A modification processing method and processing system based on beam shaping

Abstract

The present invention provides a modification processing method and processing system based on beam shaping, comprising the following steps: based on a three-dimensional model of the target modified structure, obtaining a three-dimensional light field distribution corresponding to the three-dimensional model through a holographic algorithm, and generating a phase modulation diagram; loading the phase modulation diagram through a spatial light modulator to modulate the wavefront phase of the incident laser, so that the light beam is focused into a preset spatial curved surface light field on the surface or inside the material; utilizing the spatial curved surface light field to focus on the material, causing the material within the light field region to undergo nonlinear absorption or phase change, directly forming a modified structure of the three-dimensional model. This invention overcomes the limitations of traditional point-by-point scanning processing, significantly improving the processing efficiency and flexibility of complex three-dimensional structures. It is suitable for scenarios such as internal waveguide writing in transparent materials, curved crack separation, large-area peeling, functionalized surface preparation, and large-scale removal of opaque materials, significantly improving processing efficiency and quality.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to a modification processing method and processing system based on beam shaping. Background Art

[0002] Laser processing technology, due to its advantages such as high precision, non-contact operation, and wide range of applicable materials, is widely used in micro-nano manufacturing, optical device processing, semiconductors, and other fields. However, as industrial demands evolve towards complex three-dimensional structures, high efficiency, and high consistency, the limitations of traditional laser processing technology are becoming increasingly prominent.

[0003] Traditional laser processing often uses a Gaussian beam or fixed focal depth focusing method, with the focal position relying on mechanically moving optical elements (such as an objective lens or sample stage) for adjustment. This model suffers from low efficiency, limited precision, and insufficient flexibility. Existing focus control technologies primarily rely on solutions such as acousto-optic modulators (AOMs), galvanometer scanning, or adjustable lenses, but these have significant drawbacks. For example, while the AOM solution can achieve nanosecond focus switching, it has low modulation freedom and only supports one-dimensional or simple two-dimensional path adjustment, making it difficult to generate complex three-dimensional focus distributions. Galvanometer scanning systems rely on high-speed mirror deflection, and the focus movement range is limited by the optical design. High-speed motion is also prone to thermal drift and mechanical wear. Adjustable lenses (such as liquid crystal lenses) have slow response speeds (milliseconds), making it difficult to meet the requirements of high-repetition-rate processing, and the focus depth control range is limited.

[0004] To improve processing efficiency, some technologies attempt to generate static multifocal patterns using diffractive optical elements (DOEs) or lens arrays. However, these solutions suffer from poor uniformity, lack of flexibility, and difficulty in three-dimensional expansion. The processing of complex three-dimensional structures also presents numerous challenges, such as generating longitudinally modified surfaces, controlling curved cracks, and fabricating waveguides.

[0005] Although spatial light modulators (SLMs) have been used for phase modulation, their applications in laser processing are still limited to simple two-dimensional pattern generation or static holographic projection, failing to fully realize their flexible control potential.

[0006] In summary, existing laser processing technology has significant shortcomings in terms of control flexibility, three-dimensional structure processing efficiency and complex light field generation capabilities. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention provides a modification processing method and system based on beam shaping. This method uses light field manipulation technology to shape the laser focal plane into a predefined spatial light field (e.g., complex curves or surfaces). This light field is then used to perform a "one-step" spatial modification of the material. Alternatively, dynamic scanning-based spatial modification, based on curved surfaces, can be performed over time. This method overcomes the limitations of traditional point-by-point scanning processing, significantly improving the processing efficiency and flexibility of complex three-dimensional structures. It is suitable for applications such as internal waveguide inscription in transparent materials, separation of curved cracks, large-area peeling, functionalized surface preparation, and large-scale removal of opaque materials.

[0008] The present invention achieves the above technical objectives through the following technical means.

[0009] A modification processing method based on beam shaping includes the following steps:

[0010] According to the three-dimensional model of the target modified structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm to generate a phase modulation map;

[0011] The phase modulation pattern is loaded through a spatial light modulator to modulate the wavefront phase of the incident laser so that the light beam is focused into a preset spatial curved surface light field on the surface or inside the material;

[0012] The spatial curved surface light field is focused on the material to cause nonlinear absorption or phase change in the material within the light field area, thereby directly forming a modified structure of a three-dimensional model.

