Super pulse laser output system and method

Abstract

The invention provides an ultra-pulse laser output system and method, and the system comprises an FPGA control module, an ultra-fast laser source, a long / short pulse laser source, a beam combining module, a first electric zoom beam expander and a second electric zoom beam expander, and the long / short pulse laser source enters the beam combining module through the second electric zoom beam expander; the ultrafast laser source is incident to the beam combining module through the first electric zoom beam expander; the super-pulse laser output by the beam combining module is focused on the surface of a workpiece; the FPGA control module is in control connection with the ultrafast laser source, the long / short pulse laser source, the first electric zoom beam expander and the second electric zoom beam expander. The problems that according to an existing composite laser technology, light beam alignment is difficult, time sequence regulation and control accuracy is poor, and stability is insufficient are solved.

Description

Technical Field

[0001] The present invention belongs to the fields of lasers and manufacturing, and particularly relates to an ultra-pulse laser output system and method. Background Art

[0002] According to the pulse width, lasers can be divided into long-pulse lasers (including continuous lasers), short-pulse lasers, and ultrafast lasers. Among them, long / short-pulse lasers rely on thermal effects for processing, while due to the extremely short action time characteristics, ultrafast lasers can achieve "cold" processing with extremely low thermal influence. Therefore, lasers have a wide range of applications in the field of manufacturing.

[0003] However, there are certain defects in the current two laser processing methods. Due to the low average power of current ultrafast lasers, their processing efficiency is limited, so they are less used in actual applications. And as the average power of ultrafast lasers increases, the thermal effect also begins to be significant. The widely used long / short-pulse lasers have extremely high processing efficiency, but there are serious thermal effects in their processing process, and the processing quality is limited. Therefore, in the current laser processing applications, it is difficult to balance the contradiction between processing quality and processing efficiency.

[0004] In addition, a single type of laser is difficult to achieve the coordination of "cold" and "hot" effects in some special applications such as material synthesis, and it cannot take into account the usage characteristics of both lasers.

[0005] To solve the above problems, the compound laser technology is proposed, which combines two or more lasers with different pulse widths to integrate the advantages of different pulse width lasers and achieve the coordination of "cold" and "hot" effects. However, the current compound laser technology still has various problems such as difficult beam alignment, poor timing control accuracy, and insufficient stability, and cannot be effectively applied in practice, which limits the development of the compound laser technology. Summary of the Invention

[0006] The purpose of the present invention is to provide an ultra-pulse laser output system and method, which solves the problems of difficult beam alignment, poor timing control accuracy, and insufficient stability existing in the existing compound laser technology.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is: An ultra-pulse laser output system and method provided by the present invention includes an FPGA control module, an ultrafast laser source, a long / short pulse laser source, a beam combining module, a first motorized variable magnification beam expander, and a second motorized variable magnification beam expander, wherein: The long / short pulse laser source is incident on the beam combining module through the second motorized variable magnification beam expander; The ultrafast laser source is incident on the beam combining module through the first motorized variable magnification beam expander; The ultra-pulse laser output by the beam combining module is focused on the surface of the workpiece; The FPGA control module is respectively connected to the ultrafast laser source, the long / short pulse laser source, the first motorized variable magnification beam expander, and the second motorized variable magnification beam expander for control.

[0008] Preferably, the long / short pulse laser source is incident on the second motorized variable magnification beam expander through a mirror; a beam auto-collimation module is arranged between the second motorized variable magnification beam expander and the beam combining module, and the beam auto-collimation module is connected to the FPGA control module for control.

[0009] Preferably, the beam auto-collimation module includes a first motorized mirror and a second motorized mirror, wherein the first motorized mirror and the second motorized mirror are arranged symmetrically by mirror image.

[0010] Preferably, a part of the ultra-pulse laser output by the beam combining module is incident on a real-time monitoring module for obtaining the beam alignment deviation value between two expanded beams in the ultra-pulse laser, and the real-time monitoring module is connected to the FPGA control module for control.

