Modification processing method and system based on beam shaping

Abstract

The invention provides a modification processing method and processing system based on beam shaping, and the method comprises the following steps: obtaining three-dimensional light field distribution corresponding to a three-dimensional model through a holographic algorithm according to the three-dimensional model of a target modification structure, and generating a phase modulation diagram; loading the phase modulation diagram through a spatial light modulator, and modulating the wavefront phase of the incident laser, so that a light beam is focused on the surface of the material or in the material to form a preset spatial curved surface light field; and the spatial curved surface light field is focused on the material, so that the material in the light field region is subjected to nonlinear absorption or phase change, and a modified structure of a three-dimensional model is directly formed. According to the method, the limitation of traditional point-by-point scanning type machining is broken through, the machining efficiency and flexibility of a complex three-dimensional structure are remarkably improved, the method is suitable for scenes such as transparent material internal waveguide inscribing, curved surface splinter separation, large-area stripping, functionalized surface preparation and opaque material huge removal machining, and the machining efficiency and quality are remarkably improved.

Description

Technical Field

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

[0002] Due to its advantages such as high precision, non-contact, and wide range of applicable materials, laser processing technology has been widely used in the fields of micro-nano manufacturing, optical device processing, semiconductors, etc. However, with the evolution of industrial demands towards complex three-dimensional structures, high efficiency, and high consistency, the limitations of traditional laser processing technology have become increasingly prominent.

[0003] Traditional laser processing mostly uses Gaussian beams or focusing methods with a fixed focal depth, and the focal position is adjusted by mechanically moving optical elements (such as objective lenses or sample stages). This mode has problems such as low efficiency, limited precision, and lack of flexibility. Existing focal point control technologies mainly rely on schemes such as acousto-optic modulators (AOMs), galvanometer scanners, or tunable lenses, but they have significant defects. For example, although the AOM scheme can achieve nanosecond-level focal point switching, its modulation freedom is low, only supporting one-dimensional or simple two-dimensional path adjustments, and it is difficult to generate complex three-dimensional focal point distributions. Galvanometer scanning systems rely on the deflection of high-speed mirrors, the focal point movement range is limited by the optical design, and high-speed movement is prone to thermal drift and mechanical wear; tunable lenses (such as liquid crystal lenses) have a slow response speed (millisecond level), are difficult to meet the requirements of high repetition rate processing, and have a limited focal depth control range.

[0004] To improve processing efficiency, some technologies attempt to generate static multi-focal points through diffractive optical elements (DOEs) or lens arrays. However, such schemes have problems such as poor uniformity, lack of flexibility, and difficulty in three-dimensional expansion, and there are also many challenges in technologies for processing complex three-dimensional structures, such as application challenges in generating longitudinal modified surfaces, controlling curved surface fragmentation, and manufacturing waveguides.

[0005] Although spatial light modulators (SLMs) have been used for phase modulation, their application in laser processing is still limited to simple two-dimensional pattern generation or static holographic projection, and their potential for flexible control has not been fully exploited.

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

[0007] In view of the shortcomings of the prior art, the present invention provides a modification processing method and processing system based on beam shaping, which uses light field control technology to shape the laser focal plane into a preset spatial light field (such as complex curves and surfaces), and uses the light field to perform "one-step" spatial modification of the material, and can also perform dynamic scanning spatial modification with surfaces as units that change over time. This method breaks through the limitations of traditional point-by-point scanning processing, significantly improves the processing efficiency and flexibility of complex three-dimensional structures, and is suitable for scenes such as internal waveguide writing of transparent materials, separation of curved cracks, large-area peeling, functionalized surface preparation, and massive 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 comprises the following steps:

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

[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 on the surface or inside of the material into a preset spatial curved surface light field;

[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 the three-dimensional model.

[0013] Furthermore, the spatial curved surface light field is a static light field, and the wavefront phase of the incident laser is statically 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 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 as a preset spatial curved surface light field; the spatial curved surface light field is used to perform dynamic scanning spatial modification of the material to be processed "with the surface as the unit" to directly form the structure of a three-dimensional model.