[0013] Furthermore, the spatial curved surface light field is a static light field, which statically modulates the wavefront phase of the incident laser so that the light beam is focused on the surface or inside of the material into a preset spatial curved surface light field; the spatial curved surface light field is used to perform one-step spatial modification on the material to be processed to directly form the structure of a three-dimensional model; the static modulation reversely determines the phase distribution based on an iterative algorithm.

[0014] Furthermore, the spatial curved surface light field is a dynamic light field, which dynamically modulates the wavefront phase of the incident laser so that the light beam is focused on the surface or inside of the material into a preset spatial curved surface light field; the spatial curved surface light field is used to perform dynamic scanning spatial modification on the material to be processed "with the surface as the unit", directly forming the structure of a three-dimensional model.

[0015] Furthermore, the light beam is focused into a preset spatial curved light field on the surface or inside of the material through dynamic modulation, which specifically includes the following steps:

[0016] Inverse determination of phase distribution based on iterative algorithm ;

[0017] The phase diagram of the changing focus position is generated according to the dynamic movement of the focus position, specifically:

[0018] The processing path is obtained according to the three-dimensional model, and the processing path is divided into N processing points according to the spatial height. ;

[0019] The spatial coordinates of the jth processing point ,in is the distance from the jth processing point to the last lens plane of the 4f system, then the phase diagram of the jth processing point loaded on the SLM is:

[0020]

[0021] Will Overlay The phase diagram of the jth processing point after superposition is obtained =mod[ + ]2 , where mod[] represents the + 2 the remainder of the quotient of

[0022] Obtain the set of phase images after superposition of N processing points, recorded as ;

[0023] Will The phase images of the processing points are sequentially loaded into the SLM at dynamic time intervals to form a dynamic spatial curved light field.

[0024] Furthermore, the phase distribution corresponding to each slice is reversely deduced based on an iterative algorithm, which specifically includes the following steps:

[0025] The target 3D model is sliced ​​into K planes at equal intervals along the optical axis, with a slice spacing of Δl; is the distance between the kth section and the SLM; the light intensity of the kth section is ; Set random phase =rand(x,y)×2π, where rand(x,y) represents generating a random number with the range [0,1] at (x,y), (x,y) represents the pixel position, and x∈[ ],y∈[ ]; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; initial light field , i is an imaginary number;

[0026] The light fields of K planes are obtained according to the forward propagation along the optical axis. Specifically, the forward propagation is as follows: the light field propagated from the k-1th plane to the kth plane is updated according to the following expression:

[0027]

[0028] in, is the two-dimensional inverse fast Fourier transform, FFT2 is the two-dimensional fast Fourier transform, is the transmission function, , where is the number of peaks in the x direction per unit length, is the number of peaks in the x direction per unit length, , where m and n are frequency indices corresponding to discrete positions in the frequency domain, m∈[ ]; n∈[ ]; is the laser wavelength;

[0029] Starting from the K plane in the opposite direction of the optical axis, according to the reverse replacement and propagation, the light field amplitude is replaced with the target light intensity in sequence, and the phase is retained. Specifically:

[0030] Target light intensity at K plane Expressed as: ;in Phase angle function for extracting complex numbers;

[0031] The light intensity propagated from the kth plane to the k-1th plane according to the reverse propagation along the opposite direction of the optical axis is updated according to the following expression:

[0032]

[0033] After backpropagation to the SLM plane, the phase is updated:

[0034]

[0035] in, Represents the target light intensity at the SLM plane.

[0036] Furthermore, the slice spacing Δl satisfies the following conditions:

[0037]

[0038]

[0039] in: is the laser wavelength; NA is the system numerical aperture, dimensionless; Δx, Δy are the SLM pixel sizes; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; and f is the focal length.

