Carving processing method and carving processing system based on vector pulse laser

Abstract

The invention discloses a carving machining method and system based on vector pulse laser, and belongs to the technical field of laser carving, the carving machining method based on the vector pulse laser comprises the steps that linear polarization femtosecond pulse laser is split into femtosecond pre-pulse laser and picosecond main pulse laser; adjusting the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser; combining the femtosecond pre-pulse laser and the picosecond main pulse laser after delay regulation and control; the femtosecond pre-pulse laser is converted into an angularly polarized femtosecond pre-pulse light beam, the picosecond main pulse laser is converted into a radially polarized picosecond main pulse light beam, and a double-pulse light beam combination of the angularly polarized femtosecond pre-pulse light beam and the radially polarized picosecond main pulse light beam is formed; and the to-be-machined workpiece is ablated and engraved through the double-pulse light beam combination. And by means of the synergistic effect of double pulses and precise time delay, the width and fusion damage of a heat affected zone are remarkably reduced, and high-precision and low-damage carving machining is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser engraving, and particularly relates to an engraving processing method and system based on a vector pulse laser. BACKGROUND

[0002] Traditional laser engraving usually adopts a single pulse laser, and has the problem that processing precision and efficiency are difficult to be considered. Femtosecond laser single pulse processing is affected by pulse throughput, resulting in low efficiency. In addition, a Gaussian beam based on linear polarization, due to the surface temperature gradient (high center temperature and low edge temperature) caused by uneven laser absorption in the processing process, the surface tension changes with the temperature (usually the higher the temperature, the smaller the surface tension), and the melt will flow from the low surface tension area (center) to the high surface tension area (edge), forming strong convection. This convection will take away the material in the center, causing the center to be concave, and push part of the material to the edge to solidify, and the microfluidic motion of this molten layer will form uneven surface topography.

[0003] Therefore, the femtosecond laser has small heat influence but low energy density, and the engraving efficiency is not high, it is difficult to quickly remove a large amount of material, the picosecond laser has relatively high energy and relatively good engraving efficiency, but the heat affected zone is large, which easily causes thermal damage, melting, cracking and other problems of the material, and the processing surface roughness is large, which affects the engraving quality. SUMMARY

[0004] The application aims to provide an engraving processing method and system based on a vector pulse laser, which at least solves the technical problems that the femtosecond laser has low engraving efficiency, the picosecond laser has a large heat affected zone, and the engraving efficiency and quality cannot be considered at the same time.

[0005] In order to solve the above technical problems, the application is implemented as follows:

[0006] In a first aspect, the application embodiment provides an engraving processing method based on a vector pulse laser, comprising: splitting a linearly polarized femtosecond pulse laser into a first femtosecond pulse laser and a second femtosecond pulse laser; determining the first femtosecond pulse laser as a femtosecond pre-pulse laser, and expanding the second femtosecond pulse laser into a picosecond main pulse laser; adjusting the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser; combining the femtosecond pre-pulse laser and the picosecond main pulse laser after time delay regulation; converting the femtosecond pre-pulse laser into an angularly polarized femtosecond pre-pulse beam and the picosecond main pulse laser into a radially polarized picosecond main pulse beam, to form a double-pulse beam combination of the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam; and ablation engraving a workpiece to be processed by using the double-pulse beam combination.

[0007] According to the vector pulse laser based engraving method provided in the application, first, linearly polarized femtosecond pulse laser is split into first femtosecond pulse laser and second femtosecond pulse laser, that is, one pulse laser beam is split into two pulse laser beams, the first femtosecond pulse laser is used as a pre-pulse laser, and the second femtosecond pulse laser is stretched to convert the second femtosecond pulse laser into a picosecond main pulse laser. Then, the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser is adjusted. The pulse time delay is the time difference between the two laser beams reaching the workpiece. By adjusting the pulse time delay, the spatio-temporal overlap of the two pulse laser beams in the material can be accurately controlled. When the pre-pulse reaches the workpiece slightly earlier than the main pulse, the femtosecond laser with smaller energy can be used to form a modified layer on the surface of the material, so that the energy coupling of the main pulse laser is more efficient, the energy deposition of the picosecond laser is suppressed, thereby reducing the width of the heat-affected zone and the deformation degree of the heat-affected zone.

[0008] After adjusting the pulse time delay, the pulse laser is converted into a vector pulse laser. Specifically, the femtosecond pre-pulse laser is converted into an angularly polarized femtosecond pre-pulse beam, the picosecond main pulse laser is converted into a radially polarized picosecond main pulse beam, and a double-pulse beam combination of the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam is formed. Then, the double-pulse beam combination is used to ablate and engrave the workpiece to be processed. Therefore, the workpiece is engraved by using the double-pulse vector laser. Compared with the traditional non-vector laser (such as linearly polarized laser or circularly polarized laser), the angularly polarized femtosecond pre-pulse beam excites a ring-shaped electric field around the center on the surface of the workpiece, which can uniformly soften and activate the surface layer of the material, suppress local overheating and melting, and significantly reduce the width of the heat-affected zone and the risk of cracking. The radially polarized picosecond main pulse beam can form a strong electric field converging along the radial direction at the focal point, which not only significantly improves the material removal rate, but also greatly reduces burrs and round corners, and is particularly suitable for clear forming of fine identification and fine edge structure. It can be seen that the linearly polarized femtosecond pulse laser is converted into the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam, and the synergistic effect of the double pulse and the precise time delay are used, which significantly reduces the width of the heat-affected zone and the melting damage, improves the material surface removal efficiency and edge quality, and thus realizes high-precision and low-damage engraving processing.

[0009] In some embodiments, the step of ablation and engraving the workpiece to be processed by using the double-pulse beam combination includes: the angularly polarized femtosecond pre-pulse beam pre-processes the workpiece to be processed to form a processing improvement layer; and the radially polarized picosecond main pulse beam performs secondary etching processing on the processing improvement layer; wherein the pulse time delay of the pre-processing and the secondary etching processing is set to 1 ps to 100 ps, and the pulse time delay is the time difference between the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam reaching the workpiece to be processed.