[0015] Furthermore, 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:

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

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

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

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

[0020]

[0021] Add to to obtain the superimposed phase diagram of the jth machining point =mod + 2 , where mod[] represents taking the remainder of the quotient of + divided by 2 ;

[0022] Obtain the set of superimposed phase diagrams of N machining points, denoted as ;

[0023] Add to the SLM in sequence according to the dynamic time interval to form a dynamic spatial curved surface light field.

[0024] Furthermore, based on the iterative algorithm, the phase distribution corresponding to each slice is deduced in reverse, specifically including the following steps:

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

[0026] Propagate forward along the optical axis direction to obtain the light fields of K planes, where the forward propagation is specifically: the light field propagated from the (k - 1)th plane to the kth plane is updated according to the following expression, and the expression is:

[0027]

[0028] Among them, is the two-dimensional inverse fast Fourier transform, and FFT2 is the two-dimensional fast Fourier transform. is the transfer function. , where in the formula is the number of wave peaks in the x direction per unit length. is the number of wave peaks in the x direction per unit length. , where m and n are frequency indices used to correspond to discrete positions in the frequency domain, m ∈ ; n ∈ ; is the laser wavelength;

[0029] Starting from the K plane along the reverse direction of the optical axis, according to reverse substitution and propagation, the optical field amplitude is successively replaced with the target light intensity while retaining the phase. Specifically:

[0030] The target light intensity on the K plane is expressed as: ; where is the phase angle function for extracting the complex number;

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

[0032]

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

[0034]

[0035] Among them, represents the target light intensity on the SLM plane.

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

[0037]

[0038]

[0039] Among them: is the laser wavelength; NA is the numerical aperture of the system, 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; f is the focal length.

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

[0041] A processing system for a modified processing method based on beam shaping includes a laser system for generating a laser beam required for processing; a spatial light modulator for loading a phase modulation diagram 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 diagram generation, SLM dynamic control, and motion coordination of an XYZ translation stage.

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

[0043] 1. The modification processing method based on beam shaping described in the present invention uses the spatial curved surface light field to perform "one-step" spatial modification of materials, and can also perform dynamic scanning spatial modification with curved surfaces as units that change over time. This method breaks through the limitations of traditional point-by-point scanning processing, significantly improves the processing efficiency and flexibility of complex three-dimensional structures, and is suitable for scenes such as internal waveguide writing of transparent materials, curved surface crack separation, large-area peeling and functional surface preparation.

[0044] 2. The modified processing method based on beam shaping described in the present invention uses SLM phase modulation to directly control the three-dimensional coordinates of the focus, avoiding inertial errors and vibrations introduced by mechanical movement. It can achieve accurate reproduction of complex geometries, support the generation of focal planes of any preset curves, surfaces or inclined surfaces, and the deviation between the processing path and the design model is very small, which is particularly suitable for high-fidelity manufacturing of optical components (such as Fresnel lenses and free-form surfaces).

[0045] 3. The modification processing method based on beam shaping described in the present invention has a dynamic mode that flexibly adapts to continuous processing and switches through real-time phase diagrams to achieve spatial focal plane movement along a three-dimensional trajectory (such as spiral drilling and special-shaped cutting), which is suitable for complex component processing. The static mode efficiently covers a large area to generate a spatial light field, and a single exposure can complete the surface functionalization of the beam focus area (such as super-hydrophobic micro-nano structure), with high processing consistency.

[0046] 4. The modification processing method based on beam shaping described in the present invention can achieve non-destructive modification inside transparent materials such as glass, sapphire, and crystal through nonlinear absorption effect, breaking through the limitation of traditional technology on surface processing. The present invention induces clean cracking by longitudinally penetrating the modified surface, which is suitable for curved surface separation of brittle materials such as sapphire and silicon wafers, with low edge roughness and high yield rate. Polymer and film processing: The low-energy static multi-focus mode of the present invention can perform microstructural processing on flexible materials such as PI film and PDMS to avoid thermal damage.

[0047] 5. The modified processing method based on beam shaping according to the present invention expands the dimension of laser processing from a two-dimensional plane to a three-dimensional space through spatial curved light field control technology, achieving a leapfrog breakthrough in terms of efficiency, precision, flexibility, and applicability, providing a new solution for the high-value-added precision manufacturing field and having significant industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained obviously without creative efforts based on these drawings.

