Bessel beam-based double-helix structure micropore processing method and system

Abstract

The invention provides a double-spiral-structure micropore machining method and system based on a Bessel beam. The processing method comprises the following steps: performing high-frequency component elimination and beam-expanding collimation on a laser beam through a filtering and beam-expanding collimation module; light beams are adjusted through a light power and polarization direction adjusting module to generate polarized light; performing phase modulation on the light beam through a phase modulation module to enable the wavefront of the light beam to be of a spiral structure; the light beam is divided into two beams through a wavefront chiral mirror image module, the two beams are respectively reflected for a plurality of times, and one beam is added into a timeline to adjust time delay; the two paths of light beams are modulated through a Bessel light beam generation module to generate Bessel light beams, and then the Bessel light beams are combined; and the beam-combined light is focused through the light beam focusing module. By means of the machining method, the machining precision of the spiral structure micropores is improved.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a method and system for processing microholes with a double helix structure based on Bessel beams. Background Technology

[0002] In recent years, with the development of industrial technology, the demand for processing helical micropore structures in some materials has gradually emerged and is increasing. Specifically, the rapid development of fields such as precision optical devices, biomedical implants, and microfluidic chips has placed higher demands on the processing of three-dimensional micro-nano structures of transparent materials (such as sapphire, fused silica, and polymers).

[0003] Traditional mechanical drilling is difficult to bend; chemical etching is difficult to control the etching direction due to its isotropic nature; and conventional Gaussian laser processing is similar to traditional drilling methods in that it is difficult to bypass obstacles because its light energy is relatively concentrated and moves forward along the central axis, so the micro-holes it produces are often cylindrical. Obviously, these technologies are difficult to achieve with traditional methods in the processing of micro-holes with spiral structures.

[0004] Spiral micropores are not entirely impossible to process. For example, by controlling the movement of the laser focus in the three-dimensional space of a transparent material, especially the movement in the depth direction, three-dimensional engraving of the material's interior can be achieved. However, this method has high requirements for motion control equipment, and because it is a mechanical motion control method, its processing accuracy is low. Summary of the Invention

[0005] The purpose of this invention is to provide a method for fabricating micro-holes with a double helix structure based on Bessel beams, so as to solve the problem of low processing accuracy in existing methods for fabricating micro-holes with helical structures.

[0006] This invention provides a method for fabricating micropores with a double helix structure based on Bessel beams, comprising: A laser beam is generated by a laser; The high-frequency components of the laser beam are eliminated and the beam is expanded and collimated through the filtering and beam expansion collimation module, and the beam is transmitted to the optical power and polarization direction adjustment module. The optical power and polarization direction adjustment module adjusts the light beam to generate polarized light, and then transmits the light beam to the phase modulation module; The phase modulation module modulates the beam to make the wavefront of the beam spiral, and then transmits the beam to the wavefront chiral mirror module. The wavefront chiral mirror module splits the beam into two beams, which are then reflected several times before being transmitted to the Bessel beam generation module. One of the beams is added to the timeline to adjust the time delay. The two beams are modulated by the Bessel beam generation module to generate a Bessel beam, which is then combined and transmitted to the beam focusing module. The beam focusing module focuses the combined beam and transmits it to the stage to process the material.

[0007] Preferably, based on the optical power and polarization direction adjustment module, the light beam is passed through a combination of two Glan prisms to generate linearly polarized light, and the power adjustment range is controlled within 0-100%.

[0008] Preferably, based on the optical power and polarization direction adjustment module, the light beam is passed through a combination of a Glan prism and an attenuator to generate linearly polarized light, and the power adjustment range is controlled within 0-100%.

[0009] Preferably, based on the optical power and polarization direction adjustment module, the light beam is passed through a combination of a Glan prism and a λ / 4 glass plate to generate circularly polarized light, and the power adjustment range is controlled to be 0-100%; at the same time, based on the phase modulation module, the light beam is passed through a combination of a vortex half-wave plate, a λ / 4 glass plate and a Glan prism, so that the wavefront of the light beam has a spiral structure.

