A laser processing device and a laser processing method based on a superlens

Abstract

This invention relates to a laser processing apparatus and method based on a superlens. A superlens is configured on the emission side of a laser processing head to scan the surface of the sample to be laser-processed, acquiring sample surface data. The height of the superlens corresponding to the sample position is configured, and a processing laser is output. The processing laser, after being focused by the superlens, acts on the sample to form a modified layer. The apparatus uses a processing stage equipped with a translation mechanism to place the sample to be laser-processed, allowing the sample to move on a horizontal plane. A laser unit emits and shapes the laser beam. A focusing module equipped with a superlens works in conjunction with the translation mechanism and the laser unit, controlled by a controller. This invention forms a modified layer of uniform depth, has good monochromatic laser focusing effect, and is lighter overall. After the processing laser is focused by the superlens, spherical aberration correction in the optical axis direction and multi-spot output of the laser beam are achieved. The former reduces material loss during laser ablation and improves the surface roughness of the sample after ablation, while the latter improves processing efficiency.

Description

Technical Field

[0001] This invention relates to the technical fields of brazing or desoldering; welding; cladding or plating by brazing or welding methods; localized heating cutting, such as flame cutting; and processing with laser beams, and particularly to a laser processing apparatus and method based on a superlens. Background Technology

[0002] In recent years, with the rapid development of laser technology, control technology, and materials science, laser processing technology has been widely applied in industrial manufacturing, medical, communications, aerospace, and other fields. Focusing a laser beam using an objective lens is a common processing method in laser processing. However, objectives typically consist of multiple lenses, which are difficult to dissipate heat effectively under prolonged high-power laser irradiation. The accumulated heat causes thermal deformation and changes in refractive index in the lens materials, affecting the performance and stability of the optical system. Although cooling devices can alleviate the heat dissipation problem, this makes the system complex, bulky, and increases costs. Furthermore, traditional objectives are usually designed for correcting spherical aberration in air. For applications involving processing within materials, traditional objectives also face the challenge of spherical aberration correction, often requiring additional optical components, which further increases system complexity. Therefore, determining a lightweight optical element that can reduce thermal drift, maintain high optical performance, and correct aberrations has become a crucial aspect of current laser precision processing.

[0003] Chinese Patent CN119387899A discloses a laser processing apparatus, a method for cutting silicon carbide ingots, and a laser processing system. It optimizes the focal point size by using a beam shaping element to shape a Gaussian beam into a linear beam. This linear beam, after being focused by a lens, has a smaller spot size along the optical axis, reducing crack propagation along the optical axis and thus lowering the surface roughness of the ingot after peeling. However, prolonged laser exposure to the lens causes it to heat up and deform, leading to a drift in the laser focal point and affecting processing accuracy.

[0004] Chinese patent CN119126332A discloses a precision-machined scanning lens for femtosecond lasers. This method utilizes the design of concave-convex lenses with negative refractive indices, concave-convex lenses with positive refractive indices, convex-concave lenses with positive refractive indices, concave-convex lenses with negative refractive indices, biconvex lenses with positive refractive indices, biconcave lenses with negative refractive indices, biconvex lenses with positive refractive indices, and convex-concave lenses with negative refractive indices to achieve the output of a focused circular spot, thereby reducing the heat-affected zone. However, this method requires the combination of lenses with multiple parameters, making the system relatively complex, bulky, and costly.

[0005] Chinese patent CN118577973A discloses a SiC ingot stripping device and method. The device includes a laser generator, a beam expander module, a power adjustment module, a beam polarization modulation module, a mirror module, a beam shaping module, a 4f optical system, a second mirror module, and a focusing lens. Through the cooperation of the beam expander module, the beam polarization modulation module, the beam shaping module, and the 4f optical system, the size of the beam spot can be modulated and multi-focal output can be achieved. At the same time, it can effectively suppress spherical aberration caused by long-distance laser propagation. However, this method requires the cooperation of multiple modules, the optical path is complex, and it also suffers from the problem of thermal deformation.

