Ultrahigh vacuum machining system based on femtosecond laser space-time frequency shaping

Abstract

The invention provides an ultrahigh vacuum machining system based on femtosecond laser space-time frequency shaping, relates to the technical field of femtosecond laser shaping, and provides the ultrahigh vacuum machining system based on femtosecond laser space-time frequency shaping which is sequentially provided with a pre-shaping unit, a space-domain shaping unit, a time-domain shaping unit and an in-situ observation unit. The pre-shaping unit is used for weakening the intensity of a light beam and limiting the diameter and the position of the light beam to form a calibration light beam; the airspace shaping unit adjusts the phase and amplitude of the light beam through a spatial light modulator to form an airspace shaped light beam; the time domain shaping unit performs beam splitting through a time domain beam splitter and adjusts an optical path by using a time domain reflector to realize pulse delay and form a time domain shaping light beam, and finally, in the in-situ observation unit, high-precision light beam convergence and sample processing are realized. According to the scheme, the beam quality and the machining precision of the femtosecond laser can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of femtosecond laser shaping, and particularly to an ultra-high vacuum processing system based on spatio-temporal-frequency shaping of femtosecond laser. Background Art

[0002] With the rapid development of modern science and technology, femtosecond lasers have been widely used in the fields of material processing, micro-nano manufacturing, and biomedicine. Femtosecond lasers have an extremely short pulse width and high instantaneous power, enabling precise processing and high-resolution imaging. However, in practical applications, the beam quality and pulse characteristics of femtosecond lasers play a crucial role in the processing and observation effects. Therefore, how to precisely perform spatio-temporal-frequency shaping on femtosecond lasers has become a key technical issue for improving their application effects.

[0003] Femtosecond laser processing technology occupies an important position in the fields of precision manufacturing and material processing due to its advantages of non-contact, pollution-free, high efficiency, and "cold processing". The ultrashort pulses generated by femtosecond lasers can deliver a large amount of energy to the material surface in an extremely short time, thereby achieving high-precision local material removal and forming a very small heat-affected zone. In addition, based on femtosecond lasers, the application of spatio-temporal-frequency shaping technology further expands the capabilities of femtosecond laser processing. By finely shaping the spatio-temporal characteristics of femtosecond laser pulses, such as adjusting the pulse duration, shape, and energy distribution, femtosecond laser processing can achieve more complex material processing tasks, including precise energy deposition, specific processing path design, and customized modification of material surface and internal structures.

[0004] Existing femtosecond laser shaping methods are usually divided into time-domain shaping and spatial-domain shaping. However, in practical applications, single time-domain or spatial-domain shaping often fails to meet the requirements of high-precision processing and observation. For example, time-domain shaping can solve the problems of pulse broadening and dispersion, but it cannot effectively control the spatial distribution of the beam; while spatial-domain shaping can adjust the spatial distribution of the beam, but its improvement of pulse characteristics is limited. In addition, there is a lack of an effective way to organically combine time-domain shaping and spatial-domain shaping in the existing technology, resulting in poor beam shaping effects and affecting processing accuracy and observation effects.

[0005] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present disclosure, and therefore it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide an ultra-high vacuum processing system based on spatio-temporal-frequency shaping of femtosecond laser to solve the problems raised in the above background art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] An ultra-high vacuum processing system based on femtosecond laser spatio-temporal frequency shaping, comprising a femtosecond laser, wherein:

[0009] On the optical path of the femtosecond laser output, a pre-shaping unit, a spatial domain shaping unit, a time domain shaping unit, and an in-situ observation unit are sequentially arranged;

[0010] The pre-shaping unit is used to weaken the intensity of the light beam to control the energy level, and to limit the diameter and position of the light beam to ensure that the light beam is calibrated along the center to form a calibrated light beam;

[0011] The spatial domain shaping unit includes a spatial light modulator, and the spatial light modulator is used to modulate and shape the calibrated light beam by adjusting the phase and amplitude of the internal pixels of the spatial light modulator to form a spatially shaped light beam;

[0012] The time domain shaping unit includes a time domain beam splitter and a time domain mirror mounted on a guide rail. The spatially shaped light beam is split into two beams by the time domain beam splitter. One of the beams continues to propagate in the original direction, is reflected by the time domain mirror, and is reflected by the beam splitter to form a time domain shaped light beam. The time domain mirror adjusts the optical path by moving on the guide rail to form an optical path difference to achieve pulse delay;

[0013] The in-situ observation unit includes a dichroic mirror and an observation beam splitter. After the illumination beam generated by the illumination device passes through the observation beam splitter and the dichroic mirror, the beam reflected by the dichroic mirror together with the time domain shaped light beam is input to the vacuum processing unit;

[0014] The vacuum processing unit includes an objective lens and a three-dimensional precision displacement stage. The beam output by the in-situ observation unit is converged at the same focus by the objective lens to process the sample on the three-dimensional precision displacement stage.

[0015] Furthermore, the pre-shaping unit includes a beam splitter, an attenuation sheet, and two pre-shaping apertures. The femtosecond laser is split into multiple beams by the beam splitter. One of the beams passes through the center of the attenuation sheet and the two pre-shaping apertures. The centers of the attenuation sheet and the two pre-shaping apertures are at the same height, and the attenuation sheet is located between the two pre-shaping apertures. The attenuation sheet is used to weaken the intensity of the light beam to control the energy level. The pre-shaping aperture is used to limit the diameter and position of the light beam to ensure that the light beam is calibrated along the center of the pre-shaping aperture to form a calibrated light beam. The pre-shaping unit further includes a first mirror, and the first mirror is used to reflect one of the beams split by the beam splitter to the center of the pre-shaping aperture.

[0016] Further, the spatial domain shaping unit further includes a second mirror and a third mirror. The second mirror is configured to reflect a calibration beam to a spatial light modulator. The spatially shaped beam after modulation and shaping by the spatial light modulator is reflected by the third mirror to a fourth mirror, and the fourth mirror reflects the spatially shaped beam to the time domain shaping unit.