[0010] Preferably, based on the beam focusing module, the combined beam is focused sequentially through a long focal length lens and a short focal length lens.

[0011] This invention also provides a micro-hole fabrication system based on Bessel beams for a double-helix structure, adapted to the above-described fabrication method, the system comprising: A laser generating device, configured to generate a laser beam; The filtering and beam expansion and collimation module is configured to eliminate high-frequency components and expand and collimate the laser beam, and transmit the beam to the optical power and polarization direction adjustment module; The optical power and polarization direction adjustment module is configured to adjust the beam to generate polarized light and transmit the beam to the phase modulation module; The phase modulation module is configured to perform phase modulation on the beam, making the wavefront of the beam a spiral structure, and transmit the beam to the wavefront chiral mirror module. The wavefront chiral mirror module is configured to split the beam into two beams, which are then transmitted to the Bessel beam generation module after undergoing several reflections. One of the beams is added to a timeline to adjust the time delay. The Bessel beam generation module is used to modulate two beams to generate a Bessel beam, combine them, and transmit the combined beam to the beam focusing module. The beam focusing module is configured to focus the combined beam and transmit it to the stage to process the material.

[0012] Preferably, the optical power and polarization direction adjustment module consists of two Glan prisms. The light beam passes through the optical power and polarization direction adjustment module to generate linearly polarized light, and the power adjustment range is controlled within 0-100%.

[0013] Preferably, the optical power and polarization direction adjustment module comprises a Glan prism and an attenuator. The light beam passes through the optical power and polarization direction adjustment module to generate linearly polarized light, and the power adjustment range is controlled within 0-100%.

[0014] Preferably, the optical power and polarization direction adjustment module consists of a Glan prism and a λ / 4 glass plate, and the phase modulation module consists of a vortex half-wave plate, a λ / 4 glass plate, and a Glan prism. The light beam passes through the optical power and polarization direction adjustment module to generate linearly polarized light, and controls the power adjustment range to 0-100%; then it passes through the phase modulation module to make the wavefront of the light beam spiral.

[0015] Preferably, the beam focusing module consists of a long focal length lens and a short focal length lens, and the combined beam is focused by passing through the long focal length lens and the short focal length lens in sequence.

[0016] The processing method of the present invention adjusts the laser beam through a filtering and beam expansion and collimation module, an optical power and polarization direction adjustment module, a phase modulation module, a wavefront chiral mirror module, a Bessel beam generation module, and a beam focusing module to generate a beam with Bessel beam and Bessel beam characteristics, so as to process double helix structure micropores on transparent materials that are difficult to process by conventional methods. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the process steps of a method for fabricating micro-holes in a double-helix structure based on a Bessel beam, according to the present invention. Figure 2 This is a schematic diagram of the composition of a double-helix micro-hole fabrication system based on Bessel beams according to the present invention. Figure 3 This is a schematic diagram of the optical path structure of one embodiment of the double-helix micro-hole fabrication system based on Bessel beams according to the present invention. Figure 4 This is a schematic diagram of the optical path structure of another embodiment of the double-helix structure micro-hole fabrication system based on Bessel beams according to the present invention. Figure 5 This is a schematic diagram of the optical path structure of another embodiment of the double-helix micro-hole fabrication system based on Bessel beams according to the present invention.

[0018] Appendix Figure 2In the middle: 100-Laser generator; 200-Filtering and beam expansion / collimation module; 300-Optical power and polarization direction adjustment module; 400-Phase modulation module; 500-Wavefront chiral mirror module; 600-Bessel beam generation module; 700-Beam focusing module; 800-Stage; Appendix Figure 3 In the middle: 1-Laser generator; 2-Short focal length lens; 3-Pinhole filter; 4-Long focal length lens; 5-Reflector; 6-Glan prism; 7-Helical phase plate; 8-Optical beam splitter; 9-Silver mirror; 10-Axis pyramid; 11-Silver mirror; 12-Axis pyramid; 13-Optical beam combiner; 14-Long focal length lens; 15-Short focal length lens; 16-Stage.