[0006] In summary, traditional objectives cannot avoid focus drift caused by thermal deformation, and there is an urgent need for a new type of optical device that can maintain high optical performance in high-power laser processing. Summary of the Invention

[0007] This invention solves the problems existing in the prior art and provides a laser processing device and laser processing method based on a superlens.

[0008] The technical solution adopted in this invention is a laser processing method based on a superlens, the method comprising the following steps:

[0009] S1 is equipped with a superlens and is located on the emission side of the laser processing head;

[0010] S2 scans the surface of the sample to be laser-processed to obtain sample surface data;

[0011] S3 configures the height of the superlens corresponding to the sample location based on the sample surface data;

[0012] The S4 outputs a processing laser, which is focused by a superlens and applied to the sample to form a modified layer.

[0013] Preferably, in S1, a phase representation of the superlens plane that eliminates spherical aberration is established.

[0014]

[0015] Where ρ is the normalized radius of the emitted laser light, λ is the wavelength of the incident light, and r is the distance from the location of each nanopillar of the superlens to the center of the superlens. Focal length n is the processing depth of the sample to be laser-processed, n3 is the refractive index of the sample to be laser-processed, NA is the numerical aperture of the superlens, and n2 is the refractive index of air.

[0016] Preferably, the phase distribution is adjusted based on the diameter of each nanopillar.

[0017] Preferably, the diameter of each nanopillar r satisfies the following:

[0018] d(r)=d min +[(Φ c (ρ) mod 2π)·(d max -d min )] / 2π

[0019] Where, d min and d max These represent the minimum and maximum diameters of the nanopillars.

[0020] Preferably, all of the nanopillars are arranged in an array, and the diameter of the nanopillars decreases from the edge of the superlens towards the center.

[0021] Preferably, the focal point of the superlens is 1, or it is distributed in an array of 1*N or N*N, where N is a positive integer greater than 1.

[0022] Preferably, the optical path length of light rays passing through any nanopillar on the superlens to the i-th light spot is calculated, and the corresponding phase delay is obtained. The phase distribution of the nanopillars is optimized based on the phase superimposed at each target light spot. Based on the equivalent refractive index of the nanopillars, the phase is adjusted by geometric parameters until the focal point is obtained in a 1*N array distribution.

[0023] Preferably, when the focal points of the superlens are distributed in an N*N array, the incident light is decomposed into N... 2 The sub-beams are split by superimposing tilted phases to obtain the total phase. The mapping relationship between the nanopillar diameter d and the phase delay Φ is established. The relationship between the phase distribution and the corresponding nanopillar diameter distribution is simulated to obtain the nanopillar distribution.

[0024] Preferably, in S2, the sample surface data is the surface undulation data of the surface of the sample to be laser-processed.

[0025] A laser processing apparatus employing the aforementioned superlens-based laser processing method, the apparatus comprising:

[0026] A processing stage is equipped with a translation mechanism for placing the sample to be laser processed and for moving the sample on a horizontal plane.

[0027] A laser unit is used to emit laser light and shape the image;

[0028] A focusing module includes a height adjustment mechanism located above the translation mechanism and a superlens that is matched with the laser unit and is located on the height adjustment mechanism. The height adjustment mechanism is also equipped with a distance sensor.

[0029] A controller is provided to work in conjunction with the translation mechanism, laser unit, and focusing module.

[0030] This invention relates to a laser processing apparatus and method based on a superlens. A superlens is configured on the emission side of a laser processing head to scan the surface of the sample to be laser-processed, acquiring sample surface data. Based on the sample surface data, the height of the superlens corresponding to the sample position is configured, and a processing laser is output. The processing laser, after being focused by the superlens, acts on the sample to form a modified layer. The apparatus uses a processing stage equipped with a translation mechanism to place the sample to be laser-processed, allowing the sample to move on a horizontal plane. A laser unit emits and shapes the laser. A focusing module equipped with a superlens works in conjunction with the translation mechanism and the laser unit, and is controlled by a controller.

[0031] The beneficial effects of this invention are as follows:

[0032] (1) Using a high thermal conductivity and thin superlens as the laser processing lens, its characteristics are fully utilized to obtain a good heat dissipation effect, reduce the focus drift caused by heat accumulation, and the laser beam focus can still remain on the same plane after long-term operation, ensuring the formation of a modified layer with consistent depth.

