Steep edge ultrafast pulse string laser control device and use method

Abstract

The invention provides a steep edge ultrafast pulse train laser control device and a using method, and relates to the technical field of lasers, the steep edge ultrafast pulse train laser control device comprises an ultrafast seed source, a high-speed amplitude modulator, a pulse amplification module, a high-power amplitude modulation module and a signal driving module, the high-speed amplitude modulator is used for performing primary amplitude modulation on the laser pulse output by the ultrafast seed source and respectively generating a pre-pulse and a main pulse; the high-speed amplitude modulator is connected with the pulse amplification module; the pulse amplification module is connected with the high-power amplitude modulation module, the high-power amplitude modulation module is used for carrying out secondary amplitude modulation on the amplified pre-pulse and main pulse, and the pre-pulse is cut off, so that the high-power amplitude modulation module only outputs the main pulse; the signal driving module is electrically connected with the high-speed amplitude modulator and the high-power amplitude modulation module. According to the invention, the pulse flatness and the steep edge characteristic of the output ultrafast pulse string laser can be ensured.

Description

Technical Field

[0001] The invention relates to the field of laser technology, and in particular to a steep-edge ultrafast pulse train laser control device and a use method thereof. Background Art

[0002] In the fields of particle accelerators and the study of the interaction between light and matter, the amplified pulse train needs to have both a sharp edge (usually ≤1ns, including a complete micropulse) and a flat pulse top (amplitude fluctuation ≤5%). In the process of power amplification, the general long pulse train (ns-us level) will have a pulse front overshoot phenomenon due to the accumulation and consumption of the reversed particle number; in order to obtain a flat pulse, pulse pre-shaping, pulse pumping, back-end chopping and other technologies can be used to control the pulse shape.

[0003] The Chinese patent with publication number CN118472755A discloses a pulse fiber laser with adjustable repetition rate, including a control module, a seed source, an injection source, at least one amplification module, a first circulator and a second circulator; the control module is used to control the seed source to output a seed pulse with adjustable repetition rate, and control the injection source to output an injection pulse with adjustable repetition rate; the seed pulse output by the seed source is incident on the first end of the first circulator, and the injection pulse output by the injection source is incident on the first end of the second circulator; the seed pulse passes through the first end and the second end of the first circulator and then enters the amplification module for amplification, and then outputs after passing through the second end and the third end of the second circulator; the injection pulse passes through the first end and the second end of the second circulator and then is reversely injected into the amplification module, and the generated amplified spontaneous radiation is output from the third end of the first circulator. The pulse pre-shaping of the above scheme has limited correction ability for overshoot phenomenon, and it is difficult to meet the higher requirements for the flat characteristics of the pulse top; and the pulse pump is not suitable for high repetition rate pulses; the back-end chopper response bandwidth is low, and when the micro-pulse interval is less than 1ns, it is difficult to achieve the modulation requirements of the steep edge pulse train. Therefore, it is very necessary to provide a steep-edge ultrafast pulse train laser control device and a method for using the same to ensure the pulse flatness and edge steepness characteristics of the output pulse. Summary of the invention

[0004] In view of this, the present invention proposes a steep-edge ultrafast pulse train laser control device and a method of use. The laser pulse output by the ultrafast seed source is subjected to primary amplitude modulation by a high-speed amplitude modulator to generate a pulse train consisting of a pre-pulse and a main pulse. At the same time, the high-power amplitude modulation module performs secondary amplitude modulation on the amplified pulse, which can effectively cut off the distorted pre-pulse generated during the amplification process. Combining the characteristics of "high bandwidth and low withstand power" of the high-speed amplitude modulator and "low bandwidth and high withstand power" of the high-power amplitude modulator, the pulse flatness and steep edge characteristics of the output pulse are ensured.

