A multi-channel picosecond laser and method of generation

Abstract

The application relates to the field of laser technology, in particular to a multi-channel picosecond laser and a generating method, which comprises a seed source laser, a pulse selection module, a power amplification module and an output module; the seed source laser is used for generating high-frequency picosecond seed pulses; the pulse selection module is used for selecting pulses with required frequency and quantity from the high-frequency seed pulses; the power amplification module is used for power amplifying the selected pulses; the output module is used for outputting the amplified laser pulses; the pulse selection module comprises a photoelectric detection unit, a pick pulse control board and an acousto-optic modulator; the photoelectric detection unit converts optical signals output by the seed source into electrical signals; the pick pulse control board receives the electrical signals; the acousto-optic modulator receives an acousto-optic driving signal driven by a square wave signal; the pulse selection module reduces the high-frequency seed pulses with MHz level to low-frequency pulses with kHz level, and then the low-frequency pulses are amplified by single-stage or multi-stage power amplification, so that the single-pulse energy and the peak power are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a multi-channel picosecond laser and its generation method. Background Technology

[0002] Existing picosecond lasers typically use an oscillating seed source to generate high-repetition-rate pulse sequences in the tens of megahertz range. The single-pulse energy of this seed pulse is only at the nanojoule level. If this high-frequency pulse is directly fed into the subsequent amplification link, the energy distribution during the amplification process will be dispersed due to the excessively dense number of pulses, making it difficult to increase the single-pulse energy to the microjoule or even millijoule level. At the same time, the high peak power density is also prone to inducing nonlinear effects in the amplification medium, further limiting the energy extraction efficiency. This means that when conventional picosecond lasers face precision processing scenarios that require high single-pulse energy, such as semiconductor wafer cutting and photovoltaic cell scribing, they often need to sacrifice the repetition frequency or add complex pre-amplification stages, but it is still difficult to achieve both high average power and sufficient single-pulse energy. Therefore, how to efficiently extract and control low-frequency high-energy pulses from a high-frequency seed source has become the core bottleneck restricting the improvement of picosecond laser processing capabilities.

[0003] Existing technologies attempt to use acousto-optic or electro-optic modulators to perform select-based frequency reduction processing on seed pulses. By reducing the repetition frequency, each amplified pulse can achieve higher gain. However, such solutions typically rely on simple frequency division triggering methods, and the timing accuracy and pulse number adjustment range of select-based control are limited. This makes it difficult to adapt to the flexible requirements of different processing technologies for pulse parameters. Furthermore, when multiple parallel outputs are required, the method of splitting the beam and then amplifying it separately is often used. This method has extremely high requirements for beam splitting uniformity and consistency of amplification of each path, which significantly increases system complexity and cost. Essentially, it still fails to solve the fundamental contradiction between effectively increasing single-pulse energy and output flexibility. Therefore, there is an urgent need for a picosecond laser and its generation method that can achieve comprehensive optimization in terms of select-based control accuracy, amplification efficiency, and output modes. Summary of the Invention

[0004] The purpose of this invention is to provide a multi-channel picosecond laser and a method for generating it, so as to solve the problems existing in the prior art.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A multi-channel picosecond laser includes a seed laser, a pulse selection module, a power amplification module, and an output module. The seed laser is used to generate high-frequency picosecond seed pulses; the pulse selection module is used to select pulses of a desired frequency and number from the high-frequency seed pulses; the power amplification module is used to amplify the selected pulses; and the output module is used to output the amplified laser pulses. The pulse selection module includes a photoelectric detection unit, a pulse picking control board, and an acousto-optic modulator; the photoelectric detection unit converts the optical signal output from the seed source into an electrical signal; the pulse picking control board receives the electrical signal; and the acousto-optic modulator receives an acousto-optic driving signal driven by a square wave signal.

[0006] By adopting the above technical solution, the pulse control board receives the electrical signal and outputs a square wave signal according to the preset frequency division parameters, delay parameters, and pulse quantity parameters; the acousto-optic modulator receives the acousto-optic driving signal driven by the square wave signal, extracts pulses of the corresponding frequency and quantity from the high-frequency seed pulse, and sends the first-order diffracted light to the power amplification module; the realization of picoseconds first requires a selection process. Typical seed sources are tens of megahertz, which are high frequencies. Direct amplification would result in excessively low single-pulse energy, preventing the laser from achieving a high single-pulse energy and peak power. The selection process involves choosing a seed from a fixed frequency of tens of megahertz. The selection system works by converting the light emitted from the seed source into an electrical signal via a photodiode (PD). This electrical signal is then sent to the selection board, specifically the currently used PPC-01A pulse selection board, which allows adjustment of frequency division, delay, and pulse count. A square wave signal is then output to the acousto-optic driver, which in turn outputs the corresponding radio frequency to the AOM (Audio-Optical Array). The AOM extracts a portion of the higher-frequency pulses, and the first-stage diffracted light output from the AOM is then sent to the amplification stage for amplification.