[0010] In this embodiment, the angularly polarized femtosecond prepulse beam and the radially polarized picosecond main pulse beam are time-domainally registered with a pulse time delay of 1 ps to 100 ps. The angularly polarized femtosecond prepulse beam first forms a modified layer on the material surface which is more easily absorbed by energy, and then the radially polarized picosecond main pulse beam realizes efficient and directional secondary material removal under the action of a radially converging strong electric field. That is, the angularly polarized femtosecond prepulse beam pre-processes the workpiece to be processed, activates the surface material of the workpiece, not only improves the material removal efficiency, but also suppresses the generation of micro-cracks, at the same time, the width of the heat-affected zone on the workpiece is narrower, the edge transition is smoother, the surface roughness is lower, and the quality of laser engraving is improved.

[0011] In some embodiments, optionally, the step of forming a processing-improved layer by the angularly polarized femtosecond prepulse beam pre-processing the workpiece to be processed, includes: the angularly polarized femtosecond prepulse beam forms a ring-shaped electric field on the surface of the workpiece to be processed; the ring-shaped electric field excites the electronic active state of the material surface layer and excites the material surface layer into plasma; and the angularly polarized femtosecond prepulse beam heats the plasma to the melting point of the material to form a processing-improved layer.

[0012] In this embodiment, the angularly polarized femtosecond prepulse beam can form a strong ring-shaped electric field on the surface of the workpiece, but the electric field strength in the axial direction is almost zero. The ring-shaped electric field can produce a uniform ring-shaped energy distribution on the metal surface, avoiding excessive heating in the central region. Secondly, the angularly polarized femtosecond prepulse beam exhibits significant waveguide effect in deep hole processing, that is, when the hole depth reaches a certain degree, most of the angularly polarized light is guided to the center of the ring-shaped structure, thereby improving the drilling efficiency.

[0013] At the same time, the angularly polarized femtosecond prepulse beam can induce the formation of a periodic electronic distribution on the surface of the workpiece, which provides an "energy coupling channel" for the energy coupling of the subsequent radially polarized light, so that energy can be more effectively deposited in the processing area. Secondly, the angularly polarized femtosecond prepulse beam can selectively excite specific plasma modes on the surface of the metal, forming a surface structure with a specific period and orientation, which reduces the energy threshold of subsequent processing. In addition, the angularly polarized light beam can also improve the processing performance of the material through the thermal softening effect, which can raise the temperature of the metal surface to a temperature close to the melting point, reduce the yield strength and viscosity of the material, that is, form a uniform modified layer on the material surface, so that the secondary etching can more effectively remove the material, reduce the required energy input in the subsequent process, and significantly reduce the ablation threshold required by the subsequent main pulse.

[0014] In some embodiments, optionally, the step of converting the femtosecond prepulse laser into an angularly polarized femtosecond prepulse laser beam, converting the picosecond main pulse laser into a radially polarized picosecond main pulse laser beam, and forming a dual-pulse beam combination of the angularly polarized femtosecond prepulse laser beam and the radially polarized picosecond main pulse laser beam comprises: adjusting a reference axis of the vortex wave plate so that the polarization direction of the femtosecond prepulse laser is perpendicular to the reference axis and the polarization direction of the picosecond main pulse laser is parallel to the reference axis; the femtosecond prepulse laser passing through the vortex wave plate is converted into an angularly polarized femtosecond prepulse laser beam, and the picosecond main pulse laser passing through the vortex wave plate is converted into a radially polarized picosecond main pulse laser beam, forming a dual-pulse beam combination; wherein the angularly polarized femtosecond prepulse laser beam can excite radial surface structures along the material surface, and the radially polarized picosecond main pulse laser beam can excite concentric circular surface structures around the material center.

[0015] In this embodiment, the femtosecond prepulse laser is modulated into an angularly polarized beam by a vortex wave plate, which can preferentially excite radial surface microstructures on the material surface, providing directional guidance for subsequent processing. The picosecond main pulse laser is converted into a radially polarized beam, which induces the formation of fine concentric circular structures centered on the material, thereby cooperating with the radial structures formed by the prepulse to significantly improve the controllability, uniformity and patterning quality of the workpiece surface structure, ensuring the engraving quality. In addition, the interval between the femtosecond prepulse laser and the picosecond main pulse laser is very short, and before the synthesis of the beam, the angles of the two lasers are adjusted to ensure that the polarization direction of the femtosecond prepulse laser is perpendicular to the reference axis and the polarization direction of the picosecond main pulse laser is parallel to the reference axis after entering the vortex wave plate.

[0016] In some embodiments, optionally, the step of adjusting the pulse time delay between the femtosecond prepulse laser and the picosecond main pulse laser comprises: collecting the plasma spectrum of the workpiece to be processed at the first time after the femtosecond prepulse laser irradiates the workpiece to be processed; extracting the intensity values of two preset wavelengths from the plasma spectrum and calculating the characteristic intensity ratio; when the characteristic intensity falls within the delay threshold range, the picosecond main pulse laser is triggered, and the trigger time difference between the femtosecond prepulse laser and the picosecond main pulse laser is determined as the pulse time delay; when the characteristic intensity does not fall within the delay threshold range, the first time is re-determined until the pulse time delay is determined.

[0017] In this embodiment, the plasma emission spectrum generated by the femtosecond laser is collected in real time by the spectrometer, and two preset characteristic spectral lines with clear physical meaning are accurately extracted therefrom, for example, for copper material, the peak intensity values at wavelengths of 521.8 nm and 510.5 nm are extracted, and the characteristic intensity ratio of the two intensity values is calculated, and the delay threshold range is greater than or equal to 1.8 and less than or equal to 2.2. The characteristic intensity ratio directly reflects the temperature and composition of the plasma, accurately characterizes the phase change state of the material under the action of the femtosecond pre-pulse laser, and determines that the surface of the workpiece to be processed is in a solid state, a molten state, or a gaseous state. Among them, if the characteristic intensity ratio falls within the delay threshold range, it is determined that the surface of the workpiece is in a molten state; if the characteristic intensity ratio is less than the lower limit value of the delay threshold range, the surface of the workpiece is in a solid state, and the time for collecting the plasma spectrum needs to be increased; if the characteristic intensity ratio is greater than the upper limit value of the delay threshold range, the time for collecting the plasma spectrum needs to be reduced. At the same time, the time difference from the start of the femtosecond pre-pulse laser irradiation to the first moment is the pulse time delay, that is, under the pulse time delay, the femtosecond pre-pulse laser can heat the surface of the workpiece to be processed to a molten state, which is beneficial to the efficient and high-quality secondary ablation of the picosecond main pulse laser.