[0011] Preferably, the real-time monitoring module includes a beam splitter, a high-speed photodetector, and a camera module, wherein the ultra-pulse laser output by the beam combining module is incident on the beam splitter, one of the two ultra-pulse lasers output by the beam splitter is incident on the high-speed photodetector, and the other ultra-pulse laser is incident on the camera module.

[0012] Preferably, the beam combining module includes two λ / 2 wave plates and a polarization beam splitter, wherein the two λ / 2 wave plates are vertically placed at 90° with the polarization beam splitter as the center, the beam output by the beam auto-collimation module is incident on one of the λ / 2 wave plates, the beam of the first motorized mirror is incident on the other λ / 2 wave plate, and the beams output by the two λ / 2 wave plates are both incident on the polarization beam splitter.

[0013] Preferably, the FPGA control module includes a signal and image acquisition sub-unit, a signal and image processing sub-unit, a signal input / output control sub-unit, and a device control sub-unit, wherein: The input end of the signal and image acquisition sub-unit is connected to the output end of the real-time monitoring module for acquiring optoelectronic signals and image data; The signal and image processing sub-unit is used for extracting the beam delay deviation value and the beam alignment deviation value from the received optoelectronic signals and image data; The signal input / output control sub-unit is used for controlling the timing relationship between the ultrafast laser and the long / short pulse laser, and controlling the parameters of the ultrafast laser source and the long / short pulse laser source; The device control sub-unit is respectively connected to the beam auto-collimation module, the first motorized variable magnification beam expander, and the second motorized variable magnification beam expander for controlling the beam diameter and the coaxiality of the two laser beams.

[0014] Preferably, the ultrafast pulse source is a laser with a pulse width of 0 fs - 10 ps, and the long / short pulse laser is a laser with a pulse width between 0 ns and 100 ms.

[0015] A method for outputting super-pulse laser, based on the super-pulse laser output system described above, includes the following steps: Set the timing delay between two adjacent super-pulse lasers; Set the initial repetition frequency, pulse energy, pulse width, and number of pulses corresponding to the ultrafast laser source and the long / short pulse laser source within the duration of each super-pulse laser; Set the timing delay between the ultrafast laser source and the long / short pulse laser source within the duration of each super-pulse laser; Respectively set the start trigger times of the ultrafast laser source and the long / short pulse laser source within the duration of each super-pulse laser; Turn on the ultrafast laser light source and the long / short pulse laser light source; Respectively perform variable magnification beam expansion on the beam diameters of the emitted ultrafast laser and long / short pulse laser to obtain two expanded laser beams; Combine the two obtained expanded laser beams to obtain a super-pulse laser, and the super-pulse laser is focused on the surface of the workpiece.

[0016] Preferably, the method further includes: obtaining in real time the beam alignment deviation value between the two expanded laser beams in the super-pulse laser, and using the beam alignment deviation value to adjust the coaxiality between the ultrafast laser and the long / short pulse laser.

[0017] Compared with the prior art, the beneficial effects of the present invention are: A super-pulse laser output system provided by the present invention expands the ultrafast laser and the long / short pulse laser respectively, and combines them after expansion to form a super-pulse laser. The super-pulse laser formed by this method can freely adjust the ratio of the two beam diameters, and parameters such as the beam diameter ratio, number of pulses, pulse delay, and pulse energy ratio of the formed super-pulse laser can all be freely adjusted. At the same time, it can achieve the synergistic laser material interaction of "cold" and "hot" effects, and solves the problems of difficult beam alignment, poor timing control accuracy, and insufficient stability existing in the existing composite laser technology.

[0018] Furthermore, the purpose of adding a reflector between the long / short pulse laser light source and the second motorized variable magnification beam expander is to ensure that the beam direction can enter the beam combination module according to the preset trajectory.

[0019] Further, a beam auto - collimation module is provided between the second electrically variable magnification beam expander and the beam combining module. Since the ultrafast laser belongs to fixed - optical - path transmission and serves as a reference, while the long / short - pulse laser belongs to adjustable - beam transmission, with the reference as a guide, the beam auto - collimation module is used to adjust the transmission direction of the long / short - pulse laser to ensure the coaxiality between the long / short - pulse laser and the ultrafast laser.