[0005] In a first aspect, the present invention provides a steep-edge ultrafast pulse train laser control device, comprising an ultrafast seed source, a high-speed amplitude modulator, a pulse amplification module, a high-power amplitude modulation module, and a signal driving module, wherein:

[0006] The ultrafast seed source is connected to the high-speed amplitude modulator, and the high-speed amplitude modulator is used to perform primary amplitude modulation on the laser pulse output by the ultrafast seed source. There is a certain time interval between the pre-pulse and the main pulse, and the pre-pulse and the main pulse form a pulse train;

[0007] The high-speed amplitude modulator is connected to the pulse amplification module, and the pulse amplification module is used to amplify the pulse train;

[0008] The pulse amplification module is connected to the high-power amplitude modulation module, and the high-power amplitude modulation module is used to perform secondary amplitude modulation on the amplified pulse train and cut off the pre-pulse so that the high-power amplitude modulation module only outputs the main pulse;

[0009] The signal driving module is electrically connected to the high-speed amplitude modulator and the high-power amplitude modulation module respectively, and is used to provide a radio frequency driving signal to control the delay amount of the chopping signal of the high-speed amplitude modulator and the high-power amplitude modulation module respectively.

[0010] On the basis of the above technical solution, preferably, the high-power amplitude modulation module includes a half-wave plate, a Pockels cell and a polarization beam splitter, the half-wave plate is connected to the Pockels cell, and the Pockels cell is respectively connected to the signal driving module and the polarization beam splitter.

[0011] On the basis of the above technical solution, preferably, the signal driving module includes a first RF driver, a second RF driver and a clock source, the first RF driver is electrically connected to the clock source and the high-speed amplitude modulator, respectively, and the second RF driver is electrically connected to the clock source and the Pockels cell, respectively.

[0012] More preferably, the first RF driver receives a clock signal sent by the clock source and controls the shaping of the input laser pulse into a pre-pulse and a main pulse based on the clock signal, and the second RF driver is used to control the polarization rotation of the Pockels cell to remove the overshoot characteristics of the pre-pulse during the amplitude modulation process.

[0013] More preferably, when the phase difference bias of the high-speed amplitude modulator is at a phase of π, the output mode of the high-speed amplitude modulator is specifically as follows:

[0014] When no radio frequency pulse signal is input to the high-speed amplitude modulator, the high-speed amplitude modulator outputs a minimum continuous power;

[0015] When a radio frequency pulse signal is input to the high-speed amplitude modulator, the high-speed amplitude modulator outputs a corresponding optical pulse signal according to the pulse width and amplitude of the radio frequency pulse signal.

[0016] More preferably, when the phase difference bias of the high-speed amplitude modulator is at 0 phase, the output mode of the high-speed amplitude modulator is specifically:

[0017] When no radio frequency signal is input to the high-speed amplitude modulator, the high-speed amplitude modulation output continuous power is at a maximum value;

[0018] When a radio frequency pulse signal is input to the high-speed amplitude modulator, the high-speed amplitude modulator cuts off a corresponding waveform on the laser pulse output by the ultrafast seed source according to the pulse width and amplitude of the radio frequency pulse signal.

[0019] More preferably, the high-speed amplitude modulator is a high-bandwidth lithium niobate waveguide modulator or a lithium niobate thin film modulator, and the Pockels cell is a spatial electro-optic modulator.

[0020] More preferably, the pre-pulse width, the time interval between the pre-pulse and the main pulse, and the amplitude ratio between the pre-pulse and the main pulse can all be controlled by the RF driving signal output by the first RF driver.

[0021] More preferably, the repetition frequency of the ultrafast seed source does not exceed 2 GHz, the micropulse width does not exceed 100 ps, ​​and the interval between adjacent micropulses is not shorter than 400 ps.

[0022] In a second aspect, the present invention provides a method for using a steep edge ultrafast pulse train laser control device, comprising the following steps:

[0023] The laser pulse output by the ultrafast seed source is shaped into a pulse train consisting of a pre-pulse and a main pulse by a high-speed amplitude modulator driven by a first radio frequency drive signal, wherein the first radio frequency drive signal is generated by a signal drive module;

[0024] The pulse string is input into a pulse amplification module for amplification, and the amplified pulse string is input into the high-power amplitude modulation module driven by a second RF drive signal to perform secondary amplitude modulation on the amplified pulse string, and the pre-pulse is chopped off so that the high-power amplitude modulation module only outputs the main pulse, wherein the second RF drive signal is generated by a signal drive module.