[0019] Appendix Figure 4 In the middle: 1-Laser generator; 2-Short focal length lens; 3-Pinhole filter; 4-Long focal length lens; 5-Reflector; 6-Glan prism; 7-Spiral phase plate; 8-Optical beam splitter; 9-Silver mirror; 10-Axis pyramid; 11-Silver mirror; 12-Axis pyramid; 13-Optical beam combiner; 14-Objective lens; 15-Stage.

[0020] Appendix Figure 5 In the middle: 1-Laser generator; 2-Short focal length lens; 3-Pinhole filter; 4-Long focal length lens; 5-Glan prism; 6-Reflector; 7-λ / 4 glass slide; 8-Vortex half-wave plate; 9-Vortex half-wave plate; 10-Glan prism; 11-Optical beam splitter; 12-Reflector; 13-Axis pyramid; 14-Reflector; 15-Axis pyramid; 16-Optical beam combiner; 17-Objective lens; 18-Stage. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "joined" should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal communication of two components. For those skilled in the art, the specific meaning of the terms in this invention can be understood according to the specific circumstances.

[0023] This invention provides a method for fabricating micropores with a double-helix structure based on Bessel beams. Please refer to [link / reference]. Figure 1 The processing methods include: Step 1: A laser beam is generated by a laser.

[0024] Step 2: The high-frequency components of the laser beam are eliminated and the beam is expanded and collimated through the filtering and beam expansion collimation module, and the beam is transmitted to the optical power and polarization direction adjustment module.

[0025] In one embodiment, based on the filtering and beam-expanding collimation module, the beam is sequentially focused, filtered, and expanded and collimated, i.e., step 2 includes: Step 21: Focus the light beam using a short focal length lens; Step 22: Filter the beam using a pinhole filter; Step 23: Expand and collimate the beam using a telephoto lens.

[0026] Step 3: The beam is adjusted to generate polarized light through the optical power and polarization direction adjustment module, and the beam is transmitted to the phase modulation module.

[0027] Specifically, the optical power and polarization direction adjustment module adjusts the polarization direction and intensity of the light beam, thereby producing polarized light and controlling the power adjustment range to 0-100%.

[0028] In one embodiment, the light beam is passed through a combination of two Glan prisms to generate linearly polarized light, based on the optical power and polarization direction adjustment module.

[0029] In one embodiment, based on the optical power and polarization direction adjustment module, the light beam is passed through a combination of a Glan prism and an attenuator to generate linearly polarized light. That is, step 3 includes: Step 31: Pass the beam through a Glan prism; Step 32: Pass the beam through an attenuator.

[0030] In one embodiment, based on the optical power and polarization direction adjustment module, the light beam is passed through a combination of a Glan prism and a λ / 4 glass plate to generate circularly polarized light. That is, step 3 includes: Step 301: Pass the beam through a Glan prism; Step 302: Pass the beam through a λ / 4 glass slide.

[0031] Step 4: The phase modulation module modulates the beam to make the wavefront of the beam spiral, and then transmits the beam to the wavefront chiral mirror module.

[0032] Among them, based on the phase modulation module, the phase of the beam is modulated by a spiral phase plate, a spatial light modulator, or a microlens array, and the phase modulation module is used to modulate the wavefront phase to generate a rotating light field.

[0033] Furthermore, if step 3 uses a combination of passing the beam through a Glan prism and a λ / 4 glass plate to generate circularly polarized light, then this step corresponds to passing the beam through a combination of a vortex half-wave plate, a λ / 4 glass plate, and a Glan prism, making the wavefront of the beam spiral. That is, step 4 includes: Step 41: Pass the beam through a vortex half-wave plate; Step 42: Pass the beam through a λ / 4 glass slide; Step 43: Pass the beam through a Glan prism.

[0034] Step 5: The beam is split into two beams by the wavefront chiral mirror module. The two beams are reflected several times and then transmitted to the Bessel beam generation module. One of the beams is added to the timeline to adjust the time delay.