[0020] Further, the purpose of setting the real - time monitoring module is to obtain the beam alignment deviation value between the long / short - pulse laser and the ultrafast laser in real time, and use the beam alignment deviation value to adjust the beam direction of the long / short - pulse laser to ensure that the centers of the two light spots completely coincide, thereby ensuring the coaxiality between the long / short - pulse laser and the ultrafast laser. Description of the Drawings

[0021] Figure 1 is the general flowchart of the method of the embodiment of the present invention; Figure 2 is the flowchart of the method for internal laser beam combining of the super - pulse in the embodiment of the present invention; Figure 3 is the diagram of the correspondence between the internal laser parameters of the super - pulse and the external signals in the embodiment of the present invention; Figure 4 is the flowchart of the method for regulating the super - pulse timing delay and action time in the embodiment of the present invention; Figure 5 is the regulation of the super - pulse timing delay and action time in the embodiment of the present invention; Figure 6 is the flowchart of the method for monitoring the super - pulse by a high - speed optoelectronic detector in the embodiment of the present invention; Figure 7 is the overall system diagram of the super - pulse output in the embodiment of the present invention; Figure 8 is the sub - unit and interface diagram of the FPGA control module in the embodiment of the present invention; Figure 9 is the super - pulse laser diagram output in the embodiment 4 of the present invention; Figure 10 is the super - pulse laser diagram output in the embodiment 5 of the present invention; Figure 11 is the super - pulse laser diagram output in the embodiment 6 of the present invention. Detailed Embodiments

[0022] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well - known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0023] It should be understood that, as used in the specification of this application and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or their combinations.

[0024] It should also be understood that the term "and / or" used in the specification of this application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0025] As used in the specification of this application and the appended claims, the term "if" may be construed, depending on the context, as "when" or "once" or "in response to determining" or "in response to detecting". Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be construed, depending on the context, as meaning "once determined" or "in response to determining" or "once [the described condition or event] is detected" or "in response to detecting [the described condition or event]".

[0026] In addition, in the description of the specification of this application and the appended claims, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0027] Reference to "one embodiment" or "some embodiments" or the like described in the specification of this application means that a specific feature, structure or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0028] Embodiment 1 As Figure 7 shown, a super-pulse laser output system provided in this embodiment includes an FPGA control module 1, an ultrafast laser source 2, a long / short pulse laser source 3, a beam auto-collimation module 4, a beam combining module 5, a real-time monitoring module 6, a first motorized variable magnification beam expander 7, a reflector 8, and a second motorized variable magnification beam expander 9, where: The long / short pulse laser source 3 is incident on the beam autocollimation module 4 through the mirror 8 and the second motorized variable magnification beam expander 9, and the light source output by the beam autocollimation module 4 is incident on the beam combining module 5.

[0029] The ultrafast laser source 2 is incident on the beam combining module 5 after passing through the first motorized variable magnification beam expander 7.

[0030] The combined superpulse output by the beam combining module 5 is divided into two parts, one part is incident on an external device, and the other part is incident on the real-time monitoring module 6 for monitoring the beam alignment situation and the timing relationship.

[0031] The ultrafast laser source 2, the long / short pulse laser source 3, the beam autocollimation module 4, the real-time monitoring module 6, the first motorized variable magnification beam expander 7 and the second motorized variable magnification beam expander 9 are all controlled and connected to the FPGA control module 1.

[0032] The ultrafast pulse source 2 is a laser with a pulse width of 0 fs - 10 ps, and the long / short pulse laser is a laser with a pulse width between 0 ns and 100 ms.

[0033] The beam autocollimation module 4 includes a first motorized mirror 10 and a second motorized mirror 11. Among them, the first motorized mirror 10 and the second motorized mirror 11 are arranged symmetrically. The motorized mirror can automatically adjust the beam deflection direction according to the beam alignment situation, so that the long / short pulse laser and the ultrafast laser always maintain coaxial output.