[0018] In some embodiments, optionally, the step of extracting the intensity values of the two preset wavelengths from the plasma spectrum and calculating the characteristic intensity ratio includes: obtaining the material of the workpiece to be processed, determining the preset wavelength according to the material of the workpiece to be processed; determining the first intensity value and the second intensity value corresponding to the preset wavelength according to the plasma spectrum; determining the characteristic intensity ratio according to the ratio of the second intensity value to the first intensity value; wherein the first intensity value is less than the second intensity value.

[0019] In this embodiment, the preset wavelength and the delay threshold range are determined according to the material of the workpiece to be processed, that is, the preset wavelength and the delay threshold range of each material are different, the characteristic intensity ratio is determined by calculating the ratio of the second intensity value to the first intensity value, and the characteristic intensity ratio reflects the phase change state of the material. It can be seen that the present application solves the problem that the traditional method cannot adapt to multiple materials due to the inability to determine the pulse time delay. At the same time, the present application provides reliable data support for subsequent real-time and accurate determination of the pulse time delay, thereby laying a solid foundation for finally obtaining a high-quality processing effect with sharp edges and a very small heat-affected zone.

[0020] In a second aspect, the embodiments of the present application propose a vector pulse laser-based engraving processing system for implementing the vector pulse laser-based engraving processing method proposed in the first aspect.

[0021] The vector-pulse laser-based engraving system provided in the application is used to realize the vector-pulse laser-based engraving method proposed in the first aspect, and thus has all the beneficial effects of the vector-pulse laser-based engraving method proposed in the first aspect, which will not be repeated here.

[0022] In some embodiments, the vector-pulse laser-based engraving system comprises: a femtosecond laser light source module for emitting linearly polarized femtosecond pulse laser; a workbench for placing a workpiece to be processed; a beam splitting module arranged between the femtosecond laser light source module and the workbench, for splitting the linearly polarized femtosecond pulse laser into a first femtosecond pulse laser and a second femtosecond pulse laser, and taking the first femtosecond pulse laser as a femtosecond pre-pulse laser; a pulse width expansion module arranged between the beam splitting module and the workbench, for expanding the second femtosecond pulse laser into a picosecond main pulse laser; a time delay control module arranged between the beam splitting module and the workbench, for adjusting the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser; a beam combining module arranged between the time delay control module and the workbench, for combining the time-delayed femtosecond pre-pulse laser and the picosecond main pulse laser; and a vector conversion module arranged between the beam combining module and the workbench, for converting the femtosecond pre-pulse laser into an angularly polarized femtosecond pre-pulse laser beam and the picosecond main pulse laser into a radially polarized picosecond main pulse laser beam, to form a dual-pulse laser beam combination of the angularly polarized femtosecond pre-pulse laser beam and the radially polarized picosecond main pulse laser beam.

[0023] According to the vector pulse laser based engraving processing system provided in the application, the system comprises a femtosecond laser light source module, a workbench, a beam splitting module, a pulse width expansion module, a time delay control module, a beam combining module and a vector conversion module. The femtosecond laser light source module is used to emit linearly polarized femtosecond pulse laser, and the workbench is used to place a workpiece to be processed. After the linearly polarized femtosecond pulse laser passes through the beam splitting module, the linearly polarized femtosecond pulse laser is split into first femtosecond pulse laser and second femtosecond pulse laser, and the first femtosecond pulse laser is directly used as femtosecond pre-pulse laser. Then the second femtosecond pulse laser is expanded into picosecond main pulse laser through the pulse width expansion module, the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser is adjusted through the time delay control module, the femtosecond pre-pulse laser and the picosecond main pulse laser after the time delay control are combined through the beam combining module, finally the femtosecond pre-pulse laser is converted into angularly polarized femtosecond pre-pulse beam through the vector conversion module, and the picosecond main pulse laser is converted into radially polarized picosecond main pulse beam through the vector conversion module, thereby forming a double-pulse beam combination of the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam. Then the double-pulse beam combination is used to ablate and engrave the workpiece to be processed. Therefore, the workpiece is engraved by using the double-pulse vector laser, compared with the traditional non-vector laser (such as linearly polarized laser or circularly polarized laser), the angularly polarized femtosecond pre-pulse beam can excite a ring-shaped electric field around the center on the surface of the workpiece, can uniformly soften and activate the material surface layer, can inhibit local overheating and melting, and can significantly reduce the width of the heat affected zone and the risk of cracking; the radially polarized picosecond main pulse beam can form a strong electric field along the radial direction at the focal point, can significantly improve the material removal rate, and can greatly reduce burrs and round corners, and is particularly suitable for clear forming of fine identification and fine edge structure. It can be seen that the linearly polarized femtosecond pulse laser is converted into the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam, the synergistic effect and the precise time delay of the double pulse are utilized, the width of the heat affected zone and the melting damage are significantly reduced, the material surface removal efficiency and the edge quality are improved, and high-precision and low-damage engraving processing is realized.

[0024] In some embodiments, optionally, the vector pulse laser based engraving processing system further comprises: a beam expansion module arranged between the beam combining module and the vector conversion module, used to expand the beam diameter of the double-pulse beam combination; a motion control module arranged between the vector conversion module and the workbench, used to move the double-pulse beam combination to ablate and engrave the workpiece to be processed, the motion control module comprises two scanning galvanometers, the reflection direction of the double-pulse beam is changed by adjusting the angles of the two scanning galvanometers.

[0025] In this embodiment, the vector-pulse laser-based engraving processing system further comprises a beam expansion module and a motion control module. The beam expansion module can expand the injection diameter of the combined dual-pulse beam and improve the peak power density at the focal point and the processing precision. The motion control module can quickly change the reflection direction of the beam, significantly improving the engraving efficiency, and is particularly suitable for complex patterns and large-area uniform processing. Two scanning galvanometers rotate around their respective rotation axes to change the reflection direction according to the reflection law of the beam. One scanning galvanometer controls the deflection angle of the beam in the horizontal direction, and the other scanning galvanometer controls the deflection angle of the beam in the vertical direction, so that the landing point of the dual-pulse beam on the working plane moves quickly and continuously along the set path, thereby realizing high-speed and high-precision ablation engraving.

[0026] In some embodiments, optionally, the time delay control module comprises: a first adjusting stage arranged between the beam splitting module and the beam combining module, for changing the optical path of the first femtosecond pulse laser; and a second adjusting stage arranged between the beam splitting module and the beam combining module, for changing the optical path of the second femtosecond pulse laser.