[0035] In this design, based on a wavefront chiral mirror module, the beam is split by an optical beam splitter and reflected by mirrors. By utilizing reflections of different odd and even orders, coherent superposition of the chiral mirror beams is achieved. Since the axial wave vectors k1z≠k2z of the two beams near the focal point are not equal, a light field is finally modulated, where the intensity distribution rotates around the z-axis as the spatial z-coordinate changes, and the intensity distribution remains stable at the same spatial location. Optionally, one beam undergoes four reflections (using the optical beam splitter and three mirrors), while the other beam undergoes three reflections (using two mirrors and the optical combiner of the Bessel beam generation module). Alternatively, one beam undergoes four reflections (using the optical beam splitter, two mirrors, and the optical combiner of the Bessel beam generation module), while the other beam undergoes one reflection (using one mirror).

[0036] Step 6: After the two beams are modulated to generate a Bessel beam by the Bessel beam generation module, the beams are combined and the combined beam is transmitted to the beam focusing module.

[0037] Specifically, based on the Bessel beam generation module, the two beams pass through an axial pyramid and are then converged in an optical combiner. That is, step 6 includes: Step 61: Pass the two beams through the axial pyramid respectively; Step 62: Combine the two beams using an optical beam combiner.

[0038] A Bessel beam that utilizes an axial pyramid to generate a rotating light field possesses the diffraction-free and self-healing properties of a Bessel beam. Its intensity distribution can propagate stably within a certain propagation distance without being affected by obstacles.

[0039] Step 7: Focus the combined beam using the beam focusing module and transmit the combined beam to the stage to process the material.

[0040] Specifically, based on the beam focusing module, the laser beam is focused to maintain the characteristics of a Bessel beam while concentrating the energy of the two rotating Bessel beams, reaching the energy threshold for material breakdown. After placing the material to be processed behind the beam focusing module, the laser will burn a spiral-shaped hole inside the material, consistent with the light field distribution.

[0041] In one embodiment, the light beam may be focused using an objective lens.

[0042] In another embodiment, the light beam may be focused by sequentially passing it through a lens group consisting of a long focal length lens and a short focal length lens, i.e., step 7 includes: Step 71: Pass the light beam through a telephoto lens; Step 72: Pass the light beam through the long focal length lens, and then through the short focal length lens.

[0043] In this application, the Bessel beam possesses diffraction-free and self-healing properties. Within a certain distance, the intensity distribution of the Bessel beam remains constant along the propagation direction. A spiral beam is a beam that rotates around the z-axis during spatial propagation. By combining the characteristics of these two beams, a spiral beam that maintains its shape even behind obstacles can be generated. By simply fixing the relative position of this beam to the transparent material to be processed, and relying on the rotational and self-healing properties of the light field itself, a spiral micro-hole can be etched, reducing costs while improving processing accuracy and efficiency. The processing method of this invention adjusts the laser beam through a filtering and beam-expanding collimation module, an optical power and polarization direction adjustment module, a phase modulation module, a wavefront chiral mirror module, a Bessel beam generation module, and a beam focusing module to generate a beam with the aforementioned characteristics, thereby processing double-spiral micro-holes on transparent materials that are difficult to process using conventional methods.

[0044] This invention also discloses a micro-hole fabrication system based on Bessel beams for double-helix structures, applicable to the micro-hole fabrication method based on Bessel beams disclosed in this invention. Please refer to [link to relevant documentation]. Figure 2 The processing system includes: Laser generator 100; configured to generate a laser beam.

[0045] A filtering and beam-expanding collimation module 200 is configured to eliminate high-frequency components and expand and collimate the laser beam, and then transmit the beam to an optical power and polarization direction adjustment module 300. The filtering and beam-expanding collimation module 200 includes, in sequence along the beam propagation direction, a focusing element, a filtering element, and a beam-expanding collimation element. Optionally, the focusing element is a short-focal-length lens, the filtering element is a pinhole filter, and the beam-expanding collimation element is a long-focal-length lens.