[0040] Furthermore, the focal plane shape of the spatial curved surface light field is one or a combination of two or more of a plane, an inclined plane, and a curved surface; the spatial curved surface light field includes one or a combination of two or more of a plane light field, a curved surface light field, a curve light field, and a discrete point matrix light field.

[0041] A processing system for a modified processing method based on beam shaping includes a laser system for generating the laser beam required for processing; a spatial light modulator for loading a phase modulation pattern and regulating the laser wavefront phase; an optical transmission module for beam shaping and focusing; a real-time monitoring module for visual feedback of the processing process; and a computer control system for phase pattern generation, SLM dynamic control, and motion coordination of an XYZ translation stage.

[0042] The beneficial effects of the present invention are:

[0043] 1. The beam shaping-based modification method described in this invention utilizes a spatially curved surface light field to perform a "one-step" spatial modification of materials. It also allows for dynamic, time-varying, surface-based spatial modification. This method overcomes the limitations of traditional point-by-point scanning processing, significantly improving the processing efficiency and flexibility of complex three-dimensional structures. It is suitable for applications such as internal waveguide writing in transparent materials, curved surface crack separation, large-area peeling, and functionalized surface preparation.

[0044] 2. The beam shaping-based processing method described in this invention utilizes SLM phase modulation to directly control the three-dimensional coordinates of the focal point, avoiding inertial errors and vibrations introduced by mechanical motion. It enables precise reproduction of complex geometries and supports the generation of focal planes for any preset curve, curved surface, or inclined surface. The processing path exhibits minimal deviation from the designed model, making it particularly suitable for high-fidelity manufacturing of optical components such as Fresnel lenses and freeform surfaces.

[0045] 3. The beam shaping-based modification method described in this invention offers dynamic mode flexibility for continuous processing and, through real-time phase image switching, enables spatial focal plane movement along a three-dimensional trajectory (e.g., spiral drilling, special-shaped cutting), making it suitable for machining complex components. The static mode efficiently covers a large area, generating a spatial light field. A single exposure allows for surface functionalization of the beam's focal area (e.g., superhydrophobic micro-nanostructuring), resulting in highly consistent processing.

[0046] 4. The beam shaping-based modification method described in this invention leverages nonlinear absorption effects to achieve non-destructive modification within transparent materials such as glass, sapphire, and crystals, overcoming the limitations of traditional surface processing techniques. By longitudinally penetrating the modified surface to induce clean cracking, this method is suitable for curved surface separation of brittle materials such as sapphire and silicon wafers, achieving low edge roughness and high yield. Polymer and thin film processing: The low-energy static multi-focus mode of this invention enables microstructuring of flexible materials such as PI films and PDMS, avoiding thermal damage.

[0047] 5. The beam shaping-based processing method described in this invention, through spatial curved surface light field control technology, expands the dimensionality of laser processing from two-dimensional planes to three-dimensional space. This achieves a quantum leap in efficiency, precision, flexibility, and applicability, providing a new solution for high-value-added precision manufacturing and possessing significant industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, it is obvious that other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 Schematic diagram of the beam shaping-based modification and processing system according to the present invention.

[0050] Figure 2 Schematic diagram of processing a three-dimensional optical device using the beam shaping-based modification processing method described in the present invention.

[0051] Figure 3 Part of the focal plane and three-dimensional structure shape.

[0052] Figure 4 Schematic diagram of processing curved surface cracks using the beam shaping-based modification processing method described in the present invention.

[0053] Figure 5 This is a schematic diagram of processing a two-dimensional group of holes using the dynamic and static combined modification processing method based on beam shaping described in the present invention.

[0054] In the picture:

[0055] 1-Laser system, 2-Beam expander, 3-Attenuator, 4-Mirror, 5-Spatial light modulator, 6-Convex lens, 7-Beam splitter, 8-White light source, 9-CCD, 10-Dichroic mirror, 11-Processing sample, 12-XYZ translation stage, 13-Computer control system. DETAILED DESCRIPTION

[0056] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "axial", "radial", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0058] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0059] like Figure 2 As shown, the modification processing method based on beam shaping of the present invention includes the following steps:

[0060] According to the three-dimensional model of the target modified structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm to generate a phase modulation map;

[0061] The phase modulation pattern is loaded through a spatial light modulator to modulate the wavefront phase of the incident laser so that the light beam is focused into a preset spatial curved surface light field on the surface or inside the material;

[0062] The spatial curved light field is focused on the material to cause nonlinear absorption or phase change in the material within the light field area, directly forming a modified structure of a three-dimensional model without the need for point-by-point scanning of the focus of traditional laser modification to achieve modification processing.