[0017] Further, the spatially shaped beam is split into two beams by a time domain beam splitter. One beam continues to propagate in the original direction, and the other beam is reflected by a fifth mirror to a birefringent crystal.

[0018] Further, the time domain shaped beam is incident on the in-situ observation unit through a calibration unit. The calibration unit includes two calibration diaphragms with centers at the same height. The time domain shaped beam passes through the two calibration diaphragms and then is incident on a dichroic mirror. The two calibration diaphragms are used to limit the diameter and position of the time domain shaped beam to ensure that the beam is calibrated along the center of the calibration diaphragm.

[0019] Further, the calibration unit further includes a sixth mirror and a seventh mirror. The time domain shaped beam is reflected by the sixth mirror to the seventh mirror, and the seventh mirror reflects the time domain shaped beam to the center of the calibration diaphragm.

[0020] Further, the optical axis of the objective lens is coaxial with the beam after the illumination beam passes through the observation beam splitter and the dichroic mirror, and the time domain shaped beam reflected by the dichroic mirror. The in-situ observation unit further includes a charge coupled device. The beam reflected by the sample on the three-dimensional precision displacement stage passes through the dichroic mirror and is then reflected by the observation beam splitter to the charge coupled device, and the charge coupled device converts the received optical signal into an electrical signal.

[0021] Further, the vacuum processing unit further includes an objective lens adjustment manipulator. The objective lens adjustment manipulator is connected to the objective lens through a rotary introducer, enabling the objective lens to perform three-axis movement. The vacuum processing unit is fixed in a vacuum processing chamber. The vacuum processing chamber includes a cylindrical cavity with an internal vacuum. The cavity has a quartz window made of fused quartz. The beam output by the in-situ observation unit enters the interior of the cavity through the quartz window. An optical platform is provided at the bottom of the cavity. A three-dimensional precision displacement stage is mounted on the optical platform. The objective lens is located at the upper end of the three-dimensional precision displacement stage. The objective lens adjustment manipulator is fixed on the cavity and passes through the cavity to be connected to the objective lens through a rotary introducer.

[0022] Furthermore, three layers of flange ports for connection are provided on the cavity. An observation window is provided on the upper flange port. The in-situ AFM characterization window and the quick-opening window are hermetically connected to the middle flange port. The in-situ AFM characterization window is used to observe the processing quality inside the cavity in-situ. The bottom flange port is hermetically connected to an electrode, a vacuum gauge, a micro-leak valve, and a molecular pump. The electrode is electrically connected to the optical platform and the three-dimensional precision displacement stage, and is used to supply power to the optical platform and the three-dimensional precision displacement stage. The vacuum gauge is used to measure the internal pressure of the cavity. The micro-leak valve is used to relieve the pressure of the cavity. A gate valve is also provided on the cavity and is used to interconnect with other vacuum chambers.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The present invention provides an ultra-high vacuum processing system based on femtosecond laser spatio-temporal-frequency shaping. By sequentially arranging a pre-shaping unit, a spatial-domain shaping unit, a time-domain shaping unit, and an in-situ observation unit, precise shaping of the femtosecond laser is achieved. The pre-shaping unit weakens the beam intensity and limits the beam diameter and position to form a calibrated beam. The spatial-domain shaping unit adjusts the phase and amplitude of the beam through a spatial light modulator to form a spatially shaped beam. The time-domain shaping unit splits the beam through a time-domain beam splitter and adjusts the optical path using a time-domain mirror to achieve pulse delay, forming a time-domain shaped beam. Finally, in the in-situ observation unit, high-precision beam focusing and sample processing are achieved. Through this systematic spatio-temporal-frequency shaping method, the present solution can effectively improve the beam quality and processing accuracy of the femtosecond laser. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of the overall system structure of the processing system of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of the vacuum processing chamber of the present invention.

[0027] Reference Numerals: Pre-shaping Unit 10, Spatial-domain Shaping Unit 20, Time-domain Shaping Unit 30, In-situ Observation Unit 50, Vacuum Processing Unit 60, Objective Lens 61, Three-dimensional Precision Displacement Stage 62, Objective Lens Adjusting Manipulator 63, Vacuum Processing Chamber 70, Cavity 71, Optical Platform 72, Observation Window 73, In-situ AFM Characterization Window 74, Quick-opening Window 75, Electrode 76, Vacuum Gauge 77, Micro-leak Valve 78, Molecular Pump 79. Detailed Embodiments

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments.

[0029] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those with ordinary skills in the field to which the present invention pertains. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0030] Embodiment:

[0031] Please refer to Figure 1 - Figure 2 , the present invention provides a technical solution:

[0032] An ultra-high vacuum processing system based on femtosecond laser spatio-temporal frequency shaping, comprising a femtosecond laser, wherein:

[0033] The femtosecond laser is used to generate femtosecond laser. On the optical path of the femtosecond laser output, a pre-shaping unit 10, a spatial domain shaping unit 20, a time domain shaping unit 30 and an in-situ observation unit 50 are sequentially arranged, wherein:

[0034] The pre-shaping unit 10 is used to weaken the intensity of the light beam to control the energy level, and to define the diameter and position of the light beam to ensure that the light beam is calibrated along the center to form a calibrated light beam.

[0035] In this embodiment, the pre-shaping unit 10 includes a beam splitter A01, an attenuation sheet A04 and two pre-shaping diaphragms A03, A05. The femtosecond laser is split into multiple light beams by the beam splitter A01. One of the light beams passes through the center of the attenuation sheet A04 and the two pre-shaping diaphragms A03, A05. The centers of the attenuation sheet A04 and the two pre-shaping diaphragms A03, A05 are at the same height, and the attenuation sheet A04 is located between the two pre-shaping diaphragms A03, A05. The attenuation sheet A04 is used to weaken the intensity of the light beam to control the energy level, and the pre-shaping diaphragms A03, A05 are used to define the diameter and position of the light beam to ensure that the light beam is calibrated along the center of the pre-shaping diaphragm to form a calibrated light beam.