[0049] Figure 1 It is a schematic diagram of the modified processing system based on beam shaping according to the present invention.

[0050] Figure 2 It is a schematic diagram of processing a three-dimensional optical device by the modified processing method based on beam shaping according to the present invention.

[0051] Figure 3 It is a partial focal plane and three-dimensional structure shape.

[0052] Figure 4 It is a schematic diagram of processing a curved crack by the modified processing method based on beam shaping according to the present invention.

[0053] Figure 5 It is a schematic diagram of processing two-dimensional group holes by the dynamic-static combined modified processing method based on beam shaping according to the present invention.

[0054] In the figure:

[0055] 1 - laser system, 2 - beam expander, 3 - attenuation sheet, 4 - reflector, 5 - spatial light modulator, 6 - convex lens, 7 - beam splitter, 8 - white light source, 9 - CCD, 10 - dichroic mirror, 11 - processing sample, 12 - X-Y-Z translation stage, 13 - computer control system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The following will describe in detail the embodiments of the present invention. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention and should not be construed as a limitation to the present invention.

[0057] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These 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. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise specifically defined.

[0058] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] As Figure 2 shown, the modified 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 a holographic algorithm, and a phase modulation map is generated;

[0061] The phase modulation map 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 surface light field is used to focus on the material, so that the material in the light field region undergoes non-linear absorption or phase change, directly forming the modified structure of the three-dimensional model, without the need for point-by-point scanning of the focus in traditional laser modification, and realizing modified processing.

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

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

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

[0066] Example 1

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

[0068] According to the three-dimensional model of the target modification structure, the three-dimensional light field distribution corresponding to the three-dimensional model is obtained through the holographic algorithm, and a phase modulation map is generated.

[0069] The phase modulation map 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 surface light field on the surface or inside the material; the static modulation is based on an iterative algorithm to inversely determine the phase distribution.

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

[0071] The processing process is feedback-controlled through a real-time monitoring system to ensure processing accuracy and consistency.

[0072] Based on the iterative algorithm, the phase distribution corresponding to each slice is inversely deduced, specifically including the following steps:

[0073] The target three-dimensional model is equally spaced sliced into K planes along the optical axis direction, and the slice spacing is Δl. The slice spacing Δl satisfies the following conditions:

[0074]

[0075]

[0076] Where: is the laser wavelength (unit: nm); NA is the system numerical aperture, dimensionless; Δx, Δy are the SLM pixel sizes (unit: micrometers); 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 k-th section and the SLM; the light intensity of the k-th section is ; Set a random phase = rand(x, y) × 2π, where rand(x, y) represents generating a random number in the range of [0, 1] at (x, y), (x, y) represents the pixel position, x ∈ , y ∈ ; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; the initial light field , i is the imaginary unit;

[0078] Propagate forward along the optical axis to obtain the light fields of K planes. The forward propagation is specifically as follows: The light field propagated from the (k - 1)-th plane to the k-th plane is updated according to the following expression, and the expression is:

[0079]

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

[0081] Starting from the K plane, propagate in the reverse direction along the optical axis according to reverse substitution and propagation, and successively replace the light field amplitude with the target light intensity, while retaining the phase. Specifically:

[0082] The target light intensity of the K plane is expressed as: ; where is the phase angle function for extracting the complex number;

[0083] The light intensity propagated from the k-th plane to the (k - 1)-th plane in the reverse direction along the optical axis is updated according to the following expression, and the expression is:

[0084]

[0085] After propagating in the reverse direction to the SLM plane, update the phase:

[0086]

[0087] where, represents the target light intensity of the SLM plane.

[0088] Illustrative example

[0089] The processed three-dimensional structure is as Figure 2 shown in a, and the three-dimensional structure is similar to a V-shaped three-dimensional structure;

[0090] Such as Figure 2 shown in b, the plane slice in the Z direction, the pixel size of each slice is 1272*1024, and the number of slices is determined by the distance between adjacent slices. The slice distance is (unit: mm), and there is:

[0091]

[0092]

[0093] The number of pixels using SLM is 1272*1024, the pixel size is 12.5 microns, the focal length is 300 mm, and the laser wavelength is 1064 nm. Then the numerical aperture NA of the system can be obtained as: 0.0335. Then there is , since the processing is precision processing, the higher the resolution, the better. Then select close to the minimum value is the best. In the embodiment, the processed three-dimensional structure is 1 mm thick. Let . Then the number of plane slices is 1 mm / 0.02 mm = 50 slices, and the adjacent interval of each slice is 0.02 mm.