[0046] An optical power and polarization direction adjustment module 300 is configured to adjust the beam to generate polarized light and transmit the beam to a phase modulation module 400. The optical power and polarization direction adjustment module 300 adjusts the polarization direction and intensity of the beam. Optionally, the optical power and polarization direction adjustment module 300 consists of two Glan prisms, generating linearly polarized light and controlling the power adjustment range to 0-100%; or the optical power and polarization direction adjustment module 300 consists of one Glan prism and one attenuator, generating linearly polarized light and controlling the power adjustment range to 0-100%; or the optical power and polarization direction adjustment module 300 consists of one Glan prism, one reflector, and one λ / 4 glass plate, generating circularly polarized light and controlling the power adjustment range to 0-100%.

[0047] It should be noted that when the optical power and polarization direction adjustment module consists of two Glan prisms, the light beam can pass directly through the two Glan prisms sequentially; or the light beam can first pass through one Glan prism, then be reflected by a mirror, and then pass through the other Glan prism, as shown below. Figure 4 As shown; or the beam of light is first reflected by a mirror and then passes through two Glan prisms, such as Figure 3 As shown.

[0048] When the optical power and polarization direction adjustment module 300 consists of one Glan prism and one attenuator, the light beam can first pass through the Glan prism, then be reflected by the mirror, and then pass through the attenuator.

[0049] When the optical power and polarization direction adjustment module 300 consists of one Glan prism and one λ / 4 glass plate, the light beam first passes through the Glan prism, then is reflected by the mirror, and then passes through the λ / 4 glass plate. Figure 5 As shown.

[0050] A phase modulation module 400 is configured to phase modulate the light beam, making the wavefront of the beam spiral, and then transmit the beam to a wavefront chiral mirror module. The phase modulation module 400 can be a spiral phase plate, a spatial light modulator, or a microlens array, and it modulates the wavefront phase to generate a rotating optical field. Alternatively, if the optical power and polarization direction adjustment module 300 is selected to consist of one Glan prism and one λ / 4 glass plate, then the phase modulation module 400 is correspondingly composed of one vortex half-wave plate, one λ / 4 glass plate, and one Glan prism.

[0051] Wavefront chiral mirror module 500; configured to split the beam into two beams, each beam undergoing several reflections before being transmitted to Bessel beam generation module 600; one beam is added to a timeline to adjust the time delay.

[0052] The wavefront chiral mirror module 500 includes an optical beam splitter and a reflector. Reflection is achieved through the reflector, and coherent superposition of chiral mirror beams is completed using reflections of different odd and even numbers. Since the axial wave vectors k1z≠k2z of the two beams near the focal point are not equal, a light field is finally modulated so that the light intensity distribution rotates around the z-axis as the spatial z-coordinate changes, and the light intensity distribution remains stable at the same spatial location. Optionally, one beam undergoes four reflections (four times) through the optical beam splitter and three reflectors, while the other beam undergoes three reflections (three times) through two reflectors and the optical combiner of the Bessel beam generation module 600. Alternatively, one beam undergoes four reflections (four times) through the optical beam splitter, two reflectors, and the optical combiner of the Bessel beam generation module 600, while the other beam undergoes one reflection (one time) through one reflector.

[0053] A Bessel beam generation module 600 is used to modulate two beams to generate a Bessel beam, combine them, and transmit the combined beam to a beam focusing module 700. The Bessel beam generation module 600 consists of an axial pyramid and an optical combiner. The two beams pass through the axial pyramid and are then combined in the optical combiner. By using the axial pyramid to generate a rotating light field, the Bessel beam possesses the diffraction-free and self-healing properties of a Bessel beam, and its intensity distribution can propagate stably within a certain propagation distance without being affected by obstacles.

[0054] A beam focusing module 700 is configured to focus the combined beam and transmit it to a stage 800 for processing the material. The beam focusing module 700 can be an objective lens or a lens composed of a long-focal-length lens and a short-focal-length lens. By focusing the beam using the beam focusing module 700, the laser maintains the characteristics of a Bessel beam while concentrating the energy of the two Bessel rotating beams to reach the energy threshold required to break down the material. The material to be processed is placed after the beam focusing module, and the laser will burn a spiral-shaped hole inside the material that matches the light field distribution. The stage 800 has three-dimensional adjustment capabilities, namely displacement in the x, y, and z directions, or five-dimensional adjustment capabilities, including x, y, and z axis translation and x, y axis angle adjustment. The material to be processed is transparent and can be quartz glass, acrylic, or polystyrene.