[0036] In a femtosecond laser spatio-temporal frequency shaping system, the design and implementation of the pre-shaping unit 10 are crucial for the performance of the entire system. The beam splitter A01 divides the femtosecond laser beam into multiple beams. The beam output from the femtosecond laser passes through the beam splitter A01, and part of the beam is reflected or transmitted, forming multiple beams. This can be used for parallel processing or guiding into different optical paths. The attenuator A04 can weaken the intensity of the beam and control the energy level. One of the split beams passes through the attenuator A04. The attenuator is selected according to the material and thickness and can absorb or scatter part of the light energy, thereby reducing the intensity of the beam. The purpose of this step is to ensure that the light intensity of the subsequent processing unit is within a safe and effective range.

[0037] The pre-shaping diaphragms A03 and A05 can limit the diameter and position of the beam, ensuring that the beam is calibrated along the center. The apertures of the pre-shaping diaphragms A03 and A05 are set to the required beam diameter. The pre-shaping diaphragms A03 and A05 only allow beams with a specific diameter to pass through, and the other parts are blocked. The centers of the two pre-shaping diaphragms A03 and A05 are at the same height, and the attenuator A04 is located between them. This arrangement ensures that the beams passing through and from the attenuator A04 can accurately pass through the centers of the two diaphragms, thereby calibrating the position of the beam and ensuring its propagation along the center line. By setting the two diaphragms, it can be ensured that the propagation path of the beam in space is a straight line, that is, the divergence or deviation of the beam is corrected, forming a centrally calibrated beam.

[0038] The intensity of the beam is weakened and controlled by the attenuator A04 to ensure that the light intensity required for the subsequent optical unit and processing process is within an appropriate range, avoiding damage to optical components or poor processing effects caused by excessive light intensity. The diameter of the beam is limited by the apertures of the pre-shaping diaphragms A03 and A05, forming a consistent beam diameter, ensuring a uniform spatial distribution of the beam in subsequent processing, which helps to improve the accuracy of shaping and processing. The centers of the two pre-shaping diaphragms A03 and A05 are at the same height, enabling the beam to maintain a straight propagation when passing through the diaphragms. This configuration helps to avoid the deviation of the beam, thereby ensuring that the beam is transmitted along the center line and improving the spatial consistency. Secondly, the attenuator A04 is located between the two diaphragms, which can not only effectively control the intensity of the beam but also weaken the beam after passing through the first diaphragm. This design ensures that the beam has been properly adjusted before entering the second diaphragm, thereby further optimizing the beam diameter and energy distribution and providing a good foundation for subsequent optical processing.

[0039] Furthermore, the pre-shaping unit 10 further includes a first mirror A02, which is configured to reflect one of the light beams split by the beam splitter A01 to the center of the pre-shaping aperture A03. The main function of the first mirror A02 is to reflect one of the light beams split by the beam splitter A01 to the center of the pre-shaping aperture A03. By adjusting the first mirror A02, the propagation path of the light beam can be flexibly changed to ensure that the light beam can accurately enter the center position of the pre-shaping aperture. This helps to achieve a complex optical path layout within a limited space and ensure the accurate calibration of the light beam.

[0040] The laser beam generated by the femtosecond laser first passes through the beam splitter A01. The function of the beam splitter A01 is to split the original laser beam into multiple light beams. One of the light beams is guided to the pre-shaping unit 10 for further processing. The separated light beam is then reflected by the first mirror A02 to the center of the pre-shaping aperture A03. The function of the first mirror A02 is to change the propagation direction of the light beam so that it accurately enters the center of the pre-shaping aperture A03, thereby achieving the precise calibration of the light beam. After the light beam enters the pre-shaping aperture A03, its diameter and position are limited. The function of the pre-shaping aperture A03 is to limit the diameter of the light beam through its aperture and ensure that the light beam propagates along the center line, thereby improving the spatial uniformity of the light beam.

[0041] After passing through the pre-shaping aperture A03, the light beam then passes through the attenuation sheet A04. The main function of the attenuation sheet A04 is to weaken the intensity of the light beam, thereby controlling the energy level of the light beam. This can prevent the light beam from being too strong during subsequent processing and ensure that its energy is moderate. Next, the light beam weakened by the attenuation sheet A04 continues to propagate to the pre-shaping aperture A05. The pre-shaping aperture A05 further limits the diameter and position of the light beam to ensure that the light beam is calibrated along the center line. This step forms a calibrated light beam through precise beam limitation.

[0042] The spatial shaping unit 20 includes a spatial light modulator A12, which is configured to modulate and shape the calibrated light beam by adjusting the phase and amplitude of the pixels inside the spatial light modulator A12 to form a spatially shaped light beam.

[0043] In this embodiment, the spatial shaping unit 20 further includes a second mirror A11 and a third mirror A13. The second mirror A11 is configured to reflect the calibrated light beam to the spatial light modulator A12. The spatially shaped light beam after modulation and shaping by the spatial light modulator A12 is reflected by the third mirror A13 to the fourth mirror A14, and the fourth mirror A14 reflects the spatially shaped light beam to the time-domain shaping unit 30.

[0044] The specific working logic of the spatial domain shaping unit 20 is to precisely regulate and shape the spatial structure of the light beam through the collaborative action of a series of optical elements and the spatial light modulator A12. The calibration light beam first passes through the second mirror A11 and is reflected to the input surface of the spatial light modulator A12. The function of the second mirror A12 is to precisely guide the light beam to the spatial light modulator A12 and ensure that the light beam enters the spatial light modulator A12 at an appropriate angle and position.

[0045] After the light beam enters the spatial light modulator A12, the spatial light modulator A12 modulates and shapes the light beam by adjusting the phase and amplitude of its internal pixels. Specifically, each pixel of the spatial light modulator A12 can be independently controlled. By changing the phase and amplitude of the pixels, precise regulation of the light beam wavefront can be achieved. This process can change the spatial distribution, intensity distribution, and phase distribution of the light beam, thereby forming a spatially shaped light beam.