[0033] (2) A good monochromatic laser focusing effect can be achieved by using a single superlens, and the overall device is lighter and more portable;

[0034] (3) After the processing laser is focused by the super lens, spherical aberration correction in the optical axis direction and multi-spot output of the laser beam can be achieved. The former suppresses the extension of the modified part in the optical axis direction during the laser stripping of silicon carbide ingots, thereby reducing the material loss of laser stripping and improving the surface roughness of the sample after stripping. The latter improves the processing efficiency. Attached Figure Description

[0035] Figure 1 This is a flowchart of the method of the present invention;

[0036] Figure 2 This is a schematic diagram of the superlens structure in this invention;

[0037] Figure 3 The diagrams are for focusing purposes, where (a) is a schematic diagram of focusing with a conventional lens and (b) is a schematic diagram of spherical aberration elimination using a superlens.

[0038] Figure 4 A schematic diagram illustrating the mapping between the diameter d of a nanopillar and the phase delay Φ under aberration elimination;

[0039] Figure 5 This is a schematic diagram of the multi-spot processing in this invention;

[0040] Figure 6 This is a schematic diagram of the optical path of light reaching the i-th light spot for a nanopillar with coordinates (x,y) on a superlens.

[0041] Figure 7The diagram shows the mapping between the nanopillar diameter d and the phase delay Φ when there are 1*N light spot outputs. In the figure, (a) is the phase distribution and (b) is the corresponding nanopillar diameter distribution.

[0042] Figure 8 The diagram shows the mapping between the diameter d of the nanopillars and the phase delay Φ when N*N light spot output is shown. In the figure, (a) shows the distribution of nanopillars, with nanopillars in the black part and no nanopillar structure in the white part, and (b) shows the corresponding distribution of nanopillar diameters.

[0043] Figure 9 This is a schematic diagram of the device structure of the present invention. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0045] This invention relates to a laser processing method based on a superlens, the method comprising the following steps:

[0046] (1) Configure superlens 1 and place it on the emission side of the laser processing head;

[0047] (2) Scan the surface of the sample 2 to be laser processed and obtain the surface data of sample 2;

[0048] (3) Configure the height of the superlens 1 corresponding to the position of sample 2 based on the surface data of sample 2;

[0049] (4) Output processing laser 3. After being focused by superlens 1, the processing laser 3 acts on sample 2 to form a modified layer.

[0050] The technical concept of this invention is as follows: before laser processing, a distance sensor at a certain height scans the surface of sample 2 to obtain data on the surface undulations of sample 2 and generate a height distribution map of sample 2. Then, utilizing the subwavelength structure design and phase modulation capability of the superlens 1, the processing laser 3, after being focused by the superlens 1, can achieve spherical aberration correction in the optical axis direction and multi-spot output of the laser beam. In conjunction with the processing stage 4, the sample 2 moves along a preset route. At the same time, the height adjustment mechanism 5 dynamically adjusts the processing distance based on the height distribution map of sample 2, ensuring that the modulated laser beam can be accurately focused on the same processing depth of sample 2 at different surface heights, forming uniformly distributed modified particles inside sample 2, and finally forming a highly uniform and stable processing modified layer inside sample 2.

[0051] The steps are described in detail below with reference to the embodiments.

[0052] (1) Configure superlens 1 and place it on the emission side of the laser processing head;

[0053] First, the structure of the superlens 1 is a matrix material on which a number of nanopillars 6 are distributed. Generally speaking, the nanopillars 6 are arranged in an array.

[0054] Therefore, let the distance from the location of nanopillar 6 to the center of superlens 1 be r. According to the principle of optical path difference compensation, the phase distribution of the ideal lens is as follows:

[0055]

[0056] Where λ is the wavelength of the incident light, and r is the distance from the location of each nanopillar 6 of the superlens 1 to the center of the superlens 1. Focal length;

[0057] However, when light is focused from a medium with a refractive index of n2 (such as air) into sample 2 with a refractive index of n3, the refraction of the light at the interface will cause spherical aberration at the focal point, which in turn affects the processing depth d. nom At this point, spherical aberration will cause phase error, satisfying the condition that...