[0094] Divided into 50 planes along the optical axis (z direction), and the distance between the k-th section and the SLM is ; Such as Figure 2 shown in the light intensity distribution slice diagram of c, the light intensity of the k-th section is ; Process the slice, let the light intensity value of the physical part of the slice be 1 (corresponding to black in the grayscale image), and the empty part take 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 in (-636, 635), y ∈ , that is, y is in (-512, 511); The initial light field .

[0095] The light field of K planes is obtained according to the forward propagation along the optical axis direction. The forward propagation is specifically: the light field propagated from the (k-1)-th plane to the k-th plane is updated according to the following expression, and the expression is:

[0096]

[0097] Among them, is the two-dimensional inverse fast Fourier transform, and FFT2 is the two-dimensional fast Fourier transform. is the transfer function. , where is the number of wave crests in the x direction per unit length. is the number of wave crests 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 reverse direction along the optical axis, according to reverse substitution and propagation, the optical field amplitude is successively replaced with the target light intensity while retaining the phase. Specifically:

[0099] The target light intensity on the K plane is expressed as: ; where is the phase angle function for extracting complex numbers;

[0100] Propagate in the reverse direction to the previous plane, that is, propagate in the reverse direction from back to front ( ). The light intensity propagated from the kth plane to the k - 1th plane in the reverse direction along the optical axis according to reverse propagation is updated according to the following expression, and the expression is:

[0101]

[0102] After propagating in the reverse direction to the SLM plane, update the phase:

[0103]

[0104] Among them, represents the target light intensity on the SLM plane.

[0105] Convergence judgment: Repeat forward propagation and reverse propagation, and replace with for iteration until the error is less than the threshold (the threshold is taken as 0.001) or the maximum number of iterations is reached, and finally the target phase diagram is obtained.

[0106] Using the optical system shown in Figure 1 , a picosecond laser system generates 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, and this laser must completely cover the panel of the SLM. The processed sample has a thickness of 5 mm, a size of 5 mm * 5 mm * 5 mm, and the processed sample is made of plexiglass material, polished on each side, transparent, and used for making optical devices.

[0107] Place the sample on the platform and only perform light irradiation for 0.5 s. The irradiation time is determined by the sample material and the laser. Finally, an optical device as shown in Figure 2 d can be obtained. In addition to the V-groove type optical device in this case, this method can also be used to process various three-dimensional spatial structures or waveguide structures as shown in Figure 3 .

[0108] Example 2

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

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

[0111] Load the phase modulation map 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 surface light field on the surface or inside the material;

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

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

[0114] Based on the iterative algorithm, inversely determine the phase distribution , which is the same as static modulation;

[0115] Generate a phase map for changing the focusing position according to the dynamic movement of the focusing position, specifically:

[0116] Obtain the processing path according to the three-dimensional model, divide the processing path into N processing points according to the spatial height, j ;

[0117] The spatial coordinates of the jth processing point , where is the distance from the jth processing point to the last lens plane of the 4f system. Then, the phase map loaded on the SLM at the jth processing point is:

[0118]

[0119] Add to to obtain the superimposed phase map at the jth processing point =mod + 2 , where mod[] represents taking + For 2 the remainder of the quotient of;

[0120] Obtain the set of phase diagrams after superimposing N machining points, denoted as ;

[0121] Load the phase diagrams of the machining points in into the SLM at dynamic time intervals in sequence to form a dynamic spatial curved surface optical field.