[0025] The steep-edge ultrafast pulse train laser control device and use method provided by the present invention have the following beneficial effects compared with the prior art:

[0026] (1) The high-speed amplitude modulator performs primary amplitude modulation on the laser pulse output by the ultrafast seed source, which can accurately generate pre-pulses and main pulses, ensure the steep edge of the pulses, and meet the requirements of high-precision applications. The pulse amplification module amplifies the pre-pulses and main pulses, significantly improving the energy of the laser pulses. At the same time, the high-power amplitude modulation module performs secondary amplitude modulation on the amplified pulses, which can remove the pre-pulses that overshoot after amplification, and based on the sufficient time interval between the pre-pulses and the main pulses, the main pulses maintain good steep edge characteristics. The RF drive signal provided by the signal drive module can accurately control the waveform and timing of the output pulses of the high-speed amplitude modulator and the high-power amplitude modulation module, thereby ensuring the pulse flatness and steep edge characteristics of the output pulses.

[0027] (2) The waveform and timing of the output pulses of the high-speed amplitude modulator and the high-power amplitude modulation module are controlled by the first and second RF drivers respectively to achieve precise pulse synchronization. The first RF driver shapes the laser pulse into a pre-pulse and a main pulse according to the clock signal to ensure the stability of the shape before and after the pulse. The second RF driver adjusts the electric field of the Pockels cell to effectively remove the overshoot characteristics of the pre-pulse and reduce signal distortion. Through precise RF drive signal control, the stability and response speed of the amplitude modulation process are enhanced, thereby improving the overall modulation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the structure of a steep-edge ultrafast pulse train laser control device provided by the present invention;

[0030] Figure 2 A schematic diagram of the pulse waveform modulation process provided by the present invention.

[0031] Explanation of the reference numerals: 1. Ultrafast seed source; 2. High-speed amplitude modulator; 3. Pulse amplification module; 4. High-power amplitude modulation module; 41. Half-wave plate; 42. Pockels cell; 43. Polarization beam splitter; 5. Signal driving module. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, the present invention provides a steep edge ultrafast pulse train laser control device and a user, including an ultrafast seed source 1, a high-speed amplitude modulator 2, a pulse amplification module 3, a high-power amplitude modulation module 4 and a signal driving module 5, wherein:

[0034] The ultrafast seed source 1 is connected to a high-speed amplitude modulator 2, which is used to perform a first-level amplitude modulation on the laser pulse output by the ultrafast seed source 1 to generate a pulse train consisting of a pre-pulse and a main pulse. The high-speed amplitude modulator 2 is a high-bandwidth lithium niobate waveguide modulator.

[0035] The repetition frequency of the output pulse of the ultrafast seed source 1 does not exceed 2 GHz, the micropulse width does not exceed 100 ps, ​​and the interval between adjacent micropulses is not shorter than 400 ps. The ultrafast seed source 1 is a high repetition rate picosecond mode-locked pulse laser. The repetition frequency of the high repetition rate picosecond mode-locked pulse laser is 1 GHz, the micropulse width of the high repetition rate picosecond mode-locked pulse laser is 15 ps, and the interval between adjacent pulses of the high repetition rate picosecond mode-locked pulse laser is about 1 ns.

[0036] There are two chopping modes of the high-speed amplitude modulator 2. When the phase difference bias of the high-speed amplitude modulator 2 is at the π phase, the output mode of the high-speed amplitude modulator 2 is specifically as follows: when there is no RF pulse signal input to the high-speed amplitude modulator 2, the high-speed amplitude modulator 2 outputs a minimum continuous power; when an RF pulse signal is input to the high-speed amplitude modulator 2, the high-speed amplitude modulator 2 outputs a corresponding optical pulse signal according to the pulse width and amplitude of the RF pulse signal.

[0037] When the phase difference bias of the high-speed amplitude modulator 2 is at 0 phase, the output mode of the high-speed amplitude modulator 2 is specifically as follows: when there is no RF signal input to the high-speed amplitude modulator 2, the high-speed amplitude modulation output continuous power is at the maximum value; when an RF pulse signal is input to the high-speed amplitude modulator 2, the high-speed amplitude modulator 2 cuts off the corresponding waveform on the laser pulse output by the ultrafast seed source 1 according to the pulse width and amplitude of the RF pulse signal.

