A high-precision, high-energy three-dimensional array ultrafast laser processing method

Abstract

This invention relates to the field of laser 3D manufacturing technology, specifically disclosing a high-precision, high-energy 3D array ultrafast laser processing method. It applies a multi-plane noise threshold filtering algorithm to generate a high-precision, high-energy 3D array ultrafast laser light field, enabling the spatial shaping of a single-pulse laser beam from a standard Gaussian distribution into a 3D array light field. The number of layers in this 3D array is adjustable from 1 to 6, and the interlayer spacing is adjustable from 1µm to 100µm. Each layer can accommodate up to 400 laser focusing points (20*20). Utilizing a spatial 4f laser transport system and a laser focusing objective, this invention enables high-quality 3D lattice array structure processing under single-pulse conditions within any transparent material. The minimum diameter of the processed array structure reaches 200nm, with an in-plane lattice spacing of 500nm and an inter-plane lattice spacing of 1µm. This invention significantly improves the accuracy and efficiency of laser 3D additive and subtractive manufacturing, and is applicable to the field of 3D manufacturing.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional additive and subtractive material manufacturing technology, and in particular to a high-precision, high-energy three-dimensional array ultrafast laser processing method. Background Technology

[0002] In the field of laser processing, traditional laser focusing spots are 0-dimensional focal points, making the processing of planar and three-dimensional structures extremely time-consuming. Therefore, spatial shaping methods such as dual-focus, multi-focus, and laser focal lines have been gradually proposed to further improve processing efficiency. In recent years, planar patterning technology using devices such as liquid crystal spatial light modulators (SLMs) and digital micromirror arrays (DMDs) has matured, offering significant advantages in planar pattern processing, including processing accuracy, efficiency, and consistency. However, shaping lasers into three-dimensional structures is difficult. DMDs, limited by their shaping principles, struggle to extend from planar to three-dimensional; while SLMs possess axial control capabilities, they suffer from severe axial crosstalk, and the three-dimensional light field used for processing must maintain extremely high energy uniformity and intensity; otherwise, it cannot be used for laser processing. Therefore, one-step processing of three-dimensional structures is extremely challenging. Consequently, one-step processing of three-dimensional structures is of great significance in the field of laser processing, such as internal engraving of three-dimensional structures in laser subtractive / equal material processing and simultaneous aggregation of three-dimensional structures in laser additive processing.

[0003] Therefore, how to solve the problem of low manufacturing speed in order to improve the accuracy and efficiency of three-dimensional structure processing is an urgent technical problem that needs to be solved. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a high-precision, high-energy three-dimensional array ultrafast laser processing method to achieve high-precision, high-energy three-dimensional array processing light field generation, resulting in uniform laser energy distribution, high utilization rate, and improved accuracy and efficiency of three-dimensional structure processing.

[0005] To achieve the above objectives, this invention provides a high-precision, high-energy three-dimensional array ultrafast laser processing method, the technical solution of which is as follows:

[0006] A high-precision, high-energy three-dimensional array ultrafast laser light field generation method, the method comprising:

[0007] Based on the multi-plane noise threshold filtering algorithm, the energy of the array point region is limited to 1 and the noise region of the non-array point region is limited to a set ratio on the basis of the initial multi-plane optical field, thus obtaining a three-dimensional array ultrafast laser optical field. The initial multi-plane optical field is formed by combining Fresnel transformation and multi-plane algorithm.

[0008] The three-dimensional array ultrafast laser field includes at least one optical shaping three-dimensional array layer. Each optical shaping three-dimensional array layer can accommodate a maximum of 20*20 dots, totaling 400 dots. When the three-dimensional array ultrafast laser field includes at least two optical shaping three-dimensional array layers, the interlayer spacing between each optical shaping three-dimensional array layer is not fixed.