[0055] Example 1 Please see Figure 3 , Figure 3 This is a schematic diagram of the optical path structure of a processing system according to an embodiment of the present invention. Figure 3 As shown, the filtering and beam-expanding collimation module 200 of this processing system consists of a short-focal-length lens 1, a pinhole filter 2, and a long-focal-length lens 3. The optical power and polarization direction adjustment module 300 consists of two Glan prisms 6. The phase modulation module 400 consists of a spiral phase plate 7. The wavefront chiral mirror module 500 consists of a beam splitter 8 and mirrors (9, 11). The Bessel beam generation module 600 consists of an axial pyramid (10, 12) and a beam combiner 13. The beam focusing module 700 consists of a long-focal-length lens 14 and a short-focal-length lens 15.

[0056] In this embodiment, laser 1 is a 532nm pulsed laser with a repetition frequency of 10Hz, a power of 500mW, and a spot radius of approximately 4mm.

[0057] In this embodiment, the short focal length lens 2 is focused using a plano-convex lens with f=150mm. A pinhole filter 3 with a circular aperture of 0.01mm is placed near the beam waist. A long focal length lens 4 with f=200mm is placed approximately 200mm behind the filter. After position adjustment, the rear beam is collimated, and the expanded beam radius is approximately 5.3mm. The collimated beam is reflected by the reflector 5 to the two Glan prisms 6.

[0058] In this embodiment, the Glan prism 6 is made of ultraviolet-grade calcium fluoride material, with an anti-reflection coating of 532nm wavelength on its surface. Its light-transmitting aperture is 15mm, the extinction ratio is 100000:1, the polarization adjustment accuracy is better than 0.5°, and the light intensity attenuation range is 0-100%, which is continuously adjustable.

[0059] In this embodiment, the spiral phase plate 7 is a continuous spiral relief structure, made of JGS1 ultraviolet fused quartz, with a component size of 10*10mm and installed in a 25.4mm aperture mechanical housing. Its light transmission aperture is 9*9mm, the working wavelength is 532nm, and the topological charge l=1.

[0060] In this embodiment, the optical beam splitter 8 is a beam splitter with a splitting ratio of 50:50 and an operating wavelength of 532nm.

[0061] In this embodiment, the reflectors (9, 11) are silver mirrors. One beam is reflected four times by the beam splitter 8 and three silver mirrors 9, while the other beam is reflected three times by two silver mirrors 11 and the beam combiner 13.

[0062] In this embodiment, the two axial pyramids are axial pyramid 10 and axial pyramid 12, both made of fused silica, and both have a light-transmitting aperture of 25.4 mm. The base angle of axial pyramid 10 is 8°, and the base angle of axial pyramid 12 is 4.5°.

[0063] In this embodiment, the optical beam 13 uses a beam splitter with a 50:50 splitting ratio and a working wavelength of 532nm.

[0064] In this embodiment, the aperture of the lenses is 50mm, the focal length of the telephoto lens 14 is f1=200mm, the focal length of the short focal length lens 15 is f2=60mm, and the distance between the two lenses is 260mm.

[0065] In this embodiment, the stage 16 has a manual five-dimensional adjustment function, namely xyz displacement and xy axis angle.

[0066] In this embodiment, the processing material is located approximately 60 mm behind the beam focusing module. For a detailed description of the optical path in this embodiment, please refer to [link / reference]. Figure 2After emission, the laser beam is expanded and collimated sequentially through a short-focal-length lens 2, a pinhole filter 2, and a long-focal-length lens 4. Then, after passing through a reflector 5, it passes through two Glan prisms for power and polarization adjustment (or first through one Glan prism 6, then reflected by the reflector 5, and then through another Glan prism 6 for power and polarization adjustment, as shown). Figure 4 (As shown); then the beam is modulated by the spiral phase plate 7; then it is split by the beam splitter 8, one beam is reflected 4 times by the beam splitter 8 and 3 silver mirrors 9, and the other beam is reflected 3 times by the two silver mirrors 11 and the beam combiner 13; the two beams are combined by the beam combiner 13 after passing through the axial pyramid (10, 12); then the beams are focused by the long focal length lens 14 and the short focal length lens 15 in sequence, and finally transmitted to the stage 16 to process the material.