[0038] In this embodiment, when the phase bias is set to π phase, the output power of the modulator is the minimum when there is no RF pulse signal input, which is suitable for applications with higher requirements for pulse signal-to-noise ratio. After the RF pulse signal is input, the corresponding optical pulse signal can be output according to the pulse width and amplitude to achieve precise modulation. Under 0 phase bias, the output power of the modulator is the maximum when there is no RF signal input, which is suitable for applications with higher requirements for pulse top flatness. After the RF pulse signal is input, the corresponding waveform can be cut off from the laser pulse to accurately control the laser output. This flexible modulation method enhances the adaptability of the pulse laser control device and meets the requirements for laser pulse characteristics in different scenarios.

[0039] The high-speed amplitude modulator 2 is connected to a pulse amplification module 3, and the pulse amplification module 3 is used to amplify the pulse train. The pulse amplification module 3 can be an optical fiber, solid or optical-solid hybrid amplification system.

[0040] The pulse amplification module 3 is connected to the high-power amplitude modulation module 4, which is used to perform secondary amplitude modulation on the amplified pre-pulse and main pulse, and cut off the pre-pulse so that the high-power amplitude modulation module 4 only outputs the main pulse.

[0041] Further, the high-power amplitude modulation module 4 includes a half-wave plate 41, a Pockels cell 42 and a polarization beam splitter 43. The half-wave plate 41 is connected to the Pockels cell 42, and the Pockels cell 42 is respectively connected to the signal driving module 5 and the polarization beam splitter 43. The Pockels cell 42 is a lithium niobate (LN) or barium borate (BBO) spatial electro-optic modulator.

[0042] In this embodiment, by connecting the pulse amplification module 3 with the high-power amplitude modulation module 4, the high-power amplitude modulation module 4 includes a half-wave plate 41, a Pockels cell 42 and a polarization beam splitter 43, and the Pockels cell 42 is connected to the signal driving module 5 and the polarization beam splitter 43 as a spatial electro-optical modulator. The high-power amplitude modulation module 4 performs secondary amplitude modulation on the amplified pre-pulse and the main pulse, effectively separating the main pulse from the pre-pulse, ensuring that only the main pulse is output without affecting the leading and trailing edges of the main pulse, thereby improving the stability and accuracy of the pulse output and enhancing the performance of the pulse laser control device in high-power and high-precision pulse control.

[0043] The signal driving module 5 is electrically connected to the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4, respectively. The signal driving module 5 is used to provide a radio frequency driving signal to control the waveform and timing of the output pulses of the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4, respectively. The signal driving module 5 includes a first radio frequency driver, a second radio frequency driver and a clock source, the first radio frequency driver is electrically connected to the clock source and the high-speed amplitude modulator 2, respectively, and the second radio frequency driver is electrically connected to the clock source and the Pockels cell 42, respectively.

[0044] The first RF driver receives a clock signal sent by a clock source and shapes the input laser pulse into a pre-pulse and a main pulse based on the clock signal control. The second RF driver is used to control the electric field of the Pockels cell 42 to remove the overshoot characteristics of the pre-pulse during the amplitude modulation process. The timing of the drive signals output by the first RF driver and the second RF driver can be adjusted.

[0045] In this embodiment, the time delay of the output pulses of the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4 is controlled by the first and second RF drivers respectively to achieve precise pulse synchronization. The first RF driver shapes the laser pulse into a pre-pulse and a main pulse according to the clock signal to ensure the stability of the shape before and after the pulse. The second RF driver regulates the electric field of the Pockels cell 42 to effectively remove the overshoot characteristics of the pre-pulse and reduce signal distortion. Through precise RF drive signal control, the stability and response speed of the amplitude modulation process are enhanced, and the overall modulation accuracy is improved. The optimized pulse control and shape adjustment improve the working efficiency and consistency of the entire pulse laser control device, thereby ensuring the stable operation of the pulse laser control device under high power and high speed modulation conditions.

[0046] Furthermore, the width of the pre-pulse and the main pulse, the interval between the pre-pulse and the main pulse, and the amplitude ratio of the pre-pulse and the main pulse can all be controlled by the RF driving signals output by the first RF driver and the second RF driver.