[0009] Preferably, when the three-dimensional array ultrafast laser light field includes at least two optical shaping three-dimensional array layers, the interlayer spacing of each optical shaping three-dimensional array layer is adjusted within the range of 1µm to 100µm.

[0010] Preferably, the number of layers in the optical shaping three-dimensional array layer is adjusted within the range of 1 to 6 layers.

[0011] Preferably, the noise level of the non-array point noise region is not higher than 50% of the energy density of the array point region.

[0012] Preferably, the three-dimensional array ultrafast laser field is used to process the interior of transparent materials.

[0013] Preferably, the transparent material includes one of quartz glass and transparent gel.

[0014] A method for one-step data writing and processing of a three-dimensional array ultrafast laser field inside a transparent material, characterized in that, based on the three-dimensional array ultrafast laser field constructed as described above, the processing method includes:

[0015] The pre-designed phase diagram of the stereo array is input into the liquid crystal spatial light modulator, and the corresponding stereo array light field is constructed in the optical path by using lens Fourier transform. After being transported by a 4f lens, the zero-order light is removed by a filter, and the objective lens is focused into the interior of the transparent material to realize the one-step three-dimensional processing of the stereo array.

[0016] Preferably, when the liquid crystal spatial light modulator acquires the pre-designed 3D array phase map, different phase maps are frequently called from a preset phase map library, and combined with the appropriate displacement stage movement speed and laser pulse frequency, the processing of any desired array can be achieved.

[0017] The present invention has at least the following beneficial effects:

[0018] 1. This invention enables the generation of ultrafast laser light fields in a three-dimensional array in space. The number of light field array layers is adjustable from 1 to 6, with each layer accommodating a maximum of 20*20 lattice array area of ​​400 dots. The interlayer spacing is adjustable from 1µm to 100µm. Laser pulses ranging from femtosecond to continuous have a shaping effect, with a light field shaping energy utilization rate exceeding 50%. The maximum energy of the three-dimensional array light field can reach 10W, while the energy distribution uniformity is over 95%.

[0019] 2. This invention utilizes the low-energy penetrability and high-energy destructive power of lasers. The shaped three-dimensional array laser light field can perform additive, subtractive, or equal-material processing within any transparent material without damaging the material surface. It has particularly high-quality processing capabilities for hard and brittle materials such as quartz glass and sapphire, as well as difficult-to-process materials such as flexible materials like PVA and PAAm. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 The flowchart for generating the three-dimensional array phase map of the present invention includes a code generation process and a noise threshold filtering process.

[0022] Figure 2 This is a schematic diagram of the spatial three-dimensional array light field generation effect of the present invention, wherein: a) is the phase grayscale image corresponding to the three-dimensional array, b) is the three-dimensional array light field, c) is the light field layer display diagram, and d) is the multi-layer light field energy distribution.

[0023] Figure 3 This is a diagram illustrating the processing results of the multi-planar three-dimensional array of the present invention.

[0024] Figure 4 This is a detailed illustration of a single plane in the multi-plane processing array of the present invention.

[0025] Figure 5 The change in fluorescence properties of the material with or without AuCl3 doping during processing. Detailed Implementation

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0027] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0030] Example 1:

[0031] This invention provides a method for generating a high-precision, high-energy three-dimensional array ultrafast laser light field. The method includes: based on a multi-plane noise threshold filtering algorithm, limiting the energy of the array point region to 1 and the noise region of the non-array point region to below a set ratio, based on a preliminary multi-plane light field, to obtain a three-dimensional array ultrafast laser light field. The preliminary multi-plane light field is formed by combining Fresnel transformation and the multi-plane algorithm. The three-dimensional array ultrafast laser light field includes at least one optically shaped three-dimensional array layer. Each optically shaped three-dimensional array layer can accommodate a maximum of 20*20 points, totaling 400 points. When the three-dimensional array ultrafast laser light field includes at least two optically shaped three-dimensional array layers, the interlayer spacing of each optically shaped three-dimensional array layer is not fixed.