[0122] Illustrate with examples

[0123] Inversely determine the phase distribution based on the iterative algorithm , The generation method is the same as that of static modulation. Refer to the static modulation part in Embodiment 1 to generate a spatial structure as shown in Figure 4 a in

[0124] Obtain the machining path according to the 3D model. In Embodiment 2, we need to cut a quartz wafer as shown in Figure 4 . Its size is 1*10*30 mm, and we need to cut a length of 10 mm. The sample is placed at the position with spatial coordinates (0, 0, 300). Then the machining path is from (5, 0, 300) to (-5, 0, 300), and the machining path is a straight line. Set the dynamic spatial interval to 0.05 mm, then 200 machining points are required for a 10 mm spacing; the machining points according to the machining path 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 j-th machining point be , where is the distance from the j-th machining point to the last lens plane of the 4f system. Then the phase diagram of the j-th machining point loaded on the SLM is:

[0126]

[0127] Superimpose onto to obtain the phase diagram of the j-th machining point after superimposition =mod + 2 , where mod[] represents taking the + For 2 the remainder of the quotient of;

[0128] Obtain a set of phase diagrams after superposition of N processing points, denoted as ;

[0129] Load the phase diagrams of the processing points in into the SLM at intervals of 0.1 s in dynamic time in sequence to form a dynamic spatial curved surface light field.

[0130] Use the optical system as shown in Figure 1 . The picosecond laser system generates a laser with a wavelength of 1064 nm, a pulse width of 10 ps, an average power of 30 W, and a repetition frequency of 100 kHz, and load the phase diagram onto the SLM in sequence. Set the laser power to 30 W and perform processing as shown in Figure 4 b.

[0131] Obtain the curved surface cutting effect as shown in Figure 4 c.

[0132] Example 3:

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

[0134] S01: According to the three-dimensional model of the target modification structure, obtain the three-dimensional light field distribution corresponding to the three-dimensional model through the holographic algorithm, generate a phase modulation diagram, and inversely determine the phase distribution based on the iterative algorithm , The generation method is the same as that of static modulation. Refer to the static modulation part in Example 1 to generate the spatial structure as shown in Figure 5 a.

[0135] S02: Use the one as shown in Figure 1The optical system shown, the picosecond laser system generates a laser with a wavelength of 1064 nm, a pulse width of 10 ps, a repetition frequency of 100 kHz, and a laser power of 15 W. The processed sample is plexiglass, with dimensions of 3 mm * 9 mm * 1 mm, and the coordinates of its center point are (0, 0, 300), with all units in mm; then the coordinate positions that require 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). The dynamic moving focusing position obtains a set of phase diagrams according to the method of Example 2, such as Figure 5 as shown in b in, 27 processing points are obtained, and are respectively denoted as 1, 2,..., 27 in the order of the above coordinate points; the set of superimposed phase diagrams is denoted as .

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

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

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

[0139] S04: According to the rules in step S03, perform dynamic switching of positions. The switching time for each phase diagram is 1 s, and the switching order of the phase diagrams 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. Perform static irradiation for 1 s at each coordinate position, and then perform dynamic switching in the above order. In this way, the processing combining dynamics and statics is completed, and the processed finished product as shown in Figure 5 is obtained as shown in c in

[0140] In addition, for the modification processing method based on beam shaping described in the present invention, the spatial curved surface modification can be used for the flaking processing of brittle materials parallel to the surface, can be used for the chipping processing of brittle materials perpendicular to the surface, can also be supplemented with chemical etching methods for the internal space microchannel processing of brittle materials, and can also be used for the high-efficiency processing of removing materials from non-transparent materials.

[0141] As Figure 1 shown, the curved 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 regulate the phase of the laser wavefront; the optical transmission module includes a beam expander 2, an attenuation sheet 3, a reflector 4, a beam splitter 7, an objective lens 11, and a convex lens 6, and is used for the shaping and focusing of the light beam; the real-time monitoring module includes a CCD 9 and a dichroic mirror 10, and is used for the visual feedback of the processing process; the computer control system 13 is used for phase diagram generation, SLM dynamic control, and the motion coordination of the X-Y-Z translation stage 12.

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

[0143] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not used to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included within the protection scope of the present invention.

Claims

1. A modified processing method based on beam shaping, characterized in that, It includes the following steps: According to the three-dimensional model of the target modification structure, obtain the three-dimensional light field distribution corresponding to the three-dimensional model through the holographic algorithm, and generate a phase modulation map. Load the phase modulation map 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 of the material. Use the spatial curved surface light field to focus on the material, so that the material in the light field area undergoes non-linear absorption or phase change, and directly form the modified structure of the three-dimensional model.