[0034] The motorized variable magnification beam expander can respectively control the incident spot sizes of the ultrafast pulse and the long / short pulse laser, so as to realize the output of the superpulse laser with any spot ratio size, and the variable magnification range is 1x - 6x.

[0035] The beam combining module 5 includes two λ / 2 wave plates (13, 14) and a polarization beam splitter. Among them, the two λ / 2 wave plates are vertically placed at 90 degrees with the polarization beam splitter as the center. The ultrafast laser and the long / short pulse laser are respectively incident on the polarization beam splitter 12 from the two λ / 2 wave plates (13, 14), and the polarization directions of the two lasers can be adjusted respectively by rotating the λ / 2 wave plates.

[0036] The real-time monitoring module 6 includes a beam splitter 15, a high-speed photodetector 16 and a camera module 17. Among them, the superpulse laser output by the beam combining module is incident on the beam splitter 15 and is divided into two beams of superpulse laser. One beam of superpulse laser is incident on the high-speed photodetector, and the other beam of laser is incident on the camera module.

[0037] The high-speed photodetector is used to monitor the timing relationship between the ultrafast pulse and the long / short pulse laser inside the superpulse laser and between the superpulses.

[0038] The camera module is used to monitor the coaxial alignment degree between the ultrafast pulsed laser and the long / short pulsed laser, so as to be used as the feedback value of the automatic alignment module.

[0039] As Figure 8 shown, the FPGA control module includes a signal and image acquisition sub-unit, a signal and image processing sub-unit, a signal input / output control sub-unit, a device control sub-unit, and a feedback control sub-unit, where: The signal and image acquisition unit sub-unit includes a signal acquisition interface and an image acquisition interface, and is used to acquire the photoelectric signals of the high-speed photodetector and the image data of the camera module.

[0040] The signal and image processing sub-unit is used to perform real-time processing and display on the photodetector signals, and is also used to process the image data to extract the beam delay deviation value and the beam alignment deviation value.

[0041] The output end of the signal and image processing sub-unit is connected to the device control sub-unit through the feedback control sub-unit, so as to feedback the extracted beam alignment deviation value to the device control sub-unit.

[0042] The signal input / output control sub-unit includes a signal synchronous output interface, an analog / digital signal output interface, and an external synchronous signal input interface. Among them, the synchronous signal output interface is used to synchronize the timing relationship of external devices, especially to synchronize the timing relationship between the ultrafast laser and the long / short pulsed laser; the analog / digital signal output interface is used to control the laser parameters and to control external devices; the external synchronous signal input interface is used to synchronize the system with external devices and trigger the ultra-pulsed laser processing system using external signals.

[0043] The device control sub-unit includes an electric variable magnification beam expander control signal output interface and an electric mirror control signal output interface. Among them, the electric variable magnification beam expander control signal output interface is respectively connected to the first electric variable magnification beam expander and the second electric variable magnification beam expander for control; the electric mirror control signal output interface is connected to the first electric mirror and the second electric mirror for control.

[0044] The cooperation between the device control sub-unit and the feedback control sub-unit is used to control the beam self-alignment module, the electric variable magnification beam expander, and the feedback control, etc., so as to realize the automatic adjustment of the ultra-pulse coaxiality, the adaptive adjustment of the energy / beam ratio, and the precise control of the signal output delay.

[0045] Embodiment 2 A method for outputting an ultra-pulsed laser provided in this embodiment includes the following steps: Set the timing delay between two adjacent ultra-pulsed lasers; Set the initial repetition frequency, pulse energy, pulse width, and number of pulses corresponding to the ultrafast laser source and the long / short pulse laser source within each super-pulse laser duration; Set the timing delay between the ultrafast laser source and the long / short pulse laser source within each super-pulse laser duration; Set the start trigger times of the ultrafast laser source and the long / short pulse laser source within each super-pulse laser duration respectively; Turn on the ultrafast laser light source and the long / short pulse laser light source; Respectively perform beam magnification and beam expansion on the beam diameters of the emitted ultrafast laser and long / short pulse laser to obtain two expanded laser beams; Combine the two obtained expanded laser beams to obtain a super-pulse laser; Obtain the beam alignment deviation value between the two expanded laser beams in the super-pulse laser, and use the beam alignment deviation value to adjust the coaxiality between the ultrafast laser and the long / short pulse laser.