[0032] The generation process of the three-dimensional array ultrafast laser field includes generating a three-dimensional array phase map and generating the three-dimensional array ultrafast laser field based on the three-dimensional array phase map. The process of generating the three-dimensional array phase map is as follows: Figure 1 As shown, the process for generating a three-dimensional array laser light field is as follows: Figure 2 As shown.

[0033] exist Figure 1In this model, a threshold filtering algorithm module is added to the basic GS algorithm loop. This module can reduce the energy limit on non-patterned areas, allowing more computing power to be used to improve the number of patterned layers and the energy density and uniformity of patterned areas.

[0034] Specifically, the threshold filtering algorithm for a single-pulse three-layer pattern is illustrated as follows:

[0035] ① Obtain the phase of the Gaussian amplitude A0 and the phase at the end of the previous cycle. (If this is the first loop, obtain the initial phase) ) is A i ,

[0036] ② The amplitude A of the k-th plane is obtained by superimposing the Fourier transform of the k-th plane. j With phase

[0037] ③ Normalize the amplitude value of the k-th plane, and take the minimum energy of the pattern region as the energy uniformity C of this plane. k (This value is between 0 and 1). Through threshold filtering logic, the amplitude of the first planar patterned region is replaced with a preset pattern amplitude, and the amplitude energy (noise energy) of the non-patterned region is reduced to less than 0.5 of the preset amplitude. In this way, the processing of the patterned region is distinguished from the non-patterned region (noise region) through the threshold effect, and the updated amplitude A is set. j+1 Replace A j ;

[0038] ④Then, the new amplitude A is obtained through inverse Fourier transform. i+1 With phase

[0039] ⑤ Perform a Fourier transform on the blank plane to determine whether its highest energy value exceeds 0.5 of the pre-designed energy. If it does, remove the excess part and proceed to the next step. If it does not exceed the limit, proceed directly to the next step.

[0040] ⑥ Repeat ①②③④⑤ once, where k = mod(k+1) / 3 (mod is the remainder);

[0041] ⑦ Repeat ⑥ until C1, C2, and C3 are all greater than 0.95 (adjust as needed);

[0042] ⑧ Output phase diagram

[0043] exist Figure 2 In the process, a three-dimensional pattern phase grayscale image is obtained based on the three-dimensional array phase map. Figure 2 In section a), and based on the phase grayscale image of the three-dimensional pattern, the three-dimensional array light field is obtained. Figure 2(b) The layered display of the three-dimensional array light field is as follows: Figure 2 As shown in c), this three-dimensional array light field is a three-dimensional array ultrafast laser light field, and the energy distribution of the three-dimensional array ultrafast laser light field is as follows. Figure 2 As shown in d).

[0044] In this embodiment, the overall energy distribution uniformity of the shaping region of the three-dimensional array ultrafast laser light field reaches more than 95%, and can reach more than 99% at its highest; the noise level of the non-shaping region is no higher than 50% of the energy density of the shaping region, and has no impact on the material during the processing; the minimum energy required at a single point is only 0.123uJ, and the overall energy utilization rate of the optical path exceeds 50%.

[0045] In one exemplary embodiment, a phase-type liquid crystal spatial light modulator is used, combined with Fresnel transform and multi-plane algorithm, to realize the generation of the light field of the entire three-dimensional spatial array; at the same time, for the suitable application environment of laser processing, an original multi-plane noise threshold filtering (M-NTF) algorithm is added to optimize the energy distribution of the shaped region and the noise distribution of the non-shaped region, making the three-dimensional array more suitable for application in the field of laser processing.

[0046] The three-dimensional array ultrafast laser field constructed by this invention can be used for processing inside any transparent material, making it very suitable for special precision processing of materials that are difficult to process by traditional methods, such as hard and brittle materials like quartz glass and soft and tough materials like transparent gels.