[0046] The spatially shaped light beam after being modulated and shaped by the spatial light modulator A12 is reflected by the third mirror A13 to the fourth mirror A14. The third mirror A13 ensures that the light beam is transmitted to the next step in the correct direction and position. Finally, the spatially shaped light beam is reflected by the fourth mirror A14 to the time domain shaping unit 30, providing a light beam with a precise spatial distribution for subsequent time domain processing. By modulating the phase and amplitude of the light beam, the spatial light modulator A12 can achieve precise control of the spatial distribution of the light beam, such as forming a uniform light spot or a specific light field distribution.

[0047] The flexibility of the spatial light modulator A12 enables the modulation and shaping of the light beam to be dynamically adjusted according to specific requirements. This means that in different experimental or application scenarios, multiple light beam shaping modes can be achieved, improving the adaptability and functional richness of the system. For example, for through-hole machining with a large depth-to-diameter ratio, Bessel beams are very suitable due to their long focal depth and self-healing characteristics. Such light beams can be achieved by adjusting the pixel phase of the spatial light modulator A12, enabling the effective transmission of laser energy to the deep part of the hole and improving the perpendicularity and machining quality of the hole wall. In machining tasks that require high surface uniformity, such as laser marking or thin film cutting, parallel light beams are suitable because of their uniform energy distribution, which can avoid overheating and non-uniformity. By adjusting the phase and amplitude of the SPM, the input light beam can be shaped into a parallel light beam, thereby improving the uniformity and quality of the machining surface. The dynamic adjustment ability of the spatial light modulator A12 makes it possible to quickly switch between multiple light beam modes in the same optical system, significantly improving the flexibility and efficiency of machining.

[0048] In this embodiment, by designing a reasonable optical path layout, the beam is accurately guided to the required position through the second mirror A11, the third mirror A13, and the fourth mirror A14. The precise positioning and angle adjustment of these mirrors ensure that the beam maintains good directivity and consistency throughout the shaping process. Through the above working logic and implementation method, the spatial shaping unit 20 can precisely control the spatial structure of the beam, providing a basis for subsequent optical processing and improving the overall performance and application effect of the system.

[0049] The time-domain shaping unit 30 includes a time-domain beam splitter A21 and a time-domain mirror A23 mounted on a guide rail A24. The spatially shaped beam is split into two beams by the time-domain beam splitter A41. One beam continues to propagate in the original direction, is reflected by the time-domain mirror A23, and is then reflected by the beam splitter A21 to form a time-domain shaped beam. The time-domain mirror adjusts the optical path by moving on the guide rail A24 to form an optical path difference for pulse delay.

[0050] The main function of the time-domain shaping unit 30 is to achieve pulse delay by adjusting the optical path, and then perform time-domain shaping on the beam. The beam after spatial shaping is split into two beams by the time-domain beam splitter A21. One beam continues to propagate in the original direction, and the other beam is reflected by the time-domain mirror A23. The time-domain mirror A23 is mounted on the guide rail A24 and can move along the guide rail. When the time-domain mirror A23 moves, it changes the path length that the beam needs to travel, thereby adjusting the optical path. The reflected beam is reflected back to the original direction by the beam splitter A21 and recombines with the directly propagating beam. The change in the optical path difference introduces pulse delay, thereby achieving time-domain shaping. By adjusting the optical path difference, the arrival time of the beam can be precisely controlled to achieve pulse delay. The delay adjustment of multiple pulses can make them overlap at the target position, thereby enhancing the optical effect or achieving specific coherent superposition. Precise optical path adjustment can make the time control in applications such as laser processing and communication more accurate.

[0051] The time-domain mirror adjusts the traveling path of the beam by moving on the guide rail A24. When the time-domain mirror moves along the guide rail, a beam split from the beam splitter A21 will be reflected by this mirror, changing its traveling distance. By precisely adjusting the position of the mirror, the path length of the beam can be increased or decreased, thereby introducing a controllable optical path difference. This optical path difference causes a delay of the beam on the time axis, achieving time-domain shaping of the pulse. In this way, the time when the beam reaches the target position can be precisely controlled to achieve pulse delay.

[0052] In this embodiment, the spatially shaped beam is split into two beams by the time-domain beam splitter A21. One beam continues to propagate in the original direction, and the other beam is reflected by the fifth mirror A22 to the birefringent crystal A41.

[0053] In this embodiment, the beam after spatial shaping is split into two beams by the time-domain beam splitter A21. One beam continues to propagate in the original direction, and the other beam is reflected by the fifth mirror A22 to the birefringent crystal A41. The beam after spatial shaping is split into two beams by the time-domain beam splitter A21. One beam, beam 1, continues to propagate in the original direction, and the other beam, beam 2, is reflected by the fifth mirror A22. The process of beam 2 being reflected by the fifth mirror A22 can achieve path turning and optical path adjustment. After being reflected, beam 2 enters the birefringent crystal A41. The birefringent crystal has different refractive indices, which can decompose the incident beam into two different polarization components and make them propagate along different paths, thereby introducing an optical path difference. By using the birefringent crystal A41, different optical path differences can be introduced to the different polarization components of beam 2, realizing pulse delay and separation. This is very beneficial for precisely controlling the time characteristics of the beam. The birefringent crystal A41 can modulate and control the polarization state of the beam, which helps to achieve more complex optical effects in subsequent applications, such as modulation and demodulation, polarization coding, etc.

[0054] The in-situ observation unit 50 includes a dichroic mirror A51 and an observation beam splitter A52. The illumination beam generated by the illumination device A53 passes through the observation beam splitter A52 and the dichroic mirror A51, and then converges at the same focus with the beam reflected by the dichroic mirror A51 from the time-domain shaped beam through the objective lens 61 for processing the sample on the three-dimensional precision displacement stage 62.