[0047] The present invention performs primary amplitude modulation on the laser pulse output by the ultrafast seed source 1 through the high-speed amplitude modulator 2, and can accurately generate pre-pulses and main pulses, ensure that the edge of the pulse is steep, and meet the high-precision application requirements. The pulse amplification module 3 amplifies the pulse train, which significantly improves the energy of the laser pulse. The high-power amplitude modulation module 4 performs secondary amplitude modulation on the amplified pulse, which can remove the pre-pulse and ensure that the high-power amplitude modulation module 4 only outputs the main pulse, reducing unnecessary overshoot signal interference. The radio frequency driving signal provided by the signal driving module 5 can accurately control the output pulse delay of the high-speed amplitude modulator 2 and the high-power amplitude modulation module 4, thereby ensuring the pulse flatness and edge steepness characteristics of the output pulse.

[0048] In one example, if Figure 2 As shown in (a), the pulse train amplification generation method of the present invention has the following steps:

[0049] A1: The seed source uses a high-repetition-rate picosecond mode-locked pulse laser with a repetition rate of 1 GHz, a micro-pulse width of 15 ps, and an interval between adjacent pulses of about 1 ns.

[0050] A2: The picosecond seed source first passes through a high-speed amplitude modulation chopper, using a 20GHz bandwidth lithium niobate electro-optical modulator as a chopper device. The rising and falling edges can be in the order of hundreds of ps, and the pulse period is less than 1ns, which does not affect the integrity of the micropulse. After chopping, the pre-pulse width is about 10μs, including 10,000 micropulse periods (the pre-pulse width can be adjusted according to the actual amplification system, and the number of pulses is simplified in the diagram). The pre-pulse interval is 20ns (20 micropulse periods) before the main pulse, and the main pulse width is about 100μs, including 100,000 micropulse periods; the pulse train frequency after chopping is 1kHz;

[0051] A3: After the pulse train after the first-stage chopping passes through the first-stage fiber amplifier (gain is about 10dB), the front edge of the pre-pulse overshoots;

[0052] A4: The amplified laser passes through a spatial BBO Pockels cell 42 and a polarization beam splitter 43 (PBS) for chopping, removing the overshoot pre-pulse part and outputting the main pulse part with a flat top; the rising edge of the Pockels cell 42 is about 10ns, located in the timing gap between the pre-pulse and the main pulse, and will not destroy the steep edge characteristics of the main pulse. Finally, the pulse train laser output with sub-ps rising and falling edges, 1GHz micro-pulse repetition rate, 1kHz macro-pulse repetition rate, 100μs macro-pulse width, and amplitude fluctuation within the macro-pulse of no more than 5% is achieved.

[0053] In contrast, conventional pulse train amplification generation methods such as Figure 2 As shown in (b) in the figure, the steps are as follows:

[0054] B1: The seed source uses a high-repetition-rate picosecond mode-locked pulse laser with a repetition rate of 1 GHz, a micro-pulse width of 15 ps, and an interval between adjacent pulses of about 1 ns;

[0055] B2: The picosecond seed source is first chopped by a high-speed amplitude modulation, and the pulse train formed by the chopping is continuous without intervals; in some scenarios, step B2 can be omitted and amplified directly to generate continuous output micro pulses;

[0056] B3: After the pulse train after the first stage of chopping passes through the first stage of amplifier, the leading edge of the pre-pulse overshoots;

[0057] B4: In order to obtain a flat pulse leading edge, the overshoot part is cut off by a high-power amplitude modulator. However, due to the limited bandwidth of the high-power amplitude modulator and the long rising edge time, the micro-pulse amplitude at the edge of the pulse train will be incomplete. This problem is also faced in the above-mentioned application scenario of directly amplifying by skipping the B2 process.

[0058] By comparison, it can be seen that the device and method of the present invention can effectively produce a pulse train with a flat top and steep edges compared to the conventional pulse train amplification and generation method.

[0059] In a second aspect, the present invention provides a method for using a steep edge ultrafast pulse train laser control device, comprising the following steps:

[0060] Step S1, the laser pulse output by the ultrafast seed source 1 is shaped into a pre-pulse and a main pulse by a high-speed amplitude modulator 2 driven by a first radio frequency drive signal, wherein the first radio frequency drive signal is generated by a signal drive module 5;

[0061] Step S2, input the pre-pulse and the main pulse into the pulse amplification module 3 for amplification, and input the amplified pre-pulse and the main pulse into the high-power amplitude modulation module 4 driven by the second RF drive signal to perform secondary amplitude modulation on the amplified pre-pulse and the main pulse, and separate the main pulse from the pre-pulse so that the high-power amplitude modulation module 4 only outputs the main pulse, wherein the second RF drive signal is generated by the signal drive module 5.