[0007] In a further embodiment, the pulse picking control board is a PPC-01A type pulse picking board.

[0008] By adopting the above technical solution, the PPC-01A type pulse picking board can realize frequency division adjustment, delay adjustment and pulse number adjustment, and can extract 1-2046 pulses from a high repetition rate seed laser of 1-100MHz according to a set window, thereby reducing the output repetition frequency.

[0009] In a further embodiment, the power amplification module includes a single-stage amplifier / multi-stage amplifier.

[0010] By adopting the above technical solution, the selected pulse is amplified to increase the energy of the nanojoule-level pulse to the microjoule level or higher.

[0011] In a further embodiment, the multi-channel picosecond laser further includes a first optical isolator disposed between the seed source laser and the pulse selection module, and a second optical isolator disposed between the pulse selection module and the power amplification module.

[0012] By adopting the above technical solution, the first optical isolator and the second optical isolator are used to prevent the reflected light from damaging the front-end devices. The output end of the power amplifier module is also equipped with a switching optical-acoustic-optic modulator to control the on / off state of the laser output.

[0013] In a further embodiment, the multi-channel picosecond laser also includes a beam splitting unit disposed between the pulse selection module and the power amplification module; The beam splitting unit consists of a beam splitter and an optical fiber beam splitter / diffraction beam splitting element.

[0014] By adopting the above technical solution, the beam splitting unit is used to divide the laser after pulse selection into multiple branch lasers. Each branch laser is amplified by its corresponding power amplification unit and then output by its corresponding output unit, thereby realizing multi-channel laser output.

[0015] This invention also discloses a method for generating a multi-channel picosecond laser, comprising the following steps: Step S1: Generate high-frequency picosecond seed pulses using a seed source laser; Step S2: The photoelectric detection unit converts the optical signal of the seed pulse into an electrical signal and sends the electrical signal to the picking pulse control board; Step S3: The pulse control board outputs a square wave signal to the acoustic-optical drive circuit according to the preset frequency division parameters, delay parameters, and pulse quantity parameters. Step S4: The acousto-optic driving circuit drives the acousto-optic modulator to extract pulses of the corresponding frequency and number from the high-frequency seed pulses and output first-order diffracted light. Step S5: Send the first-stage diffracted light to the power amplifier module for single-stage or multi-stage amplification; Step S6: Output the amplified laser pulse through the output unit.

[0016] In a further embodiment, step S4 may include: splitting the laser after pulse selection processing into multiple branch lasers through a beam splitting unit, and amplifying each branch laser by its corresponding power amplification unit before outputting.

[0017] By adopting the above technical solution,

[0018] In a further embodiment, the number of power amplification stages and the gain parameters are adjusted according to the required output single-pulse energy.

[0019] By adopting the above technical solution,

[0020] In a further embodiment, the method further includes: outputting a 0-5V level signal to the acousto-optic driver via the main control board to drive the acousto-optic shutter to change its closed state, thereby increasing or decreasing losses and controlling the output power.

[0021] In summary, the present invention has the following beneficial effects: 1. The high-frequency seed pulse at the MHz level is down-frequencyd to the low-frequency pulse at the kHz level by the pulse selection module, and then amplified by one or more stages to effectively improve the single pulse energy and peak power; the MHz high-frequency seed optical pulse is selected by the acousto-optic modulator to select the kHz laser pulse, and then amplified by one or more stages to achieve high single pulse energy output; the optical signal is converted into an electrical signal by the photoelectric detection unit and then processed by the pulse selection control board. The frequency and pulse number of the selection can be flexibly controlled by adjusting the frequency division parameter, delay parameter, and pulse number parameter to meet the pulse parameter requirements of different processing processes; the pulse selection control board can output a precise square wave signal to the acousto-optic driver, which drives the corresponding radio frequency signal to the AOM, and the AOM extracts the required pulse from the high-frequency pulse.