[0027] In this embodiment, by acting on the first femtosecond pulse laser and the second femtosecond pulse laser through the first adjusting stage and the second adjusting stage, respectively, changing the geometric path length of any one adjusting stage can adjust the arrival time of the beam, and simultaneously changing the geometric path length of the two adjusting stages can more quickly adjust the optical path difference between the two pulse lasers, and can also increase the adjustment range of the optical path difference to perform double-laser etching on different types of materials.

[0028] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above and / or additional aspects and advantages of the application will become apparent and be readily appreciated from the following description, including the appended drawings, wherein:

[0030] Figure 1 A flowchart of a vector-pulse laser-based engraving processing method is shown;

[0031] Figure 2 A flowchart of another vector-pulse laser-based engraving processing method is shown;

[0032] Figure 3 A structural schematic diagram of a vector-pulse laser-based engraving processing system is shown.

[0033] In the drawings, Figure 3 The correspondence between the reference signs in the drawings and the component names is as follows:

[0034] 100 vector pulse laser based engraving processing system, 10 femtosecond laser light source module, 20 workbench, 30 beam splitting module, 40 pulse width expansion module, 50 delay control module, 52 first adjusting table, 54 second adjusting table, 60 beam combining module, 70 vector conversion module, 80 beam expander module, 90 motion control module, 2 refractive mirror, 4 concave mirror, 6 convex mirror, 8 half wave plate. DETAILED DESCRIPTION

[0035] Embodiments of the present application will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] The following will be described in detail Figures 1-3 The vector pulse laser based engraving processing method and processing system of the embodiments of the present application are described.

[0037] As Figure 1 shown, according to the vector pulse laser based engraving processing method proposed by the present application, comprising:

[0038] S101: splitting linearly polarized femtosecond pulse laser into first femtosecond pulse laser and second femtosecond pulse laser;

[0039] S102: determining the first femtosecond pulse laser as femtosecond pre-pulse laser, and expanding the second femtosecond pulse laser as picosecond main pulse laser;

[0040] S103: adjusting the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser;

[0041] S104: combining the femtosecond pre-pulse laser and the picosecond main pulse laser after delay control;

[0042] S105: converting the femtosecond pre-pulse laser into angularly polarized femtosecond pre-pulse beam, and converting the picosecond main pulse laser into radially polarized picosecond main pulse beam, forming a dual-pulse beam combination of angularly polarized femtosecond pre-pulse beam and radially polarized picosecond main pulse beam;

[0043] S106: ablation engraving of the workpiece to be processed by using the dual-pulse beam combination.

[0044] According to the vector pulse laser based engraving method provided in the application, first, linearly polarized femtosecond pulse laser is split into first femtosecond pulse laser and second femtosecond pulse laser, that is, one pulse laser beam is split into two pulse laser beams, the first femtosecond pulse laser is used as a pre-pulse laser, and the second femtosecond pulse laser is stretched to convert the second femtosecond pulse laser into a picosecond main pulse laser. Then, the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser is adjusted. The pulse time delay is the time difference between the two laser beams reaching the workpiece. By adjusting the pulse time delay, the spatio-temporal overlap of the two pulse laser beams in the material can be accurately controlled. When the pre-pulse reaches the workpiece slightly earlier than the main pulse, the femtosecond laser with smaller energy can be used to form a modified layer on the surface of the material, so that the energy coupling of the main pulse laser is more efficient, the energy deposition of the picosecond laser is suppressed, thereby reducing the width of the heat-affected zone and the deformation degree of the heat-affected zone.

[0045] After adjusting the pulse time delay, the pulse laser is converted into a vector pulse laser. Specifically, the femtosecond pre-pulse laser is converted into an angularly polarized femtosecond pre-pulse beam, the picosecond main pulse laser is converted into a radially polarized picosecond main pulse beam, and a double-pulse beam combination of the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam is formed. Then, the double-pulse beam combination is used to ablate and engrave the workpiece to be processed. Therefore, the workpiece is engraved by using the double-pulse vector laser. Compared with the traditional non-vector laser (such as linearly polarized laser or circularly polarized laser), the angularly polarized femtosecond pre-pulse beam excites a ring-shaped electric field around the center on the surface of the workpiece, which can uniformly soften and activate the surface layer of the material, suppress local overheating and melting, and significantly reduce the width of the heat-affected zone and the risk of cracking. The radially polarized picosecond main pulse beam can form a strong electric field converging along the radial direction at the focal point, which not only significantly improves the material removal rate, but also greatly reduces burrs and round corners, and is particularly suitable for clear forming of fine identification and fine edge structure. It can be seen that the linearly polarized femtosecond pulse laser is converted into the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam, and the synergistic effect of the double pulse and the precise time delay are used, which significantly reduces the width of the heat-affected zone and the melting damage, improves the material surface removal efficiency and edge quality, and thus realizes high-precision and low-damage engraving processing.

[0046] In some embodiments, the step of ablation and engraving the workpiece to be processed by using the double-pulse beam combination includes: the angularly polarized femtosecond pre-pulse beam pre-processes the workpiece to be processed to form a processing improvement layer; and the radially polarized picosecond main pulse beam performs secondary etching treatment on the processing improvement layer; wherein the pulse time delay of the pre-processing and the secondary etching treatment is set to 1 ps to 100 ps, and the pulse time delay is the time difference between the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam reaching the workpiece to be processed.

[0047] In this embodiment, the angularly polarized femtosecond prepulse beam and the radially polarized picosecond main pulse beam are time-domainally registered with a pulse time delay of 1 ps to 100 ps. The angularly polarized femtosecond prepulse beam first forms a modified layer on the material surface which is more easily absorbed by energy, and then the radially polarized picosecond main pulse beam realizes efficient and directional secondary material removal under the action of a radially converging strong electric field. That is, the angularly polarized femtosecond prepulse beam pre-processes the workpiece to be processed, activates the surface material of the workpiece, not only improves the material removal efficiency, but also suppresses the generation of micro-cracks, at the same time, the width of the heat-affected zone on the workpiece is narrower, the edge transition is smoother, the surface roughness is lower, and the quality of laser engraving is improved.

[0048] In some embodiments, optionally, the step of forming a processing-improved layer by the angularly polarized femtosecond prepulse beam pre-processing the workpiece to be processed includes: the angularly polarized femtosecond prepulse beam forms a ring-shaped electric field on the surface of the workpiece to be processed; the ring-shaped electric field excites the electronic active state of the material surface layer and excites the material surface layer into plasma; and the angularly polarized femtosecond prepulse beam heats the plasma to the melting point of the material to form a processing-improved layer.

