, high NA focusing (typical values ​​0.2–0.9), long / short focal length composite design, depth of focus extension, off-axis correction, polarization-sensitive focusing, vector beam shaping, vortex beam generation, and Bessel beam generation. The metasurface unit 32 of this invention uses transmission phase control to focus the parallel beam to the focal length. Phase distribution on the lens unit at that location The hyperboloid phase formula must be satisfied. ;in, The wavelength of the laser. Focal length , The coordinates of the distance between the nanopillar 33 and the center of the metasurface unit 32 are given.

[0044] Meanwhile, the metasurface unit 32 also achieves the aforementioned phase distribution by establishing a diameter-phase mapping database for the nanopillars 33. That is, the etching height on the surface of substrate 31 is Nanopillars 33, by changing the diameter of nanopillars 33 Adjusting the equivalent refractive index Thus covering Phase requirements, ;in, The wavelength of the laser. For equivalent refractive index, the diameter of the nanopillar is 33. =0~500nm, nanopillar height 33 =1μm.

[0045] To achieve highly consistent parallel processing, the metasurface lens array 3 employs an improved GS algorithm in its structural design. This algorithm introduces a dedicated evaluation function for high-power processing, focusing not only on diffraction efficiency but also strictly constraining the uniformity of each sub-beam. The evaluation function for the metasurface lens array 3... for, ;in, For diffraction efficiency, and As the weighting coefficient, set > , For the root mean square error of the energy of all sub-beams, priority is given to ensuring the consistency of the beam energy (target non-uniformity). This prevents individual light spots from being too strong, causing material ablation, or too weak, causing processing failure.

[0046] Example 4: This invention discloses a micro / nano optical system for parallel processing of high-power lasers. The difference from Example 3 is that the optimization target, namely the beam-splitting optical path and laser beam energy distribution, is input into the simulation software. The aforementioned structural model is established, and the software's optimization algorithm, combined with the range of fabricable structures, is used to optimize the structural morphology of the beam-splitting diffraction optical element 1 and the metasurface lens array 3. The basic idea is to change the structural morphology, calculate the difference between the result and the input target, and the diffraction efficiency, finding the solution with the smallest difference from the target as the final design result. Electron beam lithography, electron beam evaporation coating, plasma etching, and nanoimprinting processes are used to fabricate the beam-splitting diffraction optical element 1 and the metasurface lens array 3, assembling them to obtain the micro / nano optical structure of this invention.

[0047] Specifically, for high-power applications in the 1064nm band, refer to... Figure 4 The beam-splitting diffraction optical element 1 adopts an 8th-order binary optical structure and is preferably fabricated from 4H-SiC material. The substrate 11 has a thickness of 500 μm, the microstructure 12 has a height of 100 nm and a minimum resolution of 3 μm, and the single device size is 1 x 1 cm. It achieves beam splitting effects of 1 to 4, 1 to 9, and 1 to 26, respectively, corresponding to a point arrangement with a spacing of 1.5 cm at 0.5 meters. This corresponds to the arrangement of the metasurface units 32 in the metasurface lens array 3. Figure 5 The device was fabricated using a multi-round contact photolithography overlay and plasma dry etching process.

[0048] Reference Figure 4 The metasurface lens array 3 was simulated and calculated using the finite element simulation software COMSOL, with reference to... Figure 6 Each metasurface unit 32 consists of multiple nanopillars 33 arranged in a two-dimensional periodic array, with a height of 1 μm, a period of 600 nm, and a diameter that gradually varies from 0 to 500 nm, thereby achieving focusing performance with a numerical aperture of 0.5 and a focal length of 1 cm. (Refer to...) Figure 7 Each metasurface unit 32 is fabricated using a step-by-step nanoimprinting process to create a device array template. It is preferably made of 4H-SiC material. The mass production of metasurface lens arrays 3 is achieved through nanoimprinting and dry etching processes. 26 identical metalenses are arranged in a single 4H-SiC wafer. The on-chip fabrication 3-singma error is less than 20nm and the focal length error is less than 15μm, achieving excellent on-chip device consistency.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A micro / nano optical system for high-power laser parallel processing, characterized in that: The system includes sequentially arranged beam-splitting diffraction optical elements, a convex lens, and a metasurface lens array. The beam-splitting diffraction optical elements are composed of wide-bandgap semiconductor materials and / or high-melting-point inorganic non-metallic materials. Multiple microstructures on the beam-splitting diffraction optical elements are arranged relative to the laser source and split the laser beam into multiple sub-beams, which are then emitted onto the convex lens. The metasurface lens array is composed of wide-bandgap semiconductor materials and / or high-refractive-index inorganic non-metallic materials. Multiple metasurface units on the metasurface lens array are arranged in a one-to-one correspondence with the multiple sub-beams emitted from the convex lens and focus the multiple sub-beams onto the workpiece. The substrate thickness L of the beam-splitting diffraction optical element satisfies the following condition: ;in, The wavelength of the laser. For the thermal conductivity of beam-splitting diffraction optical elements, As a safety factor, The average power of the laser. The absorption coefficient of a beam-splitting diffraction optical element. The temperature coefficient of refractive index. The refractive index of a beam-splitting diffraction optical element. is the coefficient of thermal expansion.

2. The micro / nano optical system for high-power laser parallel processing according to claim 1, characterized in that: The beam-splitting diffraction optical element is composed of one or more of the following: diamond, SiC, AlN, Al2O3, MgO, CaF2, LiF, fused silica, optical ceramics, and composite crystals.

3. A micro / nano optical system for high-power laser parallel processing according to claim 2, characterized in that: The substrate material of the beam-splitting diffraction optical element is 4H-SiC with a thickness of 300~500μm, so that the wavefront distortion of the beam-splitting diffraction optical element does not exceed .

4. A micro / nano optical system for high-power laser parallel processing according to claim 1, characterized in that: The microstructure height of the beam-splitting diffraction optical element satisfy, ;in, The coordinates of the distance between the microstructure and the center of the beam-splitting diffraction optical element are... The wavelength of the laser. The refractive index of the substrate is... This represents the total number of phase steps within the microstructure period. For quantization series.

5. A micro / nano optical system for high-power laser parallel processing according to claim 1, characterized in that: Phase distribution of the beam-splitting diffraction optical element Far-field amplitude of the target The interval is satisfied. ;in, For Fourier transform operators, The amplitude distribution of the incident laser beam. It is the imaginary unit.

6. A micro / nano optical system for high-power laser parallel processing according to claim 1, characterized in that: The metasurface lens array is made of one or more of the following materials: SiC, TiO2, Nb2O5, Ta2O5, Si3N4, ZnS, and diamond.

7. A micro / nano optical system for high-power laser parallel processing according to claim 1, characterized in that: Phase distribution of the metasurface unit satisfy, ;in, The wavelength of the laser. Focal length , The coordinates are the distance between the nanopillar and the center of the metasurface unit.

8. A micro / nano optical system for high-power laser parallel processing according to claim 7, characterized in that: The metasurface unit achieves phase distribution by establishing a nanopillar diameter-phase mapping database. Phase mapping model satisfy, ;in, The wavelength of the laser. For equivalent refractive index, the diameter of the nanopillar is... =0~500nm, nanopillar height =1μm.

9. A micro / nano optical system for high-power laser parallel processing according to claim 1, characterized in that: Evaluation function of the metasurface lens array for, ;in, For diffraction efficiency, and As the weighting coefficient, set > , denoted as the root mean square error of the energy of all sub-beams.

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