[0022] 2. By setting a beam splitting unit after the pulse selector, the laser light processed by the selector can be divided into multiple paths for amplification and output, realizing multi-channel parallel processing and significantly improving processing efficiency. The amplification parameters of each branch laser can be adjusted independently, offering high flexibility. The main control board outputs a 0-5V level signal to the acousto-optic driver, driving the acousto-optic shutter to change its closed state, enabling continuous adjustment of the output power. The power factor adjusts the PWM duty cycle / RF drive intensity; a higher value results in a longer diffraction time for the AOM (Aperture Oscillator) and higher laser energy; a lower value results in a shorter diffraction conduction time and lower output energy. Optical isolators are installed between the seed source and the pulse selector module, and between the pulse selector module and the power amplification module, effectively preventing damage to front-end devices from reflected light and improving system stability and lifespan. Attached Figure Description

[0023] Figure 1 This is a system structure block diagram of the multi-channel picosecond laser of the present invention; Figure 2 This is a schematic diagram illustrating the working principle of the pulse selection module of the present invention; Figure 3 This is a schematic diagram of the optical path of the multi-channel picosecond laser of the present invention; Figure 4 This is a schematic flowchart of the multi-channel picosecond laser generation method of the present invention; Figure 5 This is a schematic diagram illustrating the principle of signal change in the laser output controlled by an external control signal according to the present invention. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings.

[0025] It should be noted that in the description of this invention, any descriptions of orientation, such as up, down, front, back, left, right, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of this invention.

[0026] Example 1: like Figures 1-3 As shown, a multi-channel picosecond laser includes a seed laser, a pulse selection module, a power amplification module, and an output module. The seed laser uses a fiber mode-locked oscillator as the seed source to generate high-frequency picosecond seed pulses with a repetition frequency of tens of megahertz. The single-pulse energy of the seed pulse is on the nanojoule level, and the pulse width is on the picosecond level. The optical pulses output by the seed laser first enter the pulse selection module.

[0027] The pulse selection module consists of a photoelectric detection unit, a pulse selection control board, an acousto-optic drive circuit, and an acousto-optic modulator connected in sequence. The photoelectric detection unit specifically uses a high-speed photodiode, which converts the optical signal output from the seed source into a corresponding electrical signal. The frequency of this electrical signal matches the repetition frequency of the seed pulse. This electrical signal is then sent to the pulse selection control board, which is a PPC-01A type. This board has a built-in field-programmable gate array and digital signal processor, enabling real-time analysis and processing of the input electrical signal. Users can set frequency division parameters, delay parameters, and pulse quantity parameters to the pulse selection control board via host computer software according to the actual requirements of the processing technology. The pulse selection control board then identifies and extracts the required pulse from the continuous high-frequency electrical signal based on these preset parameters. A time window is established, during which a rectangular square wave signal is output to the acousto-optic drive circuit. Upon receiving the square wave signal, the acousto-optic drive circuit converts it into a radio frequency (RF) signal of corresponding frequency and power. This RF signal is applied to the transducer of the acousto-optic modulator, which converts it into an ultrasonic field of the same frequency. This ultrasonic field forms a periodic refractive index grating within the acousto-optic medium. When a seed pulse passes through this acousto-optic medium, the portion of the pulse light that satisfies the Bragg diffraction condition is diffracted to the first-order diffraction direction, while the remaining pulse light that does not meet the condition is transmitted along the zero-order direction and blocked and absorbed by subsequent apertures. Thus, the acousto-optic modulator precisely extracts the corresponding frequency and number of pulses from the high-frequency seed pulse, achieving single-pulse downsampling and reducing the high-frequency pulse sequence of tens of megahertz to a low-frequency pulse sequence in the kilohertz range, while maintaining the picosecond width of each pulse.