[0049] In this embodiment, the angularly polarized femtosecond prepulse beam can form a strongly constrained ring-shaped electric field on the surface of the workpiece, but the electric field strength in the axial direction is almost zero. The ring-shaped electric field can produce a uniform ring-shaped energy distribution on the metal surface, avoiding excessive heating in the central region. Secondly, the angularly polarized femtosecond prepulse beam exhibits significant waveguide effect in deep hole processing, that is, when the hole depth reaches a certain degree, most of the angularly polarized light is guided to the center of the ring-shaped structure, thereby improving the drilling efficiency.

[0050] At the same time, the angularly polarized femtosecond prepulse beam can induce the formation of a periodic electronic distribution on the surface of the workpiece, which provides an "energy coupling channel" for the energy coupling of the subsequent radially polarized light, so that energy can be more effectively deposited in the processing area. Secondly, the angularly polarized femtosecond prepulse beam can selectively excite specific plasma modes on the surface of the metal, forming a surface structure with a specific period and orientation, which reduces the energy threshold of subsequent processing. In addition, the angularly polarized beam can also improve the processing performance of the material through the thermal softening effect, which can raise the temperature of the metal surface to a temperature close to the melting point, reduce the yield strength and viscosity of the material, that is, form a uniform modified layer on the surface of the material, so that the secondary etching can more effectively remove the material, reduce the required energy input in the subsequent process, and significantly reduce the ablation threshold required by the subsequent main pulse.

[0051] In some embodiments, optionally, the step of converting the femtosecond prepulse laser into an angularly polarized femtosecond prepulse laser beam, converting the picosecond main pulse laser into a radially polarized picosecond main pulse laser beam, and forming a dual-pulse beam combination of the angularly polarized femtosecond prepulse laser beam and the radially polarized picosecond main pulse laser beam comprises: adjusting a reference axis of the vortex wave plate so that the polarization direction of the femtosecond prepulse laser is perpendicular to the reference axis and the polarization direction of the picosecond main pulse laser is parallel to the reference axis; the femtosecond prepulse laser passing through the vortex wave plate is converted into an angularly polarized femtosecond prepulse laser beam, and the picosecond main pulse laser passing through the vortex wave plate is converted into a radially polarized picosecond main pulse laser beam, forming a dual-pulse beam combination; wherein the angularly polarized femtosecond prepulse laser beam can excite radial surface structures on the material surface, and the radially polarized picosecond main pulse laser beam can excite concentric circular surface structures around the material center.

[0052] In this embodiment, the femtosecond prepulse laser is modulated into an angularly polarized beam by a vortex wave plate, which can preferentially excite radial surface microstructures on the material surface, providing directional guidance for subsequent processing. The picosecond main pulse laser is converted into a radially polarized beam, which induces the formation of fine concentric circular structures centered on the material, thereby cooperating with the radial structures formed by the prepulse to significantly improve the controllability, uniformity and patterning quality of the workpiece surface structure, ensuring the engraving quality. In addition, the interval between the femtosecond prepulse laser and the picosecond main pulse laser is very short, and the angles of the two lasers are adjusted before the synthesis of the beam, so that the polarization direction of the femtosecond prepulse laser is perpendicular to the reference axis and the polarization direction of the picosecond main pulse laser is parallel to the reference axis after passing through the vortex wave plate.

[0053] In some embodiments, optionally, the step of adjusting the pulse time delay between the femtosecond prepulse laser and the picosecond main pulse laser comprises: collecting a plasma spectrum of the workpiece to be processed at a first time after the femtosecond prepulse laser irradiates the workpiece to be processed; extracting intensity values of two preset wavelengths from the plasma spectrum and calculating a characteristic intensity ratio; when the characteristic intensity falls within a delay threshold range, the picosecond main pulse laser is triggered, and the trigger time difference between the femtosecond prepulse laser and the picosecond main pulse laser is determined as the pulse time delay; when the characteristic intensity does not fall within the delay threshold range, the first time is re-determined until the pulse time delay is determined.

[0054] In this embodiment, the plasma emission spectrum generated by the femtosecond laser is collected in real time by the spectrometer, and two preset characteristic spectral lines with clear physical meaning are accurately extracted therefrom, for example, for copper material, the peak intensity values at wavelengths of 521.8 nm and 510.5 nm are extracted, and the characteristic intensity ratio of the two intensity values is calculated, and the delay threshold range is greater than or equal to 1.8 and less than or equal to 2.2. The characteristic intensity ratio directly reflects the temperature and composition of the plasma, accurately characterizes the phase change state of the material under the action of the femtosecond pre-pulse laser, and determines that the surface of the workpiece to be processed is in a solid state, a molten state, or a gaseous state. Among them, if the characteristic intensity ratio falls within the delay threshold range, it is determined that the surface of the workpiece is in a molten state; if the characteristic intensity ratio is less than the lower limit value of the delay threshold range, the surface of the workpiece is in a solid state, and the time for collecting the plasma spectrum needs to be increased; if the characteristic intensity ratio is greater than the upper limit value of the delay threshold range, the time for collecting the plasma spectrum needs to be reduced. At the same time, the time difference from the start of the femtosecond pre-pulse laser irradiation to the first moment is the pulse time delay, that is, under the pulse time delay, the femtosecond pre-pulse laser can heat the surface of the workpiece to be processed to a molten state, which is beneficial to the efficient and high-quality secondary ablation of the picosecond main pulse laser.

[0055] In some embodiments, optionally, the step of extracting the intensity values of the two preset wavelengths from the plasma spectrum and calculating the characteristic intensity ratio includes: obtaining the material of the workpiece to be processed, determining the preset wavelength according to the material of the workpiece to be processed; determining the first intensity value and the second intensity value corresponding to the preset wavelength according to the plasma spectrum; determining the characteristic intensity ratio according to the ratio of the second intensity value to the first intensity value; wherein the first intensity value is less than the second intensity value.