[0067] Example 2 Please see Figure 5 , Figure 5 This is a schematic diagram of the optical path structure of a processing system according to another embodiment of the present invention. Figure 5 As shown, the filtering and beam-expanding collimation module 200 of this processing system consists of a short focal length lens 2, a pinhole filter 3, and a long focal length lens 4. The optical power and polarization direction adjustment module 300 consists of a Glan prism 5, a reflector 6, and a λ / 4 glass plate 7; the phase modulation module 400 consists of a vortex half-wave plate 8, a λ / 4 glass plate 9, and a Glan prism 10. The wavefront chiral mirror module 500 consists of a beam splitter 11 and reflectors (12, 14). The Bessel beam generation module 600 consists of an axial pyramid (13, 15) and a beam combiner 16. The beam focusing module 700 consists of an objective lens 17.

[0068] In this embodiment, laser 1 is a 632nm continuous laser with a power of 10W and a spot radius of approximately 3mm.

[0069] In this embodiment, the short focal length lens 2 is focused using a plano-convex lens with f=100mm. A pinhole filter is placed near the waist of the beam. The diameter of the pinhole filter 3 is 0.01mm. The long focal length lens 4 is placed about 200mm behind the filter. The long focal length lens 4 is a plano-convex lens with f=200mm. After position adjustment, the rear beam is collimated, and the radius of the expanded beam is about 6mm.

[0070] In this embodiment, the Glan prism 5 is made of ultraviolet-grade calcium fluoride material, with an anti-reflection coating of 632nm wavelength on its surface. Its light transmission aperture is 15mm, the extinction ratio is 100000:1, and the light intensity attenuation range is continuously adjustable from 0-100%.

[0071] In this embodiment, the vortex half-wave plate 8 has a light-transmitting aperture of 21.5 mm, an order of m=1, and an operating wavelength of 633 nm.

[0072] In this embodiment, the optical beam splitter 11 is a beam splitter with a splitting ratio of 50:50 and an operating wavelength of 5-632nm.

[0073] In this embodiment, the reflectors (12, 14) are 632nm metal film reflectors. One beam is reflected a total of 4 times by the beam splitter 11 and 3 reflectors 12, and the other beam is reflected a total of 3 times by the 2 reflectors 14 and the beam combiner 16.

[0074] In this embodiment, the two axial pyramids are the first axial pyramid 13 and the second axial pyramid 15, both made of fused silica, and both have a light-transmitting aperture of 25.4 mm. The base angle of the first axial pyramid 13 is 8°, and the base angle of the second axial pyramid 15 is 4.5°.

[0075] In this embodiment, the optical beam combiner 16 is a beam splitter with a 50:50 splitting ratio and an operating wavelength of 632nm.

[0076] In this embodiment, the objective lens 17 has a numerical aperture NA=0.4, a magnification of 10, and a working distance of 20mm.

[0077] In this embodiment, the stage 18 has a manual three-dimensional adjustment function, namely displacement in the xyz direction.

[0078] In this embodiment, the processing material is located approximately 20 mm behind the objective lens described in S7.

[0079] For a detailed description of the optical path in this embodiment, please refer to [link / reference]. Figure 5 After laser emission, the beam is expanded and collimated sequentially through a short focal length lens 2, a pinhole filter 3, and a long focal length lens 4; then through a Glan prism 5, and then through a reflector 6 and a λ / 4 glass plate 7 for power and polarization direction adjustment; then through a vortex half-wave plate 8, a vortex half-wave plate 9, and a Glan prism 10 for phase modulation; then through a beam splitter 11 for beam splitting, one beam is reflected 4 times by the beam splitter 11 and 3 reflectors 12, and the other beam is reflected 3 times by 2 reflectors 14 and a beam combiner 16; the two beams are combined by the beam combiner 16 after passing through an axial pyramid (13, 15); then through an objective lens 17 for beam focusing, and finally transmitted to the stage 18 for processing the material.