[0063] The present invention can modulate the wavefront phase of the incident laser by static modulation or dynamic modulation:

[0064] When the wavefront phase of the incident laser is statically modulated, the light beam is focused into a preset spatial curved light field on the surface or inside the material; the spatial curved light field is used to perform one-step spatial modification of the material to be processed, directly forming the structure of a three-dimensional model; the static modulation reversely determines the phase distribution based on an iterative algorithm.

[0065] When the wavefront phase of the incident laser is dynamically modulated, the light beam is focused into a preset spatial curved light field on the surface or inside the material; the spatial curved light field is used to perform dynamic scanning spatial modification on the material to be processed "with the surface as the unit", directly forming the structure of a three-dimensional model.

[0066] Example 1

[0067] The modification and processing method based on beam shaping described in Example 1 includes the following steps:

[0068] According to the three-dimensional model of the target modified structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm to generate a phase modulation map;

[0069] The phase modulation pattern is loaded through a spatial light modulator (SLM) to statically modulate the wavefront phase of the incident laser so that the light beam is focused into a preset spatial curved light field on the surface or inside the material; the static modulation reversely determines the phase distribution based on an iterative algorithm.

[0070] The spatial curved surface light field is used to perform one-step spatial modification on the material to be processed, thereby directly forming a three-dimensional model structure;

[0071] Feedback control of the machining process is carried out through a real-time monitoring system to ensure machining accuracy and consistency.

[0072] The phase distribution corresponding to each slice is reversely deduced based on the iterative algorithm, which specifically includes the following steps:

[0073] The target 3D model is sliced ​​into K planes at equal intervals along the optical axis, with a slice spacing of Δl. The slice spacing Δl satisfies the following conditions:

[0074]

[0075]

[0076] in: is the laser wavelength (unit: nm); NA is the system numerical aperture, dimensionless; Δx, Δy are the SLM pixel sizes (unit: micrometer); Nx is the number of pixels in the x direction, dimensionless; Ny is the number of pixels in the y direction, dimensionless; f is the focal length (unit: mm).

[0077] is the distance between the kth section and the SLM; the light intensity of the kth section is ; Set random phase =rand(x,y)×2π, where rand(x,y) represents generating a random number with the range [0,1] at (x,y), (x,y) represents the pixel position, and x∈[ ],y∈[ ]; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; initial light field , i is an imaginary number;

[0078] The light fields of K planes are obtained according to the forward propagation along the optical axis. Specifically, the forward propagation is as follows: the light field propagated from the k-1th plane to the kth plane is updated according to the following expression:

[0079]

[0080] in, is the two-dimensional inverse fast Fourier transform, FFT2 is the two-dimensional fast Fourier transform, is the transmission function, , where is the number of peaks in the x direction per unit length, is the number of peaks in the x direction per unit length, , where m and n are frequency indices corresponding to discrete positions in the frequency domain, m∈[ ]; n∈[ ]; is the laser wavelength;

[0081] Starting from the K plane in the opposite direction of the optical axis, according to the reverse replacement and propagation, the light field amplitude is replaced with the target light intensity in sequence, and the phase is retained. Specifically:

[0082] Target light intensity at K plane Expressed as: ;in Phase angle function for extracting complex numbers;

[0083] The light intensity propagated from the kth plane to the k-1th plane according to the reverse propagation along the opposite direction of the optical axis is updated according to the following expression:

[0084]

[0085] After backpropagation to the SLM plane, the phase is updated:

[0086]

[0087] in, Represents the target light intensity at the SLM plane.