[0055] The illumination beam generated by the illumination device A53 first passes through the observation beam splitter A52, and then passes through the dichroic mirror A51. The time-domain shaped beam is reflected by the dichroic mirror A51 and then passes through the objective lens 61 together with the illumination beam. Under the action of the objective lens 61, the illumination beam and the time-domain shaped beam converge at the same focus. The beam converged by the objective lens 61 irradiates the sample on the three-dimensional precision displacement stage 62. During processing, the illumination light is used to observe the processing process in real time. The in-situ observation unit 50 allows the state of the sample to be observed in real time during processing. This is particularly important for precision machining because it provides immediate feedback, enabling timely adjustment of processing parameters to obtain the best results. Since the illumination beam and the time-domain shaped beam converge at the same focus, precise positioning of the processing area can be ensured, improving the processing accuracy.

[0056] In this embodiment, the optical axis of the objective lens 61 is coaxial with the beam of the illumination beam passing through the observation beam splitter A52 and the dichroic mirror A51 and the time-domain shaped beam reflected by the dichroic mirror A51. The in-situ observation unit 50 further includes a charge-coupled device A54. The beam reflected by the sample on the three-dimensional precision displacement stage 62 passes through the dichroic mirror A51 and is then reflected by the observation beam splitter A52 to the charge-coupled device A54, and the charge-coupled device A54 converts the received optical signal into an electrical signal.

[0057] The illumination beam plays a crucial role in the in-situ observation unit 50. It provides a light source that enables the sample to be clearly observed, ensuring the visualization of the sample. The illumination beam also helps to accurately locate specific areas of the sample, ensuring that the processing beam can act precisely on the target position. Through the real-time image acquisition and processing of the illumination beam, the operator can perform detailed quality control and optimize the processing parameters to ensure that the final product meets the design requirements. The synchronization control system coordinates the movement of the illumination device, the beam transmission path, and the three-dimensional precision displacement stage 62 to achieve synchronous processing and observation, thereby improving the safety and efficiency of the processing process.

[0058] The illumination beam generated by the illumination device passes through the observation beam splitter and the dichroic mirror, and then the beam reflected by the dichroic mirror of the time-domain shaping beam is input into the vacuum processing unit 60. The vacuum processing unit 60 includes an objective lens 61 and a three-dimensional precision displacement stage 62. The beam output from the in-situ observation unit 50 is converged at the same focal point through the objective lens 61 to process the sample on the three-dimensional precision displacement stage 62.

[0059] In this embodiment, the optical axis of the objective lens 61 is coaxial with the beam of the illumination beam passing through the observation beam splitter A52 and the dichroic mirror A51, and the time-domain shaping beam reflected by the dichroic mirror A51. This design ensures that the illumination beam and the time-domain shaping beam can accurately irradiate the sample on the three-dimensional precision displacement stage 62 through the objective lens 61, thereby achieving precise sample observation and processing. When the illumination beam and the time-domain shaping beam irradiate the sample, the sample will reflect a part of the beam. The reflected beam passes through the objective lens 61 again, and through the dichroic mirror A51 and the observation beam splitter A52, it is guided to the charge-coupled device A54. The observation beam splitter A52 plays an important role in this process. It directs the reflected beam to the charge-coupled device A54.

[0060] The charge-coupled device A54 receives the optical signals reflected by the sample and converts these optical signals into electrical signals. These electrical signals are used to generate an image of the sample in real time, providing immediate feedback information. Through this efficient optical path design and signal processing logic, the system can achieve high-precision monitoring of the processing process, optimize the processing parameters, and improve the quality and consistency of the final product.

[0061] Further, the time-domain shaping beam is incident on the in-situ observation unit 50 through the calibration unit 40. The calibration unit 40 includes two calibration apertures A33 and A34 with the same center height. The time-domain shaping beam passes through the two calibration apertures A33 and A34 and then is incident on the dichroic mirror A51. The two calibration apertures A33 and A34 are used to limit the diameter and position of the time-domain shaping beam to ensure that the beam is calibrated along the center of the calibration apertures A33 and A34.

[0062] The working logic of the calibration unit 40 starts with the generation and transmission of a time-domain shaped beam. This beam passes through two calibration diaphragms A33 and A34 with their centers at the same height and enters the in-situ observation unit 50. The first calibration diaphragm A33 limits the diameter of the beam, making the spatial distribution of the beam more concentrated. Then the beam passes through the second calibration diaphragm A34 to further ensure that the position and diameter of the beam remain consistent. Through the precise calibration of these two calibration diaphragms, the time-domain shaped beam is transmitted along the center of the diaphragms and finally enters the dichroic mirror A51 for subsequent optical path transmission and sample irradiation. The calibration process significantly improves the collimation and stability of the time-domain shaped beam, ensuring high-precision transmission and sample irradiation in the subsequent optical path. Through the limitation of the two calibration diaphragms, the diameter and position of the beam are precisely controlled, enabling the beam to always be transmitted along the center of the diaphragms, thus avoiding beam deviation and enhancing the overall stability and consistency of the system. The calibration unit 40 precisely calibrates the time-domain shaped beam when it passes through the calibration diaphragms through precise design and installation of the two diaphragms, ensuring the processing precision and observation precision of the system. By monitoring the transmission of the beam through laser calibration and imaging technology, it is further ensured that the beam does not deviate during the calibration process, thereby improving the beam quality of the entire system and the final technical effect.

[0063] The calibration unit 40 further includes a sixth mirror A31 and a seventh mirror A32. The time-domain shaped beam is reflected by the sixth mirror A31 to the seventh mirror A32, and the seventh mirror A32 reflects the time-domain shaped beam to the centers of the calibration diaphragms A33 and A34.