2. The method for modified processing 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 into a preset spatial curved surface light field on the surface or inside of the material; use the spatial curved surface light field to perform one-step spatial modification on the material to be processed, and directly form the structure of the three-dimensional model; the static modulation is based on an iterative algorithm to inversely determine the phase distribution.

3. The beam shaping-based modification processing method according to claim 1, wherein, 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 into a preset spatial curved surface light field on the surface or inside of the material; use the spatial curved surface light field to perform dynamic scanning spatial modification of "taking the surface as a unit" on the material to be processed, and directly form the structure of the three-dimensional model.

4. The modified processing method based on beam shaping according to claim 3, characterized in that, Making the light beam be focused into a preset spatial curved surface light field on the surface or inside of the material through dynamic modulation specifically includes the following steps: Backward determination of phase distribution based on an iterative algorithm ; Generate a phase map for changing the focusing position according to the dynamic movement of the focusing position, specifically: The machining path is obtained based on the three-dimensional model, and the machining path is divided into N machining points according to the spatial height, j ; Let the spatial coordinates of the j-th processing point , where is the distance from the j-th processing point to the last lens plane of the 4f system. Then, the phase diagram loaded on the SLM at the j-th processing point is as follows: ； Add to to obtain the phase diagram of the j-th processing point after superposition = mod + 2 , where mod[] represents taking the remainder of the quotient of + divided by 2 ; Obtain a set of phase diagrams after superimposing N processing points, denoted as ; Load The phase diagrams of the machining points in are sequentially loaded into the SLM at dynamic time intervals to form a dynamic spatial curved surface optical field.

5. The method for modified processing based on beam shaping according to claim 2 or 4, characterized in that, Based on the iterative algorithm, inversely deduce the phase distribution corresponding to each slice, specifically including the following steps: The target 3D model is sliced into K planes at equal intervals along the optical axis direction, and the slice interval is Δl; is the distance between the k-th section plane and the SLM; the light intensity of the k-th section plane is ; Set the random phase = rand(x,y) × 2π, where rand(x,y) represents generating a random number in the range of [0,1] at (x,y), (x,y) represents the pixel position, x ∈ , y ∈ ; Nx is the number of pixels in the x direction; Ny is the number of pixels in the y direction; the initial light field , where i is the imaginary unit; Obtain the light fields of K planes along the optical axis direction according to the forward propagation. The forward propagation is specifically: the light field propagated from the (k - 1)-th plane to the k-th plane is updated according to the following expression, and the expression is: ； Among them, is the two-dimensional inverse fast Fourier transform, FFT2 is the two-dimensional fast Fourier transform, is the transfer function, , where in the formula is the number of wave peaks in the x direction per unit length, is the number of wave peaks in the x direction per unit length, , where m and n are frequency indices used to correspond 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 along the reverse direction of the optical axis, according to the reverse substitution and propagation, sequentially replace the light field amplitude with the target light intensity and retain the phase, specifically: Target light intensity on the K plane It is expressed as: ; where Phase angle function for extracting complex numbers; The light intensity propagated from the k-th plane to the (k - 1)-th plane along the reverse direction of the optical axis is updated according to the following expression, and the expression is: ； After propagating reversely to the SLM plane, update the phase: ； Among them, represents the target light intensity of the SLM plane.

6. The beam shaping-based modification processing method according to claim 5, characterized in that The slice spacing Δl satisfies the following conditions: ， ； Wherein: 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; f is the focal length.

7. The beam shaping-based modification processing method according to claim 1, wherein The shape of the focal plane of the spatial curved surface light field is one of a plane, an inclined plane, and a curved surface, or a combination of two or more of them; the spatial curved surface light field includes one of a plane light field, a curved surface light field, a curved line light field, and a discrete dot matrix light field, or a combination of two or more of them.

8. A processing system for a modification processing method based on beam shaping according to any one of claims 1-7, characterized in that, It includes A laser system (1) for generating a laser beam required for processing; A spatial light modulator (5) for loading a phase modulation map and controlling the laser wavefront phase; An optical transmission module for beam shaping and focusing; A real-time monitoring module for visual feedback during the processing; A computer control system (13) for phase map generation, SLM dynamic control, and motion coordination of the X-Y-Z translation stage (12).

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