[0058]

[0059] Where ρ is the normalized radius of the emitted laser, and d nom n1 is the depth inside the material to be processed, n2=1 is the air refractive index, n3 is the refractive index of the material to be processed, and NA is the numerical aperture of the superlens 1.

[0060] Based on this, a phase representation of the superlens 1 plane that eliminates spherical aberration is established.

[0061]

[0062]

[0063] Where ρ is the normalized radius of the emitted laser light, λ is the wavelength of the incident light, and r is the distance from the location of each nanopillar 6 of the superlens 1 to the center of the superlens 1. Focal length n is the processing depth of the laser-processed sample 2, n3 is the refractive index of the laser-processed sample 2, NA is the numerical aperture of the superlens 1, and n2 is the air refractive index.

[0064] Furthermore, each nanopillar 6 on the superlens 1 introduces a phase delay. The equivalent refractive index of this nanopillar 6 The existing relationship satisfies,

[0065]

[0066] in, It is the equivalent refractive index of nanopillar 6. It is the refractive index of substrate material 7. It is the height of nanopillar 6;

[0067] When the nanopillar 6 material is embedded in the substrate material 7, according to the Maxwell-Garnett theory, its equivalent refractive index is... satisfy,

[0068]

[0069] Here, n1 is the refractive index of the nanopillar 6 material, and p is the volume fraction of the nanopillar 6 material, which can be expressed as p = πd. 2 / 4a 2 Where a is the lattice constant; therefore, the equivalent refractive index of nanopillar 6 is... Related to the diameter d of the nanopillar 6, as the radius of the nanopillar 6 gradually increases from a small value, such as from 80 nm in the central region to 400 nm at the edge, its equivalent refractive index will gradually increase, thereby achieving fine control of the phase of light from the center to the edge of the superlens 1.

[0070] Therefore, the phase distribution is adjusted based on the diameter of each nanopillar 6.

[0071] like Figure 2 As shown, in the processing of silicon carbide ingots, a laser with a wavelength of 1064 nm is selected as the processing light source, the processing depth is 0.5 mm, and the numerical aperture NA is assumed to be 0.56. Silicon carbide (SiC, refractive index n1≈2.58@1064nm) is selected as the nanopillar 6 material and the substrate material 7. The height of the nanopillar 6 is h=300 nm, and the nanopillars 6 are periodically arranged with a spacing of lp=500 nm. The superlens 1 has a diameter of 5 mm and a focal length of 1 mm. The surface of the superlens 1 is divided into multiple micro-regions, each containing one nanopillar 6. According to the phase distribution... The diameter of each nanopillar r satisfies,

[0072] d(r)=d min +[(Φ c (ρ) mod 2π)·(d max -d min )] / 2π

[0073] Where, d min and d max These represent the minimum and maximum diameters of nanopillar 6.

[0074] The relationship between the diameter d and phase of the nanopillar 6 was established using simulation software. The mapping relationship yields the following simulation results: Figure 4As shown. In practical applications, considering the limitations of the processing technology, the calculated theoretical diameter of the nanopillar 6 is discretized. For example, the height of the nanopillar 6 is divided into 8 discrete levels. Based on the theoretical height calculated at each position on the superlens 1, the nanopillars 6 with the closest discrete height level are selected and arranged to approximate the required continuous phase distribution. Table 1 shows the correspondence between the diameter d of the nanopillar 6 and the phase when spherical aberration is eliminated;

[0075] Table 1. Correspondence between diameter d and phase of nanopillar 6 when spherical aberration is eliminated (discrete values).

[0076] phase Nanopillar diameter (nm) 0 60 0.25π 67 0.5π 76 0.75π 84 π 93 1.25π 102 1.5π 112 1.75π 123

[0077] It can be seen that when the diameter of the nanopillar 6 in the central region is 60 nm, the corresponding phase distribution Φ=0; as it moves closer to the edge, the radius gradually increases, and the diameter of the nanopillar 6 at the edge of the superlens 1 is about 120 nm, corresponding to the phase distribution Φ=2π.