[0064] After the time-domain shaped beam is generated, it first passes through the sixth mirror A31. The function of the sixth mirror A31 is to change the transmission direction of the beam so that it can be precisely reflected to the seventh mirror A32. By precisely adjusting the position and angle of the sixth mirror A31, it is ensured that the time-domain shaped beam can accurately hit the seventh mirror A32. The seventh mirror A32 receives the beam reflected from the sixth mirror A31 and adjusts the transmission direction of the beam again so that it can precisely enter the center positions of the calibration diaphragms A33 and A34. Through precise angle and position adjustment, the seventh mirror A32 ensures that the time-domain shaped beam can be transmitted along the designed optical path and precisely pass through the calibration diaphragms A33 and A34.

[0065] Through the double reflection adjustment of the sixth mirror A31 and the seventh mirror A32, the time-domain shaped beam can be accurately positioned and collimated, ensuring that when it enters the calibration diaphragms A33 and A34, the diameter and position of the beam are precisely limited and calibrated. Finally, the time-domain shaped beam passing through the calibration diaphragms enters the dichroic mirror A51 for subsequent optical path transmission and sample irradiation, thereby achieving high-precision optical calibration and stable beam transmission.

[0066] In this embodiment, the vacuum processing unit 60 is fixed inside the vacuum processing chamber 70. The vacuum processing chamber 70 includes a cylindrical cavity 71 with an internal vacuum. The cavity 71 has a quartz window made of fused quartz. The light beam output by the in-situ observation unit 50 enters the interior of the cavity 71 through the quartz window. At the bottom of the cavity 71, there is an optical platform 72. A three-dimensional precision displacement stage 62 is installed on the optical platform 72. The objective lens 61 is located at the upper end of the three-dimensional precision displacement stage 62. An objective lens adjustment manipulator 63 is fixed on the cavity 71. The objective lens adjustment manipulator 63 passes through the cavity 71 and is connected to the objective lens 61 through a rotary feedthrough. The vacuum processing unit 60 further includes the objective lens adjustment manipulator 63. The objective lens adjustment manipulator 63 is connected to the objective lens 61 through a rotary feedthrough, enabling the objective lens 61 to perform three-axis movement. The objective lens 61 is located at the upper end of the three-dimensional precision displacement stage 62. An objective lens adjustment manipulator 63 is fixed on the cavity 71. The objective lens adjustment manipulator 63 passes through the cavity 71 and is connected to the objective lens 61 through a rotary feedthrough.

[0067] A rotary feedthrough is a mechanical device designed to move in a vacuum environment and can transfer rotational and linear motion. It is used for precise mechanical motion in an isolated vacuum environment. A rotary feedthrough is a component for transmitting mechanical motion between the inside and outside of a vacuum chamber, used to transfer external mechanical motion into the interior of the vacuum chamber. One end of the rotary feedthrough passes through the vacuum chamber and is connected to the objective lens adjustment manipulator, while the other end is connected to the objective lens. Through this connection method, external motion can be transmitted to the objective lens to achieve its movement and adjustment in a vacuum environment. The main function of the rotary feedthrough is to transfer external control signals and motion into the interior of the vacuum chamber to achieve rotational and linear movement of the objective lens, enabling precise mechanical adjustment in a vacuum environment without disrupting the vacuum conditions. The objective lens adjustment manipulator utilizes the motion capabilities provided by the rotary feedthrough to perform precise three-axis movement and angular adjustment of the objective lens. The manipulator is equipped with motors and sensors for precise control of the objective lens position.

[0068] The vacuum processing chamber 70 is a core component that includes a cylindrical cavity 71. This cavity is designed to maintain an ultra-high vacuum state to provide a clean and environmentally unaffected processing environment. On one side of the cavity, there is a quartz window made of fused quartz. This window can not only withstand the vacuum pressure but also has good optical transparency, allowing external light beams to accurately enter the interior of the cavity without affecting the vacuum environment for the optical system used in precision processing.

[0069] An optical platform 72 is provided at the bottom of the cavity, which provides a stable foundation for the optical components of the system. A three-dimensional precision displacement stage 62 is assembled on the platform. This displacement stage can move precisely in three dimensions to ensure that the sample is always in the optimal processing position. An objective lens 61 is installed above the displacement stage. This objective lens is responsible for focusing the incoming light beam onto the sample to achieve fine processing of the material.

[0070] Optical platforms and three-dimensional precision displacement stages are commonly used components in precision optical and mechanical systems and are widely used in laboratory and industrial environments. An optical platform is a stable base for fixing and supporting optical components. Optical platforms are widely used in laser experiments, optical measurements, and optoelectronic device assembly. They provide a stable environment so that the optical path can maintain precise alignment. A three-dimensional precision displacement stage is a mechanical device for precisely positioning and moving objects and can move in three different directions. The three-dimensional precision displacement stage can be equipped with different types of drive systems, including manual adjustment, stepper motor drive, or piezoelectric motor drive. The electronic control system can achieve precise control of the displacement stage for automated operation and precise positioning.

[0071] Furthermore, three layers of flange ports for connection are provided on the cavity 71. An observation window 73 is provided on the upper flange port. The middle flange port is hermetically connected to an in-situ AFM characterization window 74 and a quick-opening window 75. The in-situ AFM characterization window 74 is used to observe the processing quality inside the cavity 71 in-situ. The bottom flange port is hermetically connected to an electrode 76, a vacuum gauge 77, a micro-leak valve 78, and a molecular pump 79. The electrode 76 is electrically connected to the optical platform 72 and the three-dimensional precision displacement stage and is used to supply power to the optical platform 72 and the three-dimensional precision displacement stage 62. The vacuum gauge 77 is used to measure the internal pressure of the cavity 71. The micro-leak valve 78 is used to relieve the pressure of the cavity 71. A gate valve is also provided on the cavity 71 for interconnection with other vacuum chambers.