[0046] Embodiment 3 Based on Embodiment 2, a method for outputting a super-pulse laser provided in this embodiment is as follows Figure 2 As shown, use a beam combining module to combine the ultrafast laser and the long / short pulse laser, and combine a beam automatic alignment module and a camera module to monitor to ensure that the two lasers are coaxially incident on the workpiece and the stability of beam combination during the processing. The specific method is: Turn on the ultrafast laser, adjust the polarization state of the ultrafast laser so that it completely passes through the polarization beam splitter, and adjust the position of the camera monitoring module so that the beam is at the center of the screen; Use the FPGA control module to collect and process the camera image, extract the center point of the beam by combining the fast extraction algorithm for the center of the Gaussian distribution spot, record the corresponding pixel point coordinates at present and turn off the ultrafast laser; Turn on the long / short pulse laser, adjust the polarization state of the long / short pulse laser so that it is reflected after passing through the polarization beam splitter, and use the precise adjustment module of the electric mirror to adjust the laser beam direction so that it is also incident on the camera monitoring module and is also at the center of the screen; Process the camera image, extract the beam center point of the long / short pulse laser, and compare the difference in the pixel coordinates of the centers of the two laser beams; Feedback and adjust the electric mirror to adjust the beam direction of the long / short pulse laser to ensure that the centers of the two spots completely coincide, and always monitor their alignment during the output process.

[0047] The number of ultrafast laser pulses in the super-pulse laser is 1 to 100,000.

[0048] As Figure 3As shown, the initial repetition frequency, pulse energy, pulse width, and number of pulses of the ultrafast laser and the long / short pulse laser are controlled by analog / digital signals. The specific method is as follows: By adjusting the voltage value of the analog signal, the control of the output pulse energy of the ultrafast laser and the long / short pulse laser can be achieved. The analog signal voltage corresponds one-to-one with the laser pulse energy output ratio; By adjusting the repetition frequency of the digital signal, the control of the output repetition frequency of the ultrafast laser and the long / short pulse laser can be achieved. The frequency of the digital signal corresponds one-to-one with the laser output frequency.

[0049] Such as Figure 4 、 5 As shown, the output synchronization signal is used to accurately control the timing delay and pulse action time between the two lasers. The specific method is as follows: Set the timing delay and pulse action time between the two lasers; Such as Figure 4 In the synchronization signal 1, it is used to control the output of the ultrafast laser pulses. By setting the number of pulses, pulse width, and repetition frequency of the touch synchronization signal, calculating its pulse action time, and setting the starting time to 0; According to the initial timing delay, such as Figure 4 Shown in the synchronization signal 2, set the pulse starting time of the synchronization signal for triggering the output of the long / short pulse laser, output the synchronization signal, and finally the pulses of the two different lasers are combined into a super pulse, such as Figure 4 Shown in the corresponding image of the super pulse output in

[0050] Combined with a high-speed photodetector to detect the timing relationship and pulse action time between the laser pulses inside the super pulse and between the super pulses. The specific method is as follows: Turn on the super pulse laser and adjust the position of the high-speed photodetector to detect the corresponding signal; Use FPGA to control the acquisition of the high-speed photodetector signal, combine signal processing methods to extract the waveform of the photoelectric signal, and calculate parameters such as the starting position, ending position, and pulse width of the corresponding signal; According to the starting position of the first pulse of the ultrafast laser inside the super pulse and the starting position of the long / short pulse laser pulse, calculate the pulse delay between the two, and calculate the relative position of the two laser pulses according to their pulse action time, thereby determining the timing relationship between the laser pulses inside the super pulse and between the super pulses.