[0088] Examples

[0089] Processed three-dimensional structures such as Figure 2 As shown in middle a, the three-dimensional structure is similar to a V-shaped three-dimensional structure;

[0090] like Figure 2 As shown in b, the plane slices in the Z direction, the pixel size of each slice is 1272*1024, the number of slices is determined by the distance between adjacent slices, and the slice distance is (Unit: mm), and there are:

[0091]

[0092]

[0093] The number of pixels of the SLM is 1272*1024, the pixel size is 12.5 microns, the focal length is 300mm, and the laser wavelength is 1064nm. The numerical aperture NA of the system is 0.0335, so we have , because the processing is precision processing, the higher the resolution, the better, so choose The three-dimensional structure processed in the embodiment has a thickness of 1 mm. Then the number of plane slices is 1mm / 0.02mm=50, and the interval between adjacent slices is 0.02mm.

[0094] The optical axis (z direction) is divided into 50 planes, and the distance between the kth section and the SLM is ;like Figure 2 The light intensity distribution slice diagram shown in c in the figure, the light intensity of the kth section is ; Process the slices so that the solid part of the slice takes the light intensity value of 1 (corresponding to black in the grayscale image) and the empty part takes the light intensity value of 0 (corresponding to white in the grayscale image) to obtain the three-dimensional light intensity distribution slice of the spatial light. Set the random phase =rand(x,y)×2π, where (x,y) represents the pixel position, x∈[ ] That is, x is at (-636, 635), y∈[ ] That is, y is at (-512, 511); the initial light field .

[0095] The light fields of K planes are obtained according to the forward propagation along the optical axis. Specifically, the forward propagation is as follows: the light field propagated from the k-1th plane to the kth plane is updated according to the following expression:

[0096]

[0097] in, is the two-dimensional inverse fast Fourier transform, FFT2 is the two-dimensional fast Fourier transform, is the transmission function, , where is the number of peaks in the x direction per unit length, is the number of peaks in the x direction per unit length, , where m and n are frequency indices corresponding to discrete positions in the frequency domain, m∈[ ]; n∈[ ]; is the laser wavelength;

[0098] Starting from the K plane in the opposite direction of the optical axis, according to the reverse replacement and propagation, the light field amplitude is replaced with the target light intensity in sequence, and the phase is retained. Specifically:

[0099] Target light intensity at K plane Expressed as: ;in Phase angle function for extracting complex numbers;

[0100] Back propagation to the previous plane, that is, from back to front ( ) Backward propagation; the light intensity propagated from the kth plane to the k-1th plane according to the back propagation in the opposite direction of the optical axis is updated according to the following expression:

[0101]

[0102] After backpropagation to the SLM plane, the phase is updated:

[0103]

[0104] in, Represents the target light intensity at the SLM plane.

[0105] Convergence judgment: Repeat forward propagation and backward propagation to replace Iterate until the error When the value is less than the threshold (the threshold is 0.001) or the maximum number of iterations is reached, the target phase map is finally obtained.

[0106] Use as Figure 1 The optical system shown here uses a picosecond laser system generating a laser with a wavelength of 1064 nm, a pulse width of 10 ps, ​​a repetition rate of 100 kHz, and an average power of 15 W. This laser is guaranteed to completely cover the SLM panel. The sample being processed is 5 mm thick and measures 5 mm x 5 mm x 5 mm. The sample is made of transparent acrylic, polished on all sides, and is used to fabricate optical devices.

[0107] Place the sample on the platform and irradiate it with light for 0.5s. The irradiation time is determined by the sample material and the laser. Figure 2 In addition to the V-groove optical devices in this case, this method can also be used to process Figure 3 Various three-dimensional spatial structures or waveguide structures shown.

[0108] Example 2

[0109] The modification and processing method based on beam shaping described in Example 2 includes the following steps:

[0110] According to the three-dimensional model of the target modified structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm to generate a phase modulation map;

[0111] The phase modulation pattern is loaded through a spatial light modulator to dynamically modulate the wavefront phase of the incident laser so that the light beam is focused into a preset spatial curved light field on the surface or inside the material;

[0112] The spatial curved surface light field is used to perform dynamic scanning spatial modification on the material to be processed "with the surface as the unit", so as to directly form the structure of a three-dimensional model.