[0072] The cavity 71 is designed with multiple layers of flange ports to meet the connection requirements of different functional components. Each layer of flange port undertakes specific functions to ensure that the cavity can operate efficiently under vacuum conditions, while supporting a variety of precision machining and observation operations. An observation window 73 is installed on the first layer of flange port. This is an optical window made of a high-strength transparent material, using quartz or sapphire glass. The role of the observation window is to allow external personnel to directly observe the internal situation of the cavity through optical means. Since the vacuum environment requires a high degree of sealing, the observation window must have excellent sealing performance and pressure resistance to ensure that it does not affect the vacuum state of the cavity. The use of high light transmittance materials ensures the clarity of optical observation. The middle layer flange port is hermetically connected to the in-situ AFM characterization window 74 and the quick-opening window 75. The in-situ AFM characterization window is a dedicated interface designed for atomic force microscope observation. It allows real-time monitoring and characterization of the surface quality of processed samples under vacuum conditions. The AFM window needs to have excellent sealing performance and anti-interference ability to ensure the accuracy of the AFM probe. The quick-opening window provides a convenient access point, allowing the cavity to be quickly opened for sample replacement or equipment maintenance. Its design needs to ensure fast operation without affecting the vacuum integrity.

[0073] The bottom layer flange port is connected to the electrode 76, vacuum gauge 77, micro-leak valve 78 and molecular pump 79. The electrode 76 is electrically connected to the optical platform 72 and the three-dimensional precision displacement stage, providing the necessary electrical support to drive the displacement stage and other electric components. The vacuum gauge 77 is used to measure the pressure level inside the cavity to ensure that the vacuum environment meets the processing and observation requirements. Accurate pressure measurement is crucial for maintaining stable processing conditions. The micro-leak valve 78 is used to control the pressure relief process of the cavity. This valve is designed to slowly release the pressure inside the cavity under precise control, so as to achieve safe pressure relief without damaging precision equipment. The molecular pump 79 is one of the core devices for maintaining the ultra-high vacuum state of the cavity. It pumps out gas molecules inside the cavity through high-speed rotation to achieve an extremely low pressure environment and ensure that the processing process is not interfered by gas.

[0074] A gate valve is also equipped on the cavity 71 for interconnection with other vacuum chambers. The gate valve is a valve that can be quickly opened or closed, usually used to isolate or connect different vacuum chamber segments. Through strict sealing and pressure resistance design, the gate valve ensures the overall vacuum level of the system while allowing complex experimental configurations and modular operations.

[0075] The ultra-high vacuum processing cavity and the gas source equipment are key components in precision material processing. First of all, the main function of the ultra-high vacuum processing cavity is to pump out the gas inside the cavity through an efficient vacuum pump system, such as a turbomolecular pump and an ion pump, to achieve an ultra-high vacuum state. The cavity is usually made of stainless steel or aluminum alloy to ensure the purity of the internal environment and isolate external interference, thereby reducing the impact of impurities in the air on the processing process.

[0076] Secondly, in an ultra-high vacuum environment, the reactions between the material surface and chemical components such as oxygen in the outside world are greatly reduced. This environment avoids unnecessary oxidation or modification, making material processing more pure and precise, and is particularly suitable for processes that require a high degree of cleanliness, such as semiconductor manufacturing and surface science research.

[0077] The gas source equipment introduces specific gases into the processing chamber through precise pipelines and control valves. The gas source equipment can precisely adjust the gas pressure and composition in the chamber to ensure that different process requirements are met. This feature allows for effective control of the atmosphere in the chamber during material processing, supporting diverse processing goals.

[0078] Finally, by combining the use of an ultra-high vacuum processing chamber and gas source equipment, high-purity and high-precision environmental control can be achieved during processing. Different types of gases can be introduced into the chamber as needed to achieve specific material modification effects, such as forming a protective layer or a specific compound, providing extensive flexibility and possibilities for advanced manufacturing and research.

[0079] Based on the coupling of an ultra-high vacuum processing system with spatio-temporal-frequency shaping of femtosecond lasers and an ultra-high vacuum processing chamber, the high-precision advantages of the laser after spatio-temporal-frequency shaping can be further amplified. The ultra-high vacuum environment provides an extremely pure and controllable processing space, greatly reducing the interference of dust, moisture, and other impurities in the air on the processing process, thereby achieving higher-quality processing. In this environment, the interaction between the laser and the material will not cause oxidation or other modification reactions on the material surface, which is particularly important for the processing of metal thin film products and lithium batteries that require a high degree of material purity. In addition, the ultra-high vacuum environment helps to effectively remove the debris and plasma generated during the processing, maintaining the consistency of the processing process and being unaffected by the laser energy deflection and loss caused by these factors.

[0080] By connecting to a specific gas source, the ultra-high vacuum environment can achieve precise control of the atmosphere, air pressure, and element ratio within the system, which provides the necessary conditions for sample processing that requires a specific air pressure environment. At the same time, for metal thin films such as sulfides, oxides, and nitrides, this environment can effectively protect the material and endow it with specific optical, chemical, and physical properties. By precisely regulating the element ratio of the atmosphere within the system and supplemented by the adjustment of the thermal field and electric field, a customized thin film can be formed in the processing area when laser processing a specific structure, thus providing diverse material modification methods for spatio-temporal-frequency femtosecond laser processing.

[0081] Importantly, it should be noted that the construction and arrangement of the present application shown in multiple different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who refer to this disclosure should easily understand that many modifications are possible without materially departing from the novel teachings and advantages of the subject matter described in this application (e.g., changes in the dimensions, scales, structures, shapes and proportions of various elements, as well as parameter values (such as temperature, pressure, etc.), installation arrangements, use of materials, colors, orientations, etc.). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature, number or position of discrete elements may be altered or changed. Accordingly, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be altered or reordered according to alternative embodiments. In the claims, any "means plus function" clause is intended to cover the structures that perform the recited function herein, and not only structural equivalents but also equivalent structures. Other substitutions, improvements, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present invention. Accordingly, the present invention is not limited to a particular embodiment, but extends to various modifications that still fall within the scope of the appended claims.

[0082] In addition, in order to provide a concise description of the exemplary embodiments, all features of the actual embodiments may not be described (i.e., those features that are not relevant to the currently contemplated best mode of carrying out the present invention, or those features that are not relevant to implementing the present invention).