[0047] Example 2:

[0048] This invention provides a high-precision, high-energy three-dimensional array ultrafast laser light field generation and processing method, the specific implementation steps of which are as follows:

[0049] Step 1: Place 3g of acrylamide, 0.0015g of methylenebisacrylamide, and 10mL of deionized water into a test tube and sonicate for 10min. Then, rapidly add 0.02g of ammonium persulfate diluted 10 times and 10uL of N,N,N,N-tetramethylethylenediamine to the sonicated solution, stir quickly for 1 minute, pour into a mold, and let stand until a transparent PAAm hydrogel is formed.

[0050] Step 2: Pre-design the required 3D array pattern and import it into the multi-plane 3D array phase map calculation code in sequence. Use a noise threshold filtering algorithm that combines Fresnel transform and multi-plane calculation to output the phase grayscale image sequence corresponding to the multi-plane 3D array for processing preparation.

[0051] Step 3: After the femtosecond laser is polarized by a half-wave plate, it is irradiated onto the SLM. The required three-dimensional array light field is quickly shaped by calling the three-dimensional array phase grayscale image library. Combined with the 4f system to transport and adjust the size of the light field, the light field is finally focused into the transparent hydrogel with uniform quantum dot through the objective lens to realize the formation of a one-step three-dimensional structure array. At the same time, multi-pulse scanning is performed based on this method to realize the high-efficiency and high-precision manufacturing of three-dimensional continuous structures.

[0052] Based on the above processing method, ultra-high-speed optical storage capability can be achieved by processing three-dimensional dot arrays within the material, with a maximum data storage rate of 24 Mbit / s. By carbonizing PAAm with laser and spectral modulation of luminescent quantum dots, selective fluorescence characteristics within the transparent material can be adjusted. Three-dimensional array information can be read using a fluorescence microscope, thus realizing a complete, rapid, and high-density optical storage and retrieval process. Optical storage functionality is achieved through a high-precision, high-energy three-dimensional array ultrafast laser light field. Using an optimized phase grayscale image and rationally controlling the laser single-pulse energy through a half-wave plate combined with SLM, data points with a minimum diameter of 200 nm can be written, achieving a maximum data storage density of 4 Tbit / cm². 3 This embodiment compares the energy uniformity of the multi-planar optical field obtained by processing using the method provided in this embodiment with that of traditional methods (compared to the method of this invention that does not use noise control), and the results are as follows. Figure 3 As shown, from Figure 3 It can be seen that the method proposed in this invention has stronger energy uniformity. By combining noise control algorithm with energy balance control, this invention can improve the energy uniformity between multiple planes to over 95%, and can even reach over 99%.

[0053] The effect of multi-plane machining using the method proposed in this embodiment is shown as follows: Figure 3 and Figure 4 As shown, Figure 3 To demonstrate the effects of multi-plane machining, Figure 4 This demonstrates the internal processing effects of one of the planes. From Figure 3 As can be seen, this invention can process any dot matrix within a single pulse, and the inter-face distance and inter-face misalignment are adjustable. From Figure 4 It can be seen that the maximum number of planar dots in a single pulse can reach 400, and the minimum diameter of the processing point can reach 200nm.

[0054] Figure 5 The changes in fluorescence properties of materials after doping with Si-CQDs and AuCl3 are shown, from Figure 5 It can be seen that by selecting an appropriate ratio of Si-CQDs to AuCl3, the photoluminescence intensity in the laser processing area can be controlled, thereby improving the optical storage encryption capability.