[0028] The first-order diffracted light output from the acousto-optic modulator enters the power amplifier module after passing through the first optical isolator. The first optical isolator consists of a polarization beam splitter and a Faraday rotator, allowing only the forward-propagating laser to pass through while blocking the backward-propagating return light to prevent it from entering the seed source laser and causing instability or even damage to the seed source. The power amplifier module includes a preamplifier and a main power amplifier. The preamplifier uses a ytterbium-doped fiber amplifier to initially amplify the nanojoule-level seed pulse to the microjoule level. The main power amplifier uses a rod crystal amplifier or a slab amplifier to further increase the pulse energy to the hundreds of microjoules or even millijoules level. The pump power and gain length of the amplifier are optimized according to the required output single pulse energy. After power amplification, the laser pulse passes through the second optical isolator and then enters the switchable optical-acoustic-optic modulator. The structure and function of the second optical isolator are the same as those of the first optical isolator. It is used to prevent the backlight generated at the back end of the power amplification module from being transmitted back to the preamplifier and causing damage to the gain medium. The switchable optical-acoustic-optic modulator is used to receive the 0 to 5 volt level signal output by the main control board. The amplitude of this level signal determines the diffraction efficiency of the acousto-optic shutter. When the level signal is high, the acousto-optic shutter is opened, and the amplified laser pulse enters the output module after passing through the switchable optical-acoustic-optic modulator.

[0029] The output module includes a beam expander and collimator lens group and a focusing lens, which are used to expand the beam diameter of the laser pulse and collimate it before focusing it onto the processing surface. When the level signal is low, the acousto-optic shutter is closed, and the laser pulse is blocked at the switching acousto-optic modulator and cannot be output, thereby realizing rapid control of laser output and shutdown. The main control board continuously changes the diffraction loss of the acousto-optic shutter by adjusting the amplitude of the output level signal. The larger the level signal amplitude, the greater the degree of opening of the acousto-optic shutter, the higher the diffraction efficiency, the less the transmission loss, and the higher the output energy. Conversely, the smaller the level signal amplitude, the lower the output energy, thereby realizing fine and continuous adjustment of the output power.

[0030] Example 2: like Figure 4 and Figure 5 As shown, the process includes steps S1 to S6 executed sequentially. Step S1 generates high-frequency picosecond seed pulses through a seed source laser. The seed source laser outputs a picosecond pulse sequence with a repetition frequency of tens of megahertz using a mode-locked oscillation method. This pulse sequence serves as the original light source for the entire laser system, and its pulse width and spectral width determine the basic characteristics of the final output laser. After the seed source laser is powered on, it undergoes a preheating and frequency stabilization process. Once the output power and repetition frequency are stable, the subsequent steps are performed.

[0031] Step S2 involves converting the optical signal of the seed pulse into an electrical signal using a photoelectric detection unit and transmitting the electrical signal to the pick pulse control board. The photoelectric detection unit uses a high-speed response photodiode, whose response time is less than one-tenth of the seed pulse width, to ensure accurate capture of the arrival time of each seed pulse. After the photodiode converts the optical pulse into a corresponding electrical pulse, the electrical pulse is amplified and shaped by a circuit to form a clean electrical signal, which is then input to the signal input terminal of the pick pulse control board.

[0032] Step S3 involves outputting a square wave signal to the audio-visual driving circuit based on the preset frequency division parameters, delay parameters, and pulse quantity parameters of the pulse picking control board. The pulse picking control board stores a user-preset parameter combination, which is issued as an instruction by the host computer software and stored in the control board's memory. After receiving the electrical signal, the pulse picking control board uses its rising or falling edge as a synchronization reference. According to the frequency division parameters, it selects one of every N input pulses as the gating reference. Then, according to the delay parameters, it delays the gating reference for a specific time to align with the pulse peak position. Finally, according to the pulse quantity parameters, it determines how many pulses corresponding to the square wave width are output within the gating window. The pulse picking control board ultimately synthesizes a rectangular square wave signal with precise timing relationship and outputs it to the audio-visual driving circuit.

[0033] In step S4, the acousto-optic driving circuit drives the acousto-optic modulator to extract pulses of the corresponding frequency and number from the high-frequency seed pulses and output first-order diffracted light. The acousto-optic driving circuit converts the square wave signal into a radio frequency power signal. The frequency of the radio frequency power signal is strictly matched with the operating frequency designed for the acousto-optic modulator. The radio frequency power signal is applied to the piezoelectric transducer of the acousto-optic modulator to excite an ultrasonic field in the acousto-optic medium. The ultrasonic field causes the refractive index of the medium to change periodically, forming a volume grating. When the seed pulse is incident on the grating region at a Bragg angle, Bragg diffraction occurs. Only the first-order diffracted light is guided to the subsequent optical path. The zero-order diffracted light and other higher-order diffracted light are intercepted by the aperture, thereby extracting discrete kHz pulse trains from the continuous MHz pulse train.