[0078] That is, all the nanopillars 6 are arrayed, and the diameter of the nanopillars 6 decreases from the edge of the superlens 1 towards the center;

[0079] This gradient design precisely compensates for the phase of light, thereby achieving spherical aberration correction.

[0080] In this embodiment, the thermal conductivity of silicon carbide is fully utilized to significantly reduce the impact of thermal deformation. However, in practical applications, the selection of nanopillars 6 and substrate material 7 is not limited to silicon carbide. Other materials, including but not limited to diamond, barium metaborate, titanium dioxide, fused silica, etc., can be used to fabricate the superlens 1.

[0081] While correcting spherical aberration, in order to achieve multi-point output (improving processing efficiency), the superlens 1 needs to introduce a specific phase distribution for light rays at different positions, so that the light rays interfere with each other to form a focal point when they propagate to a specific position; therefore, further, the focal point of the superlens 1 is 1, or it is distributed in an array of 1*N or N*N, where N is a positive integer greater than 1.

[0082] The previous section discussed an embodiment where the focal point of the superlens 1 is 1. The following section discusses two other embodiments.

[0083] (i) Calculate the optical path of the light rays after passing through any nanopillar 6 on the superlens 1 to reach the i-th light spot, and obtain the corresponding phase delay. Optimize the phase distribution of the nanopillar 6 based on the superimposed phase at each target light spot. Based on the equivalent refractive index of the nanopillar 6, adjust the phase through geometric parameters until the focal point is obtained in an array distribution of 1*N.

[0084] Assume that the plane of superlens 1 is the xy plane, with its central origin at (0,0), and generate N focal points (y,y) side by side. iTaking (e.g., =0) as an example (one line), the x-coordinate of the i-th light point can be expressed as,

[0085] x i =[i-(N+1) / 2]d

[0086] Where i = 1, 2, 3, ..., N, and N is the number of light spots;

[0087] For the nanopillar 6 with coordinates (x, y) on the superlens 1, the optical path length of the light ray reaching the i-th light spot is L. i (x, y) satisfies

[0088]

[0089] The phase delay Φ required for light to reach the i-th spot i (x,y) satisfies,

[0090]

[0091] To simultaneously form N side-by-side light spots, the final equivalent refractive index of nanopillar 6 needs to be comprehensively considered. The phase contribution of each light spot is synthesized through complex superposition (coherent superposition), expressed as:

[0092]

[0093] in, It is the refractive index of substrate material 7. λ is the height of nanopillar 6, and λ is the wavelength of the incident light. Let be the equivalent refractive index contribution of the nanopillar 6 with coordinates (x, y) to the i-th light spot. The amplitude weight of the i-th light point is used; the phase contribution of each target point is superimposed to optimize the phase distribution ϕ(x,y) of the nanopillar 6; the equivalent refractive index n of the nanopillar 6 is designed. eff Phase can be controlled by geometric parameters;

[0094] In this embodiment, for laser lift-off of silicon carbide ingots, a 1064 nm laser is selected as the processing light source. Titanium dioxide (TiO2) is used as the material for the nanopillars 6 (refractive index n1≈2.3@1064 nm). The numerical aperture of the superlens 1 is set to 0.56, the height of the nanopillars 6 is fixed at h=600 nm, and the substrate material 7 is fused silica (refractive index n0=1.45@1064 nm). The nanopillars 6 are periodically arranged with a spacing lp of 300 nm (smaller than the wavelength to avoid higher-order diffraction). The diameter of the superlens 1 is set to 500 μm, the focal length to 100 μm, and two focal points are output. The phase distribution of a single lens is Φ1(x,y) and Φ2(x,y). After superposition, the phase distribution Φ(x,y) = Φ1(x,y) + Φ2(x,y) is obtained. The mapping relationship between the diameter d of the nanopillars 6 and the phase delay Φ is established using simulation software. Figure 7 As shown, by adjusting the diameter d of the nanopillar 6 (with discrete values ​​ranging from 100 nm to 400 nm), a phase coverage from 0 to 2π can be achieved. When a plane wave with a wavelength of 1064 nm is incident on the superlens 1, two focal points 100 μm apart can be formed on the focal plane.