[0113] The light beam is focused on the surface or inside of the material into a preset spatial curved light field through dynamic modulation, which specifically includes the following steps:

[0114] Inverse determination of phase distribution based on iterative algorithm , which is the same as static modulation;

[0115] The phase diagram of the changing focus position is generated according to the dynamic movement of the focus position, specifically:

[0116] The processing path is obtained according to the three-dimensional model, and the processing path is divided into N processing points according to the spatial height. ;

[0117] The spatial coordinates of the jth processing point ,in is the distance from the jth processing point to the last lens plane of the 4f system, then the phase diagram of the jth processing point loaded on the SLM is:

[0118]

[0119] Will Overlay The phase diagram of the jth processing point after superposition is obtained =mod[ + ]2 , where mod[] represents the + 2 the remainder of the quotient of

[0120] Obtain the set of phase images after superposition of N processing points, recorded as ;

[0121] Will The phase images of the processing points are sequentially loaded into the SLM at dynamic time intervals to form a dynamic spatial curved light field.

[0122] Examples

[0123] Inverse determination of phase distribution based on iterative algorithm , The generation method is the same as that of static modulation. Please refer to the static modulation part in Example 1 to generate Figure 4 The spatial structure shown in a.

[0124] According to the three-dimensional model, we need to cut the processing path. Figure 4 The quartz plate shown is 1*10*30mm in size and needs to be cut to a length of 10mm. The sample is placed at the spatial coordinates (0, 0, 300). The processing path is from (5, 0, 300) to (-5, 0, 300), and the processing path is a straight line. If the dynamic space interval is set to 0.05mm, 200 processing points are required for a 10mm spacing. According to the processing path, the processing points are (5, 0, 300)-(4.95, 0, 300)-(4.9, 0, 300)-(4.85, 0, 300)-...(0.05, 0, 300)-(0, 0, 300)-(-0.05, 0, 300)...(-4.9, 0, 300)-(-4.95, 0, 300)-(-5, 0, 300).

[0125] Let the spatial coordinates of the jth processing point be ,in is the distance from the jth processing point to the last lens plane of the 4f system, then the phase diagram of the jth processing point loaded on the SLM is:

[0126]

[0127] Will Overlay The phase diagram of the jth processing point after superposition is obtained =mod[ + ]2 , where mod[] represents the + 2 the remainder of the quotient of

[0128] Obtain the set of phase images after superposition of N processing points, recorded as ;

[0129] Will The phase image of the processing point is loaded into the SLM in sequence at dynamic time intervals of 0.1s to form a dynamic spatial curved light field.

[0130] Use as Figure 1 The optical system shown in the figure is a picosecond laser system that generates a laser with a wavelength of 1064 nm, a pulse width of 10 ps, ​​an average power of 30 W, and a repetition rate of 100 kHz. Load them onto the SLM in sequence, set the laser power to 30W, and follow Figure 4 Processing is performed as shown in b.

[0131] Get as Figure 4 The surface cutting effect shown in c.

[0132] Example 3:

[0133] The modification and processing method based on beam shaping described in Example 3 includes the following steps:

[0134] S01: Based on the three-dimensional model of the target modified structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm, and a phase modulation diagram is generated. The phase distribution is reversely determined based on the iterative algorithm. , The generation method is the same as that of static modulation. Please refer to the static modulation part in Example 1 to generate Figure 5 The spatial structure shown in a;