[0056] In this embodiment, the preset wavelength and the delay threshold range are determined according to the material of the workpiece to be processed, that is, the preset wavelength and the delay threshold range of each material are different. The characteristic intensity ratio is determined by calculating the ratio of the second intensity value to the first intensity value, and the characteristic intensity ratio reflects the phase change state of the material. It can be seen that the present application solves the problem that the traditional method cannot adapt to multiple materials due to the inability to determine the pulse time delay. At the same time, the present application provides reliable data support for subsequent real-time and accurate determination of the pulse time delay, thereby laying a solid foundation for finally obtaining a high-quality processing effect with sharp edges and a very small heat-affected zone.

[0057] As shown in Figure 2 Another vector pulse laser-based engraving processing method according to the present application includes:

[0058] S201: splitting a linearly polarized femtosecond pulse laser into a first femtosecond pulse laser and a second femtosecond pulse laser;

[0059] S202: Determine the first femtosecond pulse laser as a femtosecond pre-pulse laser, and expand the second femtosecond pulse laser into a picosecond main pulse laser;

[0060] S203: After the femtosecond pre-pulse laser irradiates the workpiece to be processed, the plasma spectrum of the workpiece to be processed at the first time is collected;

[0061] S204: Obtain the material of the workpiece to be processed, and determine the preset wavelength according to the material of the workpiece to be processed;

[0062] S205: Determine the first intensity value and the second intensity value corresponding to the preset wavelength according to the plasma spectrum;

[0063] S206: Determine the characteristic intensity ratio according to the ratio of the second intensity value to the first intensity value;

[0064] S207: When the characteristic intensity falls within the delay threshold range, the picosecond main pulse laser is triggered, and the trigger time difference of the femtosecond pre-pulse laser and the picosecond main pulse laser is determined as the pulse time delay. When the characteristic intensity does not fall within the delay threshold range, the first time is determined again until the pulse time delay is determined;

[0065] S208: Combine the femtosecond pre-pulse laser after time delay control and the picosecond main pulse laser;

[0066] S209: Adjust the reference axis of the vortex wave plate, so that the polarization direction of the femtosecond pre-pulse laser is perpendicular to the reference axis, and the polarization direction of the picosecond main pulse laser is parallel to the reference axis;

[0067] S210: The femtosecond pre-pulse laser passing through the vortex wave plate is converted into an angularly polarized femtosecond pre-pulse beam, and the picosecond main pulse laser passing through the vortex wave plate is converted into a radially polarized picosecond main pulse beam, forming a double-pulse beam combination;

[0068] S211: The angularly polarized femtosecond pre-pulse beam forms a ring-shaped electric field on the surface of the workpiece to be processed;

[0069] S212: The ring-shaped electric field excites the electronic activity state of the material surface layer, and excites the material surface layer into plasma;

[0070] S213: The angularly polarized femtosecond pre-pulse beam heats the plasma to the melting point of the material to form a processing improvement layer;

[0071] S214: The radially polarized picosecond main pulse beam performs secondary etching treatment on the processing improvement layer.

[0072] In a second aspect, the embodiments of the present application propose a vector pulse laser-based engraving processing system for realizing the vector pulse laser-based engraving processing method proposed in the first aspect.

[0073] The vector-pulse-laser-based engraving system provided in the present application is used to implement the vector-pulse-laser-based engraving method proposed in the first aspect, and thus has all the beneficial effects of the vector-pulse-laser-based engraving method proposed in the first aspect, which will not be repeated here.

[0074] In some embodiments, as shown in Figure 3 The vector-pulse-laser-based engraving system 100 includes a femtosecond laser light source module 10 for emitting linearly polarized femtosecond pulse laser light, a workbench 20 for placing a workpiece to be processed, a beam splitting module 30 arranged between the femtosecond laser light source module 10 and the workbench 20 for splitting the linearly polarized femtosecond pulse laser light into first femtosecond pulse laser light and second femtosecond pulse laser light, and taking the first femtosecond pulse laser light as femtosecond pre-pulse laser light, a pulse width expansion module 40 arranged between the beam splitting module 30 and the workbench 20 for expanding the second femtosecond pulse laser light into picosecond main pulse laser light, a time delay control module 50 arranged between the beam splitting module 30 and the workbench 20 for adjusting the pulse time delay between the femtosecond pre-pulse laser light and the picosecond main pulse laser light, a beam combining module 60 arranged between the time delay control module 50 and the workbench 20 for combining the femtosecond pre-pulse laser light and the picosecond main pulse laser light after time delay control, and a vector conversion module 70 arranged between the beam combining module 60 and the workbench 20 for converting the femtosecond pre-pulse laser light into angularly polarized femtosecond pre-pulse light beam and the picosecond main pulse laser light into radially polarized picosecond main pulse light beam, forming a dual-pulse light beam combination of angularly polarized femtosecond pre-pulse light beam and radially polarized picosecond main pulse light beam.

[0075] The vector pulse laser-based engraving system 100 provided in this application includes a femtosecond laser source module 10, a worktable 20, a beam splitting module 30, a pulse width broadening module 40, a delay control module 50, a beam combining module 60, and a vector conversion module 70. The femtosecond laser source module 10 emits linearly polarized femtosecond pulse lasers, the worktable 20 holds the workpiece to be processed, and the linearly polarized femtosecond pulse laser is split into a first femtosecond pulse laser and a second femtosecond pulse laser after passing through the beam splitting module 30. The first femtosecond pulse laser is directly used as a femtosecond pre-pulse laser. The second femtosecond laser pulse is then broadened into a picosecond main pulse using a pulse width broadening module 40. The pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser is adjusted using a delay control module 50. The delayed femtosecond pre-pulse laser and the picosecond main pulse laser are then combined using a beam combining module 60. Finally, a vector conversion module 70 converts the femtosecond pre-pulse laser into an angularly polarized femtosecond pre-pulse beam and the picosecond main pulse laser into a radially polarized picosecond main pulse beam, forming a dual-pulse beam combination of an angularly polarized femtosecond pre-pulse beam and a radially polarized picosecond main pulse beam. This dual-pulse beam combination is then used for ablation and engraving of the workpiece. Therefore, this application employs a dual-pulse vector laser for workpiece engraving. Compared to traditional non-vector lasers (such as linearly polarized or circularly polarized lasers), the angularly polarized femtosecond prepulse beam excites a ring-shaped electric field around the center of the workpiece surface. This uniformly softens and activates the material surface layer, suppresses local overheating and melting, and significantly reduces the width of the heat-affected zone and the risk of cracking. The radially polarized picosecond main pulse beam forms a strong electric field converging radially at the focal point, which not only significantly improves the material removal rate but also greatly reduces burrs and rounded corners, making it particularly suitable for the clear shaping of fine markings and delicate edge structures. Thus, this application converts a linearly polarized femtosecond pulse laser into an angularly polarized femtosecond prepulse beam and a radially polarized picosecond main pulse beam. By utilizing the synergistic effect of the dual pulses and precise time delay, it significantly reduces the width of the heat-affected zone and melting damage, improves the material surface removal efficiency and edge quality, thereby achieving high-precision, low-damage engraving processing. Figure 3 In the diagram, (a) represents the waveform of the femtosecond prepulse laser, (b) represents the waveform of the picosecond main pulse laser, and (c) represents the waveform of the combined double pulse laser.