[0034] Step S5 delivers the first-stage diffracted light to the power amplifier module for single-stage or multi-stage amplification. The power amplifier module is configured as a single-stage amplifier structure or a multi-stage cascaded amplifier structure according to the required final output energy. Each amplifier stage includes a corresponding pump source, gain medium, and coupling optical path. The first-stage diffracted light first enters the first-stage amplifier through an isolator for pre-amplification. The pulse energy after pre-amplification is increased by more than an order of magnitude. Then, it is amplified by the second-stage amplifier. The pulse energy after main amplification is further increased to the microjoule level that meets the processing requirements. The pump power and gain fiber length of each amplification stage are coordinated and adjusted according to the target value of the final output single pulse energy. During the amplification process, synchronous pumping is used to ensure that the pump pulse and the signal pulse are precisely overlapped in time to maximize the energy extraction efficiency.

[0035] Step S6 outputs the amplified laser pulse through the output unit. The output unit receives the amplified laser pulse and performs beam shaping and focusing. Beam shaping includes using a beam expander to enlarge the beam diameter, using a collimator to convert the diverging light into parallel light, and using a waveplate to adjust the polarization state. Focusing uses a focusing lens to converge the parallel light to the processing focal point. Before step S6, the main control board outputs a 0 to 5 volt level signal to the acousto-optic driver to drive the acousto-optic shutter to change its closed state. The level signal is calculated in real time by the main control board based on the output power percentage set by the host computer. The higher the level signal, the higher the diffraction efficiency of the acousto-optic shutter and the more laser energy passes through. The lower the level signal, the lower the diffraction efficiency and the less laser energy passes through, thereby achieving closed-loop precise control of the final output power.

[0036] The system also includes a mode selection module, as shown in the table below: ; The POWER internal and external control, when this value equals INT, sets the output light power through this software, thereby changing the single pulse energy; EMISSION light, used to indicate whether current is output; INTERLOCK light: whether the TK pin of the INTERFACE port of the PMAIN-01A main control board is shorted with IG; KEYSWITCH light: whether the KS port of the PMAIN-01A main control board is shorted; ERROR light: whether there is an alarm; STATUS: current working status.

[0037] Freq represents the down-conversion frequency, i.e., the current laser output frequency; FreqDIV represents the down-conversion frequency, and the frequency after secondary frequency division; Fseed represents the seed source frequency; SeedPower represents the data read from PPC-01A, which is related to the strength of the synchronization signal; T3&T4 represents the temperature of ports T3 and T4; Hours represents the operating time, and only the time when the current is calculated; Fseed is the seed source frequency, Freq is the laser frequency, Freq = For example, if Fseed = 20MHz and Y is a frequency division value set to 40, then... .

[0038] Example 3: A beam splitting unit is added between the pulse selection module and the power amplification module. The beam splitting unit is located on the first-stage diffraction output optical path of the acousto-optic modulator, after the first optical isolator and before the power amplification module. The beam splitting unit adopts a beam splitter that splits the light into two. The beam splitter has a dielectric film with a specific splitting ratio deposited on the substrate surface, so that the incident first-stage diffraction light is split into a first branch laser and a second branch laser according to a preset ratio. The splitting ratio can be selected as 50:50, 70:30 or other arbitrary ratios according to actual processing needs. Each branch laser is transmitted along a different optical path direction. The first branch laser enters the first power amplification unit, and the second branch laser enters the second power amplification unit. The first power amplification unit and the second power amplification unit are configured independently and each includes a preamplifier, a main amplifier and corresponding pump source and temperature control system. The gain parameters of each power amplification unit can be set independently. The first power amplification unit amplifies the first branch laser in one or more stages according to the first gain parameter, and the second power amplification unit amplifies the second branch laser in one or more stages according to the second gain parameter. The first gain parameter and the second gain parameter can be the same or different, so that the first branch laser and the second branch laser output lasers with different single pulse energies after amplification. The output terminal of the first power amplification unit is connected to the first output unit, and the output terminal of the second power amplification unit is connected to the second output unit. The first output unit and the second output unit independently collimate and focus the beam, and output laser A and laser B to two different processing stations or two different processing areas of the same station, respectively. A first switching photoacoustic-optic modulator is set between the first power amplification unit and the first output unit, and a second switching photoacoustic-optic modulator is set between the second power amplification unit and the second output unit. The first and second switch-mode photoacoustic-optic modulators are independently controlled to turn on and off by different channel control signals from the main control board, allowing laser paths A and B to be independently controlled for output and shutdown without interference. The beam splitting unit can also be replaced with a fiber beam splitter or a diffraction beam splitter to support more branch outputs. When a fiber beam splitter is used, the incident laser is split into multiple fiber outputs, each connected to a corresponding power amplification unit. When a diffraction beam splitter is used, the incident laser is diffracted by a diffraction grating or spatial light modulator to generate multi-level diffracted light, each level of diffracted light entering a corresponding power amplification unit. After amplification in their respective power amplification units, each branch laser is output through an independent switch-mode photoacoustic-optic modulator and output unit, thus forming a multi-channel parallel output picosecond laser system. Apart from sharing the same seed source and the same pulse selection module, each channel is completely independent after the beam splitting unit. This structure ensures the synchronization of laser pulses in time for each channel and gives each channel the flexibility to independently adjust output power and pulse energy.