[0135] S02: Use Figure 1The optical system shown in the figure is a picosecond laser system that generates a laser with a wavelength of 1064 nm, a pulse width of 10 ps, ​​a repetition rate of 100 kHz, and a laser power of 15 W. The processed sample is organic glass with a size of 3 mm*9 mm*1 mm. The coordinates of its center point are (0, 0, 300), and the unit is mm. The coordinate positions that need dynamic displacement processing are (-4, 1, 300), (-3, 1, 300), (-2, 1, 300), (-1, 1, 300), (0, 1, 300), (1, 1, 300), (2, 1, 300), (3, 1, 300), (4, 1, 300), (-4, 0, 300), (-3, 0, 300), (-2, 0, 300), (-1, 0, 300), (0, 0, 300), (1, 0, 300), (2, 0, 300), (3, 0, 300), (4, 0, 300), (-4, -1, 300), (-3, -1, 300), (-2, -1, 300), (-1, -1, 300), (0, -1, 300), (1, -1, 300), (2, -1, 300), (3, -1, 300), (4, -1, 300). Dynamically moving the focus position according to the method of Example 2 obtains a set of phase maps, such as Figure 5 As shown in b, 27 processing points are obtained, which are recorded as 1, 2, ..., 27 according to the order of the coordinate points above; the set of superimposed phase maps is recorded as .

[0136] S03: Each coordinate position requires laser irradiation for 1 second. This 1 second period is static processing. Then, static modulation and dynamic modulation are switched alternately to avoid material damage caused by stress and heat concentration. The switching order of processing at this time is as follows:

[0137] 1. If the number of a row of the array being processed is an odd number m', the phase diagram is switched in the order of 1, 3, 5, ..., m', 2, 4, 6, ..., m'-2. When the previous row is processed, the next row is processed in sequence.

[0138] 2. If the number of a row of the array being processed is an even number n', the phase diagram is switched in the order of 1, 3, 5, ..., n'-1, 2, 4, 6, ..., n'. When the previous row is processed, the next row is processed in sequence.

[0139] S04: According to the rules of step S03, the position is dynamically switched. The switching time of each phase diagram is 1s, and the phase diagram switching order is 1, 3, 5, 7, 9, 2, 4, 6, 8, 10, 12, 14, 16, 18, 11, 13, 15, 17, 19, 21, 23, 25, 27, 20, 22, 24, 26. Static irradiation is performed for 1s at each coordinate position, and then dynamic switching is performed in the above order. In this way, the dynamic and static combination processing is completed, and the following is obtained: Figure 5 The finished product shown in c.

[0140] In addition, the modification processing method based on beam shaping described in the present invention can be used for spatial curved surface modification for brittle material peeling processing parallel to the surface, for brittle material splitting processing vertical to the surface, and can also be used with the aid of chemical etching methods for internal spatial microchannel processing of brittle materials, and can also be used for high-efficiency material removal processing of non-transparent materials.

[0141] like Figure 1 As shown, the surface modification processing system based on beam shaping described in the present invention includes a laser system 1, a spatial light modulator 5, an optical transmission module, a real-time monitoring module and a computer control system 13; the laser system 1 is used to generate the laser beam required for processing; the spatial light modulator 5 is used to load the phase modulation diagram and adjust the laser wavefront phase; the optical transmission module includes a beam expander 2, an attenuation plate 3, a reflector 4, a beam splitter 7, an objective lens 11 and a convex lens 6, which are used for beam shaping and focusing; the real-time monitoring module includes a CCD 9 and a dichroic mirror 10, which are used for visual feedback of the processing process; the computer control system 13 is used for phase diagram generation, SLM dynamic control and motion coordination of the XYZ translation stage 12.