[0076] In some embodiments, the vector-pulse laser-based engraving processing system 100 optionally further comprises: a beam expansion module 80 disposed between the beam combination module 60 and the vector conversion module 70, configured to expand the diameter of the combined dual-pulse light beam; and a motion control module 90 disposed between the vector conversion module 70 and the workbench 20, configured to move the combined dual-pulse light beam to ablate and engrave the workpiece to be processed. The motion control module 90 comprises two scanning galvanometers, and the reflection direction of the dual-pulse light beam is changed by adjusting the angles of the two scanning galvanometers.

[0077] In this embodiment, the vector-pulse laser-based engraving processing system 100 further comprises the beam expansion module 80 and the motion control module 90. The beam expansion module 80 is capable of expanding the diameter of the combined dual-pulse light beam, thereby improving the peak power density at the focal point and the processing precision. The motion control module 90 is capable of quickly changing the reflection direction of the light beam, thereby significantly improving the engraving efficiency, and is particularly suitable for complex patterns and large-area uniform processing. The two scanning galvanometers rotate around their respective rotation axes to change the reflection direction according to the law of reflection of light beams. One of the scanning galvanometers controls the deflection angle of the light beam in the horizontal direction, and the other scanning galvanometer controls the deflection angle of the light beam in the vertical direction. The landing point of the dual-pulse light beam on the working plane moves quickly and continuously along the set path, thereby achieving high-speed and high-precision ablation engraving.

[0078] In some embodiments, the delay control module 50 optionally comprises: a first adjustment stage 52 disposed between the beam splitting module 30 and the beam combination module 60, configured to change the optical path of the first femtosecond pulse laser; and a second adjustment stage 54 disposed between the beam splitting module 30 and the beam combination module 60, configured to change the optical path of the second femtosecond pulse laser.

[0079] In this embodiment, the first adjustment stage 52 and the second adjustment stage 54 act on the first femtosecond pulse laser and the second femtosecond pulse laser, respectively. Changing the geometric path length of any one adjustment stage can adjust the arrival time of the light beam, and changing the geometric path length of both adjustment stages can more quickly adjust the optical path difference between the two pulse lasers and increase the adjustment range of the optical path difference, thereby enabling double laser etching of different types of materials.

[0080] In one specific implementation, the present application provides a spatiotemporal control-based ultrafast laser engraving processing system. The laser engraving processing system of the present application mainly comprises a femtosecond laser light source module 10, a beam expansion and collimation module (including a refractive mirror 2, a concave mirror 4, and a convex mirror 6), a beam splitting module 30, an energy control module (a half-wave plate 8), a pulse width expansion module 40, a dual-pulse delay control module (a delay control module 50), a beam polarization shaping module (including a beam expansion module 80 and a vector conversion module 70), and a galvanometer motion control module (a motion control module 90).

[0081] Firstly, the femtosecond pulse beam emitted from the femtosecond laser source module 10 passes through the refractive mirror 2, the concave mirror 4 and the convex mirror 6 to perform beam spatial height and horizontal direction collimation and reduce the divergence of the beam in the system transmission process. Then, the expanded and collimated beam passes through the beam splitting module 30 and the half-wave plate 8, and the energy ratio of the two beams of orthogonally polarized sub-beams is controlled by rotating the half-wave plate 8 to change the energy of the preheating and main heating in the double-pulse processing process. Among them, the first femtosecond sub-beam passes through the first adjusting table 52 to control the optical path of the optical path, and the second femtosecond sub-beam enters the pulse width expansion module 40, and the femtosecond pulse is expanded into a picosecond pulse by adjusting the dispersion amount between the two gratings, and then the second sub-beam passes through the second adjusting table 54 to control the optical path of the optical path. The two sub-beams pass through the beam combining module 60 to perform beam combining, and the combined beam enters the beam expanding module 80 and the vector conversion module 70, and the reference axis of the vector conversion module 70 (vortex wave plate) is adjusted, when the sub-beam with linear polarization is parallel to the reference axis of the vortex wave plate, the output beam is converted into radial polarization. When the other beam of linearly polarized sub-beam is perpendicular to the reference axis of the vortex wave plate, the output beam is converted into angular polarization. Finally, the femtosecond pulse beam with angular polarization and the picosecond pulse beam with radial polarization enter the motion control module 90 for beam movement to perform pattern engraving.

[0082] The generated polarization state can be verified by analyzing the orientation of the laser-induced periodic surface structure generated on the metal surface under irradiation of different polarized light. The structure stripe generated by linear polarization is perpendicular to the polarization direction of the laser; the structure stripe generated by radial polarization is concentric circular; the structure stripe generated by angular polarization is radial.

[0083] The engraving processing system 100 based on vector pulse laser divides the single pulse beam into femtosecond and picosecond double-pulse beams, and adjusts the time delay between the two pulses. This time-based control can make the femtosecond laser play a preheating role in exciting nonlinear absorption on the material surface, and the picosecond laser can perform sufficient ablation for main heating, which greatly improves the engraving efficiency.

[0084] Converting linearly polarized Gaussian light into cylindrical vector light with vector polarization can adjust the uniformity of the polarization distribution, suppress the formation of material bottom burrs and conical molten column caused by microfluid motion in the molten layer, reduce the surface roughness and improve the engraving quality. Experiments have proved that the surface roughness (Ra) can be reduced by more than 90% compared with linearly polarized Gaussian beam.