[0080] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for processing a micro-hole in a double helix structure based on a Bessel beam, characterized in that, The application relates to a laser beam processing system. A laser beam is generated by a laser; The laser beam is subjected to high-frequency component elimination and beam expansion collimation by a filtering and beam expansion collimation module, and is transmitted to a light power and polarization direction adjusting module; The light beam is adjusted by the light power and polarization direction adjusting module to generate polarized light, and the light beam is transmitted to a phase modulation module; The phase modulation module modulates the light beam to make the wavefront of the light beam a spiral structure, and the light beam is transmitted to a wavefront chiral mirror module; The wavefront chiral mirror module divides the light beam into two beams, and the two beams are transmitted to a Bessel beam generating module after being reflected for several times; one of the two beams is added with a time line to adjust the time delay; The Bessel beam generating module modulates the two beams to generate Bessel beams, and the Bessel beams are combined, and the combined light is transmitted to a light beam focusing module; The light beam focusing module focuses the combined light, and the combined light is transmitted to a worktable to process a material to be processed.

2. The method of claim 1, wherein the method is a Bessel beam based double helix microvia machining method. Based on the light power and polarization direction adjusting module, the light beam passes through a combination of two Glan prisms to generate linearly polarized light, and the power adjustment range is controlled to be 0-100%.

3. The method of claim 1, wherein the method is a Bessel beam based double helix microvia machining method. Based on the light power and polarization direction adjusting module, the light beam passes through a combination of one Glan prism and one lambda / 4 plate to generate circularly polarized light, and the power adjustment range is controlled to be 0-100%; meanwhile, based on the phase modulation module, the light beam passes through a combination of one vortex half-wave plate, one lambda / 4 plate and one Glan prism, so that the wavefront of the light beam is a spiral structure.

4. The method of claim 1, wherein the method is a Bessel beam based double helix microvia machining method. Based on the Bessel beam generating module, the two beams pass through an axicon respectively and are aggregated in a light combiner.

5. The method of claim 1, wherein the method is a Bessel beam based double helix microvia machining method. Based on the light beam focusing module, the combined light passes through a long-focus lens and a short-focus lens in sequence for focusing.

6. A bessel-beam-based double-helical microvia machining system, comprising: The application relates to a laser beam processing system. A laser beam is generated by a laser; The laser beam is subjected to high-frequency component elimination and beam expansion collimation by a filtering and beam expansion collimation module, and is transmitted to a light power and polarization direction adjusting module; The light beam is adjusted by the light power and polarization direction adjusting module to generate polarized light, and the light beam is transmitted to a phase modulation module; The phase modulation module modulates the light beam to make the wavefront of the light beam a spiral structure, and the light beam is transmitted to a wavefront chiral mirror module; The wavefront chiral mirror module divides the light beam into two beams, and the two beams are transmitted to a Bessel beam generating module after being reflected for several times; one of the two beams is added with a time line to adjust the time delay; The Bessel beam generating module modulates the two beams to generate Bessel beams, and the Bessel beams are combined, and the combined light is transmitted to a light beam focusing module; The light beam focusing module focuses the combined light, and the combined light is transmitted to a worktable to process a material to be processed.

7. The Bessel beam based double-helix microvia machining system of claim 6, wherein, The light power and polarization direction adjusting module is composed of two Glan prisms.

8. The Bessel beam based double-helix microvia machining system of claim 6, wherein, The light power and polarization direction adjusting module is composed of one Glan prism and one lambda / 4 plate, and the phase modulation module is composed of one vortex half-wave plate, one lambda / 4 plate and one Glan prism.

9. The Bessel beam based double-helix microvia machining system of claim 6, wherein, The Bessel beam generating module is composed of an axicon and a light combiner.

10. The Bessel beam based double-helix microvia machining system of claim 6, wherein, The light beam focusing module is composed of a long-focus lens and a short-focus lens, and the combined light sequentially passes through the long-focus lens and the short-focus lens for focusing.

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