[0095] (ii) When the focal points of superlens 1 are distributed in an N*N array, the incident light is decomposed into N... 2 The sub-beams are split by superimposing tilted phases to obtain the total phase. The mapping relationship between the diameter d of the nanopillar 6 and the phase delay Φ is established. The relationship between the phase distribution and the corresponding diameter distribution of the nanopillar 6 is simulated to obtain the nanopillar 6 distribution.

[0096] Furthermore, in order to achieve N*N focal points on the focal plane, the incident light is decomposed into N... 2 Each sub-beam is focused onto the target location.

[0097] An N*N lattice is split into beams by superimposing tilted phases, and the total phases are:

[0098]

[0099] Where, θ x =θ y =λ / d is the beam splitting angle between adjacent focal points, and D is the distance between focal plane points; lattice coordinates (x m ,y n )=(mD,nD), ;

[0100] In this embodiment, for laser lift-off of silicon carbide ingots, a 1064 nm laser is selected as the processing light source. TiO2 is used as the nanopillar 6 material (refractive index n1≈2.3@1064 nm), the numerical aperture of the superlens 1 is set to 0.56, the height of the nanopillar 6 is h=600 nm, and the substrate material 7 is fused silica (refractive index n0=1.45@1064 nm). The nanopillars 6 are periodically arranged with a spacing lp of 300 nm. Taking a 3*3 focal array as an example, assuming the diameter of the superlens 1 is 50 μm and the focal length is 100 μm, simulation software such as Python is used to establish the mapping relationship between the diameter d of the nanopillar 6 and the phase delay Φ, simulating the relationship between the phase distribution and the corresponding diameter distribution of the nanopillar 6, thus obtaining the distribution of the nanopillar 6. Figure 8 As shown, phase coverage from 0 to 2π is achieved by adjusting the diameter d of the nanopillar 6 (discretely ranging from 100 nm to 400 nm). When a plane wave with a wavelength of 1064 nm is incident on the superlens 1, a 3*3 focal array is formed on the focal plane with a focal spacing of 10 μm.

[0101] (2) Scan the surface of the sample 2 to be laser processed and obtain the surface data of sample 2;

[0102] The surface data of sample 2 is the surface undulation data of the surface of sample 2 to be laser processed.

[0103] The surface undulation data here is ultimately represented by the distance between the upper surface of sample 2 and superlens 1.

[0104] (3) Configure the height of the superlens 1 corresponding to the position of sample 2 based on the surface data of sample 2;

[0105] (4) Output processing laser 3. After being focused by superlens 1, the processing laser 3 acts on sample 2 to form a modified layer.

[0106] The present invention also relates to a laser processing apparatus employing the aforementioned superlens-based laser processing method, the apparatus comprising:

[0107] A processing stage 4 is equipped with a translation mechanism 8, which is used to place the sample 2 to be laser processed and to make the sample 2 move on a horizontal plane.

[0108] A laser unit is used to emit laser light and shape the image;

[0109] A focusing module includes a height adjustment mechanism 5 located above a translation mechanism 8 and a superlens 1 that is matched with a laser unit and is located on the height adjustment mechanism 5. The height adjustment mechanism 5 is also equipped with a distance sensor 9.

[0110] A controller 10 is provided to work in conjunction with the translation mechanism 8, the laser unit, and the focusing module.

[0111] In this invention, sample 2 is placed on processing stage 4, which is equipped with translation mechanism 8, allowing it to move horizontally along a preset fixed path. Therefore, distance sensor 9 on height adjustment mechanism 5 is generally located at the starting end facing processing stage 4. This allows for real-time acquisition of sample 2's surface height data during its movement, transmitting the data to controller 10 to form a surface height distribution map of sample 2. Subsequently, the height adjustment mechanism 5 controls the superlens 1 on the height adjustment mechanism to adjust the height, and the output processing laser 3, after being focused by the superlens 1, acts on sample 2 to form a modified layer. The height adjustment of height adjustment mechanism 5 is easily understood by those skilled in the art and can be achieved through the cooperation of a lead screw and nut pair with a motor or other methods, including but not limited to cylinder control.