[0142] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0143] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A modification processing method based on beam shaping, characterized in that: The steps include: According to the three-dimensional model of the target modified structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm to generate a phase modulation map; The phase modulation pattern is loaded through a spatial light modulator to modulate the wavefront phase of the incident laser so that the light beam is focused on the surface or inside the material into a preset spatial curved surface light field; the spatial curved surface light field is a dynamic light field or a static light field; When the spatial curved surface light field is a dynamic light field, the wavefront phase of the incident laser is dynamically modulated so that the light beam is focused on the surface or inside of the material into a preset spatial curved surface light field; the spatial curved surface light field is used to perform dynamic scanning spatial modification on the material to be processed "with the surface as the unit" to directly form a three-dimensional model structure; wherein the dynamic modulation is used to focus the light beam on the surface or inside of the material into the preset spatial curved surface light field, specifically comprising the following steps: Inverse determination of phase distribution based on iterative algorithm ; The phase diagram of the changing focus position is generated according to the dynamic movement of the focus position, specifically: The processing path is obtained according to the three-dimensional model, and the processing path is divided into N processing points according to the spatial height. ; Let the spatial coordinates of the jth processing point be ,in is the distance from the jth processing point to the last lens plane of the 4f system, then the phase diagram of the jth processing point loaded on the SLM is: ； Will Overlay The phase diagram of the jth processing point after superposition is obtained =mod[ + ]2 , where mod[] represents the + 2 the remainder of the quotient of Obtain the set of phase images after superposition of N processing points, recorded as ; Will The phase image of the processing point is loaded into the SLM in sequence at dynamic time intervals to form a dynamic spatial curved surface light field; The spatial curved surface light field is focused on the material to cause nonlinear absorption or phase change in the material within the light field area, thereby directly forming a modified structure of a three-dimensional model.

2. The modification method based on beam shaping according to claim 1, characterized in that: The spatial curved surface light field is a static light field, which statically modulates the wavefront phase of the incident laser so that the light beam is focused on the surface or inside the material into a preset spatial curved surface light field; the spatial curved surface light field is used to perform one-step spatial modification of the material to be processed to directly form the structure of a three-dimensional model; the static modulation reversely determines the phase distribution based on an iterative algorithm.

3. The modification method based on beam shaping according to claim 1 or 2, characterized in that: The phase distribution corresponding to each slice is reversely deduced based on the iterative algorithm, which specifically includes the following steps: The target 3D model is sliced ​​into K planes at equal intervals along the optical axis, with a slice spacing of Δl; is the distance between the kth section and the SLM; the light intensity of the kth section is ; Set random phase =rand(x,y)×2π, where rand(x,y) represents generating a random number with the range [0,1] at (x,y), (x,y) represents the pixel position, and x∈[ ],y∈[ ]; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; initial light field , i is an imaginary number; The light fields of K planes are obtained according to the forward propagation along the optical axis. Specifically, the forward propagation is as follows: the light field propagated from the k-1th plane to the kth plane is updated according to the following expression: ； in, is the two-dimensional inverse fast Fourier transform, FFT2 is the two-dimensional fast Fourier transform, is the transmission function, , where is the number of peaks in the x direction per unit length, is the number of peaks in the x direction per unit length, , where m and n are frequency indices corresponding to discrete positions in the frequency domain, m∈[ ]; n∈[ ]; is the laser wavelength; Δx, Δy are the SLM pixel sizes; Starting from the K plane in the opposite direction of the optical axis, according to the reverse replacement and propagation, the light field amplitude is replaced with the target light intensity in sequence, and the phase is retained. Specifically: Target light intensity at K plane Expressed as: ;in Phase angle function for extracting complex numbers; The light intensity propagated from the kth plane to the k-1th plane according to the reverse propagation along the opposite direction of the optical axis is updated according to the following expression: ； After backpropagation to the SLM plane, the phase is updated: ； in, Represents the target light intensity at the SLM plane.

4. The modification method based on beam shaping according to claim 3, characterized in that: The slice spacing Δl satisfies the following conditions: ； ； in: is the laser wavelength; NA is the system numerical aperture, dimensionless; Δx, Δy are the SLM pixel sizes; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; and f is the focal length.

5. The modification method based on beam shaping according to claim 1, characterized in that: The focal plane shape of the spatial curved surface light field is one of a plane, an inclined surface, and a curved surface, or a combination of two or more thereof; the spatial curved surface light field includes one of a plane light field, a curved surface light field, a curve light field, and a discrete dot matrix light field, or a combination of two or more thereof.

6. A processing system according to any one of claims 1 to 5, characterized in that: include A laser system (1) for generating a laser beam required for processing; A spatial light modulator (5) for loading a phase modulation pattern and regulating the laser wavefront phase; Optical transmission module, used for beam shaping and focusing; Real-time monitoring module for visual feedback of the machining process; A computer control system (13) is used for phase image generation, SLM dynamic control and motion coordination of the XYZ translation stage (12).

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