[0083] It should be understood that in the development of any actual implementation, as in any engineering or design project, numerous specific implementation decisions may be made. Such development efforts may be complex and time-consuming, but for those of ordinary skill in the art who benefit from this disclosure, the development efforts will be a routine task of design, fabrication and production without undue experimentation.

[0084] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. An ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping, comprising a femtosecond laser, characterized in that: A pre-shaping unit, a spatial domain shaping unit, a temporal domain shaping unit and an in-situ observation unit are sequentially arranged on the optical path of the femtosecond laser output by the femtosecond laser; The pre-shaping unit is used to weaken the intensity of the light beam to control the energy level, and to limit the diameter and position of the light beam to ensure that the light beam is calibrated along the center to form a calibrated light beam; The spatial shaping unit includes a spatial light modulator, which is used to modulate and shape the calibration light beam by adjusting the phase and amplitude of the pixels inside the spatial light modulator to form a spatially shaped light beam; The time domain shaping unit includes a time domain beam splitter and a time domain reflector mounted on a guide rail, the spatial domain shaping light beam is split into two light beams by the time domain beam splitter, one of the light beams continues to propagate in the original direction, is reflected by the time domain reflector, and is reflected by the beam splitter to form a time domain shaping light beam, the time domain reflector adjusts the optical path by moving on the guide rail, and forms an optical path difference to achieve pulse delay; The in-situ observation unit comprises a dichroic mirror and an observation beam splitter. After the illumination light beam generated by the illumination device passes through the observation beam splitter and the dichroic mirror, the light beam and the time-domain shaping light beam are reflected by the dichroic mirror and input into the vacuum processing unit. The vacuum processing unit comprises an objective lens and a three-dimensional precision translation stage. The light beams output by the in-situ observation unit converge at the same focus through the objective lens to process the sample on the three-dimensional precision translation stage.

2. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 1, characterized in that: The pre-shaping unit includes a beam splitter, an attenuation plate and two pre-shaping apertures. The femtosecond laser is split into multiple light beams by the beam splitter, wherein one light beam passes through the attenuation plate and the center of the two pre-shaping apertures, the attenuation plate and the center of the two pre-shaping apertures are located at the same height, and the attenuation plate is located between the two pre-shaping apertures. The attenuation plate is used to weaken the intensity of the light beam to control the energy level, and the pre-shaping aperture is used to limit the diameter and position of the light beam to ensure that the light beam is calibrated along the center of the pre-shaping aperture to form a calibrated light beam. The pre-shaping unit also includes a first reflector, which is used to reflect one of the light beams split by the beam splitter to the center of the pre-shaping aperture.

3. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 1, characterized in that: The spatial domain shaping unit also includes a second reflector and a third reflector, the second reflector is used to reflect the calibration light beam to the spatial light modulator, the spatial domain shaped light beam modulated and shaped by the spatial light modulator is reflected to the fourth reflector through the third reflector, and the fourth reflector reflects the spatial domain shaped light beam to the time domain shaping unit.

4. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 3, characterized in that: The spatially shaped beam is split into two beams by a time-domain beam splitter, one of which continues to propagate in the original direction, and the other is reflected to a birefringent crystal by a fifth reflector.

5. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 1, characterized in that: The time domain shaped light beam is incident on the in-situ observation unit through a calibration unit, and the calibration unit includes two calibration diaphragms whose centers are located at the same height. The time domain shaped light beam is incident on the dichroic mirror after passing through the two calibration diaphragms. The two calibration diaphragms are used to limit the diameter and position of the time domain shaped light beam to ensure that the light beam is calibrated along the center of the calibration diaphragm.

6. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 5, characterized in that: The calibration unit also includes a sixth reflector and a seventh reflector. The time domain shaped light beam is reflected to the seventh reflector through the sixth reflector, and the seventh reflector reflects the time domain shaped light beam to the center of the calibration aperture.

7. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 1, characterized in that: The optical axis of the objective lens is coaxial with the light beam after the illumination light beam passes through the observation beam splitter and the dichroic mirror, and the time-domain shaped light beam reflected by the dichroic mirror. The in-situ observation unit also includes a charge-coupled device. The light beam reflected by the sample on the three-dimensional precision translation stage passes through the dichroic mirror and is reflected to the charge-coupled device through the observation beam splitter. The charge-coupled device converts the received light signal into an electrical signal.

8. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 1, characterized in that: The vacuum processing unit also includes an objective lens adjustment robot, which is connected to the objective lens through a rotating introducer so that the objective lens can move in three axes. The vacuum processing unit is fixed in a vacuum processing chamber, which includes a cylindrical cavity with internal vacuum. The cavity has a quartz window made of fused quartz. The light beam output by the in-situ observation unit enters the cavity through the quartz window. An optical platform is provided at the bottom of the cavity, and a three-dimensional precision displacement stage is installed on the optical platform. The objective lens is located at the upper end of the three-dimensional precision displacement stage. An objective lens adjustment robot is fixed on the cavity, and the objective lens adjustment robot passes through the cavity and is connected to the objective lens through the rotating introducer.

9. The ultra-high vacuum processing system based on femtosecond laser spatiotemporal frequency shaping according to claim 8, characterized in that: The cavity is provided with three layers of flanges for connection, wherein the upper flange is provided with an observation window, the middle flange is sealed with an in-situ AFM characterization window and a quick-opening window, the in-situ AFM characterization window is used to in-situ observe the processing quality inside the cavity, the bottom flange is sealed with electrodes, a vacuum gauge, a micro-leakage valve and a molecular pump, the electrodes are electrically connected to the optical platform and the three-dimensional precision translation stage, and are used to power the optical platform and the three-dimensional precision translation stage, the vacuum gauge is used to measure the internal pressure of the cavity, the micro-leakage valve is used to relieve the pressure of the cavity, and the cavity is also provided with a gate valve for interconnection with other vacuum chamber bodies.

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