[0085] In the description of the application, reference has been made to descriptive terms such as "one embodiment", "some embodiments", "an embodiment", "example", "specific example" or "some examples" etc. Such terminology means that a particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the application. The illustrative appearances of such terminology in various places in the specification does not necessarily refer to the same embodiment or example. Moreover, it is appreciated that the specific features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0086] Although embodiments of the present application have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations to these embodiments could be made without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A method of engraving processing based on a vector pulse laser, characterized by, The method comprises the following steps: splitting a linearly polarized femtosecond pulse laser into a first femtosecond pulse laser and a second femtosecond pulse laser; determining the first femtosecond pulse laser as a femtosecond prepulse laser and expanding the second femtosecond pulse laser into a picosecond main pulse laser; adjusting the pulse time delay between the femtosecond prepulse laser and the picosecond main pulse laser; combining the femtosecond prepulse laser and the picosecond main pulse laser after the time delay adjustment; converting the femtosecond prepulse laser into an angularly polarized femtosecond prepulse beam and the picosecond main pulse laser into a radially polarized picosecond main pulse beam to form a dual-pulse beam combination of the angularly polarized femtosecond prepulse beam and the radially polarized picosecond main pulse beam; ablation engraving a workpiece to be processed by using the dual-pulse beam combination.

2. The vector-pulse laser-based engraving method according to claim 1, characterized in that, The ablation engraving step of the workpiece to be processed by using the dual-pulse beam combination comprises: the angularly polarized femtosecond prepulse beam pre-processes the workpiece to be processed to form a processing improvement layer; the radially polarized picosecond main pulse beam performs a secondary etching process on the processing improvement layer; wherein the pulse time delay of the pre-processing and the secondary etching process is set to 1 ps to 100 ps, and the pulse time delay is the time difference between the angularly polarized femtosecond prepulse beam and the radially polarized picosecond main pulse beam reaching the workpiece to be processed.

3. The vector-pulse laser based engraving method according to claim 2, wherein The step of the angularly polarized femtosecond prepulse beam pre-processing the workpiece to be processed to form a processing improvement layer comprises: the angularly polarized femtosecond prepulse beam forms a ring-shaped electric field on the surface of the workpiece to be processed; the ring-shaped electric field excites the electronic active state of the material surface layer and excites the material surface layer into plasma; the angularly polarized femtosecond prepulse beam heats the plasma to the melting point of the material to form the processing improvement layer.

4. The vector-pulse laser based engraving method according to claim 1, wherein The step of converting the femtosecond prepulse laser into an angularly polarized femtosecond prepulse beam and the picosecond main pulse laser into a radially polarized picosecond main pulse beam to form a dual-pulse beam combination of the angularly polarized femtosecond prepulse beam and the radially polarized picosecond main pulse beam comprises: by adjusting the reference axis of a vortex wave plate, the polarization direction of the femtosecond prepulse laser is perpendicular to the reference axis, and the polarization direction of the picosecond main pulse laser is parallel to the reference axis; the femtosecond prepulse laser passing through the vortex wave plate is converted into the angularly polarized femtosecond prepulse beam, and the picosecond main pulse laser passing through the vortex wave plate is converted into the radially polarized picosecond main pulse beam to form the dual-pulse beam combination; wherein the angularly polarized femtosecond prepulse beam can excite a radial radial surface structure along the material surface, and the radially polarized picosecond main pulse beam can excite a concentric circular surface structure around the material center.

5. The vector-pulse laser based engraving method according to claim 1, wherein The step of adjusting the pulse time delay between the femtosecond prepulse laser and the picosecond main pulse laser comprises: after the femtosecond prepulse laser irradiates the workpiece to be processed, collecting the plasma spectrum of the workpiece to be processed at the first time point; Intensity values of two preset wavelengths are extracted from the plasma spectrum, and a characteristic intensity ratio is calculated; When the characteristic intensity falls within a delay threshold range, the picosecond main pulse laser is triggered, and the trigger time difference between the femtosecond pre-pulse laser and the picosecond main pulse laser is determined as the pulse time delay; when the characteristic intensity does not fall within the delay threshold range, the first time is re-determined until the pulse time delay is determined.

6. The vector-pulse laser based engraving method according to claim 5, wherein The step of extracting intensity values of two preset wavelengths from the plasma spectrum and calculating a characteristic intensity ratio comprises: Obtaining the material of the workpiece to be processed, and determining the preset wavelength according to the material of the workpiece to be processed; According to the plasma spectrum, the first intensity value and the second intensity value corresponding to the preset wavelength are determined; The characteristic intensity ratio is determined according to the ratio of the second intensity value to the first intensity value; The first intensity value is less than the second intensity value.

7. A vector-pulse laser-based engraving system, characterized by comprising: A vector pulse laser-based engraving processing method is provided.

8. The vector-pulse laser based engraving system according to claim 7, wherein It comprises: A femtosecond laser source module for emitting linearly polarized femtosecond pulse laser; A workbench for placing a workpiece to be processed; A beam splitting module arranged between the femtosecond laser source module and the workbench for splitting the linearly polarized femtosecond pulse laser into a first femtosecond pulse laser and a second femtosecond pulse laser, and using the first femtosecond pulse laser as a femtosecond pre-pulse laser; A pulse width expansion module arranged between the beam splitting module and the workbench for expanding the second femtosecond pulse laser into a picosecond main pulse laser; A delay control module arranged between the beam splitting module and the workbench for adjusting the pulse time delay between the femtosecond pre-pulse laser and the picosecond main pulse laser; A beam combining module arranged between the delay control module and the workbench for combining the delay-controlled femtosecond pre-pulse laser and the picosecond main pulse laser; A vector conversion module arranged between the beam combining module and the workbench for converting the femtosecond pre-pulse laser into an angularly polarized femtosecond pre-pulse beam and the picosecond main pulse laser into a radially polarized picosecond main pulse beam, forming a dual-pulse beam combination of the angularly polarized femtosecond pre-pulse beam and the radially polarized picosecond main pulse beam.

9. The vector-pulse laser based engraving system according to claim 8, characterized in that It also includes: A beam expansion module arranged between the beam combining module and the vector conversion module for expanding the beam diameter of the dual-pulse beam combination; A motion control module arranged between the vector conversion module and the workbench for moving the dual-pulse beam combination to ablate and engrave the workpiece to be processed, the motion control module comprising two scanning galvanometers, the reflection direction of the dual-pulse beam being changed by adjusting the angles of the two scanning galvanometers.

10. The vector-pulse laser based engraving system of claim 9, wherein, The delay control module comprises: A first adjustment table arranged between the beam splitting module and the beam combining module for changing the optical path of the first femtosecond pulse laser; A second adjusting station is arranged between the beam splitting module and the beam combining module, and is used for changing the optical path of the second femtosecond pulse laser.

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