[0039] In scenarios requiring simultaneous processing at multiple workstations, there is no need to configure multiple lasers separately. Only one multi-channel picosecond laser is needed to complete multiple processing tasks at the same time, which greatly reduces equipment costs and space occupation. At the same time, the switching optical-acoustic-optic modulators of each channel receive independent level signals output from the main control board for independent power adjustment. The level signals use 0 to 5 volt analog voltages. The main control board outputs multiple voltage signals of different amplitudes simultaneously through a multi-channel digital-to-analog converter to control the acousto-optic diffraction efficiency of each channel, thereby achieving independent and precise adjustment of the output power of each channel.

[0040] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0041] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A multi-channel picosecond laser, characterized in that: The system includes a seed laser, a pulse selection module, a power amplification module, and an output module. The seed laser is used to generate high-frequency picosecond seed pulses; the pulse selection module is used to select pulses of the desired frequency and number from the high-frequency seed pulses; the power amplification module is used to amplify the selected pulses; and the output module is used to output the amplified laser pulses. The pulse selection module includes a photoelectric detection unit, a pulse picking control board, and an acousto-optic modulator; the photoelectric detection unit converts the optical signal output from the seed source into an electrical signal; the pulse picking control board receives the electrical signal; and the acousto-optic modulator receives an acousto-optic driving signal driven by a square wave signal.

2. The multi-channel picosecond laser according to claim 1, characterized in that: The pulse picking control board is a PPC-01A type pulse picking board.

3. The multi-channel picosecond laser according to claim 1, characterized in that: The power amplification module includes a single-stage amplifier / multi-stage amplifier.

4. The multi-channel picosecond laser according to claim 1, characterized in that: The multi-channel picosecond laser also includes a first optical isolator disposed between the seed source laser and the pulse selection module, and a second optical isolator disposed between the pulse selection module and the power amplification module.

5. The multi-channel picosecond laser according to claim 1, characterized in that: The multi-channel picosecond laser also includes a beam splitting unit, which is located between the pulse selection module and the power amplification module; The beam splitting unit consists of a beam splitter and an optical fiber beam splitter / diffraction beam splitting element.

6. A method for generating a multi-channel picosecond laser according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1: Generate high-frequency picosecond seed pulses using a seed source laser; Step S2: The photoelectric detection unit converts the optical signal of the seed pulse into an electrical signal and sends the electrical signal to the picking pulse control board; Step S3: The pulse control board outputs a square wave signal to the acoustic-optical drive circuit according to the preset frequency division parameters, delay parameters, and pulse quantity parameters. Step S4: The acousto-optic driving circuit drives the acousto-optic modulator to extract pulses of the corresponding frequency and number from the high-frequency seed pulses and output first-order diffracted light. Step S5: Send the first-stage diffracted light to the power amplifier module for single-stage or multi-stage amplification; Step S6: Output the amplified laser pulse through the output unit.

7. The method for generating a multi-channel picosecond laser according to claim 6, characterized in that: Step S4 includes: splitting the laser after pulse selection into multiple branch lasers through a beam splitting unit, and then amplifying each branch laser by its corresponding power amplification unit before outputting it.

8. The method for generating multi-channel picosecond lasers according to claim 6, characterized in that: The number of power amplification stages and the gain parameters are adjusted according to the required output single-pulse energy.

9. The method for generating a multi-channel picosecond laser according to claim 6, characterized in that, Also includes: The main control board outputs a 0-5V level signal to the acoustic-optical driver.

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