[0112] In the specific implementation process, the laser unit includes a laser generator 11, a first concave lens 12, a first convex lens 13, and a first reflector 14 arranged in sequence. The emitted laser 3 of a specific wavelength passes through the first concave lens 12, the first convex lens 13, and the first reflector 14 to the superlens 1 and is focused to the preset depth of the sample 2 to form a modified quality. The first concave lens 12 and the first convex lens 13 are combined to realize laser beam shaping, expand the laser beam spot diameter, make the spot energy distribution more uniform, reduce hot spots and energy fluctuations, and the laser 3 after beam expansion is focused, the spot size at the focal point is smaller. The laser generator 11 here emits pulsed laser with a pulse width of 200 fs~10 ns, a wavelength of 500~1100 nm, a power of 5~200 W, and a repetition frequency of 5~500 kHz.

[0113] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0114] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A laser processing method based on a superlens, characterized in that: The method includes the following steps: S1 is equipped with a superlens and is located on the emission side of the laser processing head; Establish the phase representation of the superlens plane to eliminate spherical aberration. ， Where ρ is the normalized radius of the emitted laser light, λ is the wavelength of the incident light, and r is the distance from the location of each nanopillar of the superlens to the center of the superlens. Focal length n is the processing depth of the sample to be laser-processed, n3 is the refractive index of the sample to be laser-processed, NA is the numerical aperture of the superlens, and n2 is the refractive index of air. The phase distribution is adjusted by regulating the diameter of each nanopillar, and the diameter of each nanopillar of the superlens satisfies... d(r)=d min +[(Φ c (ρ) mod 2π)·(d max -d min )] / 2π Where, d min and d max These represent the minimum and maximum diameters of the nanopillars; All of the nanopillars are arrayed, and the diameter of the nanopillars decreases from the edge of the superlens towards the center; S2 scans the surface of the sample to be laser-processed to obtain sample surface data; S3 configures the height of the superlens corresponding to the sample location based on the sample surface data; The S4 outputs a processing laser, which is focused by a superlens and applied to the sample to form a modified layer.

2. The laser processing method based on a superlens according to claim 1, characterized in that: The focal point of the superlens is 1, or it can be distributed in an array of 1*N or N*N, where N is a positive integer greater than 1.

3. The laser processing method based on a superlens according to claim 2, characterized in that: Calculate the optical path length of light rays passing through any nanopillar on the superlens to the i-th light spot and obtain the corresponding phase delay. Optimize the phase distribution of the nanopillars based on the superimposed phase at each target light spot. Based on the equivalent refractive index of the nanopillars, adjust the phase through geometric parameters until the focal point is obtained in a 1*N array distribution.

4. The laser processing method based on a superlens according to claim 2, characterized in that: When the focal points of a superlens are distributed in an N*N array, the incident light is decomposed into N... 2 The sub-beams are split by superimposing tilted phases to obtain the total phase. The mapping relationship between the nanopillar diameter d and the phase delay Φ is established. The relationship between the phase distribution and the corresponding nanopillar diameter distribution is simulated to obtain the nanopillar distribution.

5. The laser processing method based on a superlens according to claim 1, characterized in that: In S2, the sample surface data is the surface undulation data of the surface of the sample to be laser-processed.

6. A laser processing apparatus employing the laser processing method based on a superlens as described in any one of claims 1 to 5, characterized in that: The device includes: A processing stage is equipped with a translation mechanism for placing the sample to be laser processed and for moving the sample on a horizontal plane. A laser unit is used to emit laser light and shape the image; A focusing module includes a height adjustment mechanism located above the translation mechanism and a superlens that is matched with the laser unit and is located on the height adjustment mechanism. The height adjustment mechanism is also equipped with a distance sensor. A controller is provided to work in conjunction with the translation mechanism, laser unit, and focusing module.

Images