[0051] Figure 6 Shows the super pulse waveform monitored by the high-speed photodetector and its detectable parameters.

[0052] Example 4 This embodiment is about the output waveform 1 of an ultra-pulsed laser system and its application in the processing of non-light-transmitting materials. For the processing of metal materials or ceramic materials, it is often necessary to balance processing quality and processing efficiency. Traditional long / short pulsed laser processing cannot achieve high-quality processing, while ultrafast lasers cannot balance processing efficiency. Taking the example of machining holes or cutting on stainless steel, an ultra-pulsed laser output method of the present invention mainly includes the following steps: Step 1, turn on the ultra-pulsed laser output system; Step 2, use a variable magnification beam expander to adjust the beam diameters of the ultrafast laser and the long / short pulsed laser, so that the beam diameter of the ultrafast laser is larger than that of the long / short pulsed laser; Step 3, use a beam combining module to combine the ultrafast laser and the long / short pulsed laser, and combine a beam automatic alignment module and a camera module to monitor to ensure that the two lasers maintain coaxial output and the stability of the beam output; Step 4, set the initial repetition frequency of the ultrafast laser to 10 kHz (20 internal 1 GHz pulse trains), the pulse energy to 100 uJ, the pulse width to 300 fs, the number of pulses to 4, the initial repetition frequency of the long / short pulsed laser to 1 kHz, the pulse width to 200 ns, the number of pulses to 1, and the pulse energy to 1 mJ; The time delay between the two lasers is set to 185 ns, the starting trigger time of the ultrafast laser is 185 ns, and the starting trigger setting of the long / short pulsed laser is set to 0; The time delay between two adjacent ultra-pulsed lasers is set to 1 ms; Step 5, use the FPGA control module to output corresponding analog signal voltages to control the pulse energies of the ultrafast laser and the long / short pulsed laser respectively, output corresponding digital signals to control the repetition frequencies of the ultrafast laser and the long / short pulsed laser respectively. In addition, according to the set time delay, output corresponding synchronization signals to form ultra-pulses, and combine a high-speed photodetector to detect the time sequence relationship and pulse action time between the internal laser pulses of the ultra-pulses and between the ultra-pulses, so as to realize the output of ultra-pulsed lasers. The output ultra-pulses are as Figure 9 shown; Step 6, use the "hot melting" effect of the long / short pulsed laser to achieve high-efficiency removal. At the same time, combined with the "cold" processing characteristics of the ultrafast laser, before the hot melting area formed by the previous long / short pulsed laser has not solidified, use a sequence of ultrafast laser pulses to remove the hot melting area, so as to ensure high quality while achieving high-efficiency processing.

[0053] Example 5 This embodiment is about the output waveform 2 of the ultra-pulsed laser system and its application in the processing of light-transmitting materials For optically transparent materials such as glass and sapphire, directly processing with ultrafast lasers often results in cracks, and the absorption rate of optically transparent materials for long / short pulse laser processing is extremely low, making it impossible to achieve processing. Taking the example of machining holes or welding on silicon carbide, a method for outputting super-pulse lasers according to the present invention mainly includes the following steps: Step 1, turn on the super-pulse laser output system; Step 2, use a variable magnification beam expander to adjust the beam diameters of the ultrafast laser and the long / short pulse laser, so that the beam diameter of the ultrafast laser is smaller than that of the long / short pulse laser; Step 3, use a beam combining module to combine the ultrafast laser and the long / short pulse laser, and combine the beam automatic alignment module and the camera module to monitor to ensure that the two lasers maintain coaxial output and the stability of the beam output; Step 4, set the initial repetition frequency of the ultrafast laser to 50 Hz, the pulse energy to 100 uJ, the pulse width to 300 fs, the number of pulses to 1, the initial repetition frequency of the long / short pulse laser to 50 Hz, the pulse width to 10 ms, the number of pulses to 1, the pulse energy to 100 mJ, set the time sequence delay between the ultrafast laser and the long / short pulse laser to 4 ms, the starting trigger time of the ultrafast laser to 4 ms, the starting trigger setting of the long / short pulse laser to 0, and the time sequence delay between two adjacent super-pulse lasers to 1 ms; Step 5, use the FPGA control module to output corresponding analog signal voltages to control the pulse energies of the ultrafast laser and the long / short pulse laser respectively, output corresponding digital signals to control the repetition frequencies of the ultrafast laser and the long / short pulse laser respectively. In addition, according to the set time sequence delay, output corresponding synchronization signals to form super-pulses, and combine a high-speed photodetector to detect the time sequence relationship and pulse action time between the internal laser pulses of the super-pulses and between the super-pulses to achieve the output of super-pulse lasers. The output super-pulses are as Figure 10 shown; Step 6, use the ultrafast laser to achieve electron excitation in the internal region of the silicon carbide material to increase its light absorption rate for the long / short pulse laser, so as to quickly remove the silicon carbide material by using the thermal removal effect of the long / short pulse laser. At the same time, the hot melting effect generated by the long / short pulse laser on the hole wall will also finish machining the hole wall to achieve a high-quality hole wall surface, ensuring high quality while achieving high-efficiency processing.