[0055] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A high-precision, high-energy three-dimensional array ultrafast laser processing method, characterized in that, The method includes: Based on the multi-plane noise threshold filtering algorithm, the energy of the array point region is limited to 1, and the noise of the non-array point region is limited to a set ratio, thus obtaining a three-dimensional array ultrafast laser light field. The initial multi-plane light field is formed by combining Fresnel transformation and the multi-plane noise threshold filtering algorithm. The noise level of the non-array point noise region is no higher than 50% of the energy density of the array point region. The processing flow of the multi-plane noise threshold filtering algorithm includes: ① Obtain the phase of the Gaussian amplitude A0 relative to the end of the previous cycle. If it is the first loop, obtain the initial phase. ② The amplitude A of the k-th plane is obtained by superimposing the Fourier transform of the k-th plane. j and phase ③ Normalize the amplitude value of the k-th plane, and take the minimum energy of the pattern region as the energy uniformity C of this plane. k This value is between 0 and 1. Through threshold filtering logic, the amplitude of the first planar patterned region is replaced with a preset pattern amplitude, while the energy of the non-patterned region amplitude is reduced to below 0.5 of the preset amplitude. This threshold effect distinguishes between patterned regions and unprocessed non-patterned regions during processing. The updated amplitude A is then used to further differentiate between these regions. j+1 Replace A j Wherein, the amplitude energy of the non-patterned region is noise energy, and the non-patterned region is a noise region; ④ Obtain the new amplitude A through inverse Fourier transform. i+1 and phase ⑤ Perform a Fourier transform on the blank plane to determine whether its highest energy value exceeds 0.5 of the pre-designed energy. If it does, remove the excess part and proceed to the next step. If it does not exceed the limit, proceed directly to the next step. ⑥ Repeat ①②③④⑤ once, where k = mod(k+1) / 3, and mod is the remainder; ⑦ Repeat step ⑥ until C1, C2, and C3 are all greater than 0.95, and adjust accordingly based on actual conditions; ⑧ Output phase The three-dimensional array ultrafast laser field includes at least one optical shaping three-dimensional array layer. Each optical shaping three-dimensional array layer can accommodate a maximum of 20*20 dots, totaling 400 dots. When the three-dimensional array ultrafast laser field includes at least two optical shaping three-dimensional array layers, the interlayer spacing between each optical shaping three-dimensional array layer is not fixed.

2. The high-precision, high-energy three-dimensional array ultrafast laser processing method as described in claim 1, characterized in that, In the case where the three-dimensional array ultrafast laser light field includes at least two optical shaping three-dimensional array layers, the interlayer spacing of each optical shaping three-dimensional array layer is adjusted within the range of 1µm to 100µm.

3. The high-precision, high-energy three-dimensional array ultrafast laser processing method as described in claim 1, characterized in that, The number of layers in the optical shaping three-dimensional array is adjusted within the range of 1 to 6 layers.

4. The high-precision, high-energy three-dimensional array ultrafast laser processing method as described in claim 1, characterized in that, The three-dimensional array of ultrafast laser light fields is used to process the interior of transparent materials.

5. The high-precision, high-energy three-dimensional array ultrafast laser processing method as described in claim 4, characterized in that, The transparent material includes one of quartz glass and transparent gel.

6. A method for one-step data writing and processing of a three-dimensional array ultrafast laser field inside a transparent material, characterized in that, Based on the high-precision, high-energy three-dimensional array ultrafast laser processing method as described in any one of claims 1 to 5, the three-dimensional array ultrafast laser field is constructed, and the one-step data writing processing method for the three-dimensional array ultrafast laser field inside a transparent material includes: The pre-designed phase diagram of the stereo array is input into the liquid crystal spatial light modulator, and the corresponding stereo array light field is constructed in the optical path by using lens Fourier transform. After being transported by a 4f lens, the zero-order light is removed by a filter, and the objective lens is focused into the interior of the transparent material to realize the one-step three-dimensional processing of the stereo array.

7. The processing method as described in claim 6, characterized in that, When the liquid crystal spatial light modulator acquires the pre-designed three-dimensional array phase map, it calls different phase maps from the preset phase map library at high frequency, and combines them with the appropriate displacement stage movement speed and laser pulse frequency to realize the processing of any desired array.

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