[0054] Example 3 The output waveform 3 of the super-pulse laser system in this example and its application in material synthesis In traditional material synthesis, high-energy long / short laser pulses are often used to irradiate powders, and the melting effect is utilized to fuse different materials to form new materials. However, the density of the formed materials cannot be guaranteed. Ultrafast laser-induced shock waves can further compress the materials and improve their properties. Taking the synthesis of iron-based new materials as an example, it mainly includes the following steps: Step 1: Turn on the ultrafast laser output system; Step 2: Use a variable magnification beam expander to adjust the beam diameters of the ultrafast laser and the long / short pulse laser, making the beam diameter of the ultrafast laser smaller than that of the long / short pulse laser; Step 3: Use a beam combining module to combine the ultrafast laser and the long / short pulse laser, and combine the beam automatic alignment module and the camera module to monitor and ensure that the two lasers maintain coaxial output and the stability of the beam output; Step 4: Set the initial repetition frequency of the ultrafast laser to 50 Hz (20 in the internal 1 GHz pulse train), the pulse energy to 100 uJ, the pulse width to 300 fs, the number of pulses to 1, the initial repetition frequency of the long / short pulse laser to 50 Hz, the pulse width to 10 ms, the number of pulses to 1, the pulse energy to 100 mJ. Set the time delay between the two lasers to 4 ms, the starting trigger time of the ultrafast laser to 4 ms, and the starting trigger setting of the long / short pulse laser to 0; Set the time delay between two adjacent ultrafast laser pulses to 1 ms; Step 5: Use the FPGA control module to output corresponding analog signal voltages to control the pulse energies of the ultrafast laser and the long / short pulse laser respectively, output corresponding digital signals to control the repetition frequencies of the ultrafast laser and the long / short pulse laser respectively. In addition, according to the set time delay, output corresponding synchronization signals to form an ultrapulse, and combine a high-speed photodetector to detect the time sequence relationship and pulse action time between the internal laser pulses of the ultrapulse and between the ultrapulses, so as to realize the output of the ultrapulse laser. The output ultrapulse is as Figure 11 shown; Step 6: Use the long / short pulse laser to irradiate the uniformly mixed powder, and use its melting effect to fuse the powder. When the thermal effect still remains in the matrix, use the high-pressure effect generated by the ultrafast laser-induced strong shock wave on the matrix to form a high-performance new material.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. An ultra-pulse laser output system, characterized in that: It includes an FPGA control module, an ultrafast laser source, a long / short pulse laser source, a beam combining module, a first electric variable magnification beam expander and a second electric variable magnification beam expander, wherein: The long / short pulse laser source is incident on the beam combining module through a second electric variable magnification beam expander; The ultrafast laser source is incident on the beam combining module through a first electric variable magnification beam expander; The ultra-pulse laser output by the beam combining module is focused onto the surface of the workpiece; The FPGA control module is respectively controlled and connected with the ultrafast laser source, the long / short pulse laser source, the first electric variable magnification beam expander and the second electric variable magnification beam expander.

2. The ultra-pulse laser output system according to claim 1, characterized in that: The long / short pulse laser source is incident on the second electric variable power beam expander through a reflector; a beam auto-collimation module is arranged between the second electric variable power beam expander and the beam combining module, and the beam auto-collimation module is control-connected to the FPGA control module.

3. The ultra-pulse laser output system according to claim 2, characterized in that: The beam self-collimation module comprises a first electric reflector and a second electric reflector, wherein the first electric reflector and the second electric reflector are arranged in mirror symmetry.

4. An ultra-pulse laser output system according to any one of claims 1 to 3, characterized in that: A part of the ultra-pulse laser output by the beam combining module is incident on a real-time monitoring module for obtaining a beam alignment deviation value between two beam expansion lasers in the ultra-pulse laser, and the real-time monitoring module is control-connected to the FPGA control module.

5. The ultra-pulse laser output system according to claim 4, characterized in that: The real-time monitoring module includes a beam splitter, a high-speed photodetector and a camera module, wherein the ultra-pulse laser output by the beam combining module is incident on the beam splitter, one of the two ultra-pulse lasers output by the beam splitter is incident on the high-speed photodetector, and the other ultra-pulse laser is incident on the camera module.

6. The ultra-pulse laser output system according to claim 1, characterized in that: The beam combining module includes two λ / 2 wave plates and a polarization beam splitter, wherein the two λ / 2 wave plates are vertically placed at 90° with the polarization beam splitter as the center, the light beam output by the light beam self-collimation module is incident on one of the λ / 2 wave plates, the light beam of the first electric reflector is incident on the other λ / 2 wave plate, and the light beams output by the two λ / 2 wave plates are both incident on the polarization beam splitter.

7. The ultra-pulse laser output system according to claim 1, characterized in that: The FPGA control module includes a signal and image acquisition subunit, a signal and image processing subunit, a signal input / output control subunit and a device control subunit, wherein: The input end of the signal and image acquisition subunit is connected to the output end of the real-time monitoring module to collect photoelectric signals and image data; The signal and image processing subunit is used to extract the light beam delay deviation value and the light beam alignment deviation value from the received photoelectric signal and image data respectively; The signal input / output control subunit is used to control the timing relationship between the ultrafast laser and the long / short pulse laser, and control the parameters of the ultrafast laser source and the long / short pulse laser source; The device control subunit is respectively connected to the beam autocollimation module, the first electric variable-power beam expander and the second electric variable-power beam expander to control the beam diameter and the coaxiality of the two laser beams.

8. The ultra-pulse laser output system according to claim 1, characterized in that: The ultrafast pulse source is a laser with a pulse width of 0fs-10ps, and the long / short pulse laser is a laser with a pulse width between 0ns and 100ms.

9. A super pulse laser output method, characterized in that: An ultra-pulse laser output system according to any one of claims 1 to 8, comprising the following steps: Setting the timing delay between two adjacent super pulse lasers; Setting the initial repetition frequency, pulse energy, pulse width and number of pulses corresponding to the ultrafast laser source and the long / short pulse laser source within each ultra-pulse laser duration; Setting the timing delay between the ultrafast laser source and the long / short pulse laser source within each ultra-pulse laser duration; respectively setting the start triggering time of the ultrafast laser source and the long / short pulse laser source within each ultra-pulse laser duration; Turn on the ultrafast laser light source and the long / short pulse laser light source; The beam diameters of the emitted ultrafast laser and the long / short pulse laser are respectively expanded by variable magnification to obtain two beams of expanded lasers; The two expanded laser beams are combined to obtain a super pulse laser, which is focused onto the surface of the workpiece.

10. The ultra-pulse laser output method according to claim 9, characterized in that: The method also includes: acquiring in real time a beam alignment deviation value between two beam expansion lasers in the ultra-pulse laser, and adjusting the coaxiality between the ultrafast laser and the long / short pulse laser using the beam alignment deviation value.

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