[0062] In this embodiment, the laser pulse is shaped into a pre-pulse and a main pulse by a high-speed amplitude modulator 2 to ensure that the shape and edge of the laser pulse are steep. At the same time, the pre-pulse and the main pulse are input into the pulse amplification module 3 for amplification, which improves the energy of the laser pulse. The amplified pulse is subjected to secondary amplitude modulation by a high-power amplitude modulation module 4 to effectively separate the main pulse from the pre-pulse, ensuring that the high-power amplitude modulation module 4 only outputs the main pulse, avoiding unnecessary signal interference. The RF drive signal generated by the signal drive module 5 ensures the synchronization and stability of the entire process, and reduces the fluctuation and uncertainty in the pulse output process. By precisely controlling the shaping and amplification of the pulse, the main pulse finally output has better time characteristics and energy distribution, which is suitable for high-demand laser processing and measurement applications.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A steep edge ultrafast pulse train laser control device, characterized in that: It comprises an ultrafast seed source (1), a high-speed amplitude modulator (2), a pulse amplification module (3), a high-power amplitude modulation module (4) and a signal driving module (5), wherein: The ultrafast seed source (1) is connected to the high-speed amplitude modulator (2), and the high-speed amplitude modulator (2) is used to perform a first-level amplitude modulation on the laser pulse output by the ultrafast seed source (1), and respectively generate a pre-pulse and a main pulse, wherein there is a certain time interval between the pre-pulse and the main pulse, and the pre-pulse and the main pulse form a pulse train; The high-speed amplitude modulator (2) is connected to the pulse amplification module (3), and the pulse amplification module (3) is used to amplify the pulse train; The pulse amplification module (3) is connected to the high-power amplitude modulation module (4), and the high-power amplitude modulation module (4) is used to perform secondary amplitude modulation on the amplified pulse train and cut off the pre-pulse, so that the high-power amplitude modulation module (4) only outputs the main pulse; The signal driving module (5) is electrically connected to the high-speed amplitude modulator (2) and the high-power amplitude modulation module (4) respectively, and the signal driving module (5) is used to provide a radio frequency driving signal to control the delay amount of the chopping signal of the high-speed amplitude modulator (2) and the high-power amplitude modulation module (4) respectively.

2. The steep edge ultrafast pulse train laser control device according to claim 1, characterized in that: The high-power amplitude modulation module (4) comprises a half-wave plate (41), a Pockels cell (42) and a polarization beam splitter (43); the half-wave plate (41) is connected to the Pockels cell (42); and the Pockels cell (42) is respectively connected to the signal driving module (5) and the polarization beam splitter (43).

3. The steep edge ultrafast pulse train laser control device according to claim 2, characterized in that: The signal driving module (5) comprises a first RF driver, a second RF driver and a clock source, wherein the first RF driver is electrically connected to the clock source and the high-speed amplitude modulator (2) respectively, and the second RF driver is electrically connected to the clock source and the Pockels cell (42) respectively.

4. The steep edge ultrafast pulse train laser control device according to claim 3, characterized in that: The first RF driver receives a clock signal sent by the clock source and controls the shaping of the input laser pulse into a pre-pulse and a main pulse based on the clock signal. The second RF driver is used to control the polarization rotation of the Pockels cell (42) to remove the overshoot characteristics of the pre-pulse during the amplitude modulation process.

5. The steep edge ultrafast pulse train laser control device according to claim 1, characterized in that: When the phase difference bias of the high-speed amplitude modulator (2) is located at the π phase, the output mode of the high-speed amplitude modulator (2) is specifically as follows: When no radio frequency pulse signal is input to the high-speed amplitude modulator (2), the continuous power output by the high-speed amplitude modulator (2) is a minimum value; When a radio frequency pulse signal is input to the high-speed amplitude modulator (2), the high-speed amplitude modulator (2) outputs a corresponding optical pulse signal according to the pulse width and amplitude of the radio frequency pulse signal.

6. The steep edge ultrafast pulse train laser control device according to claim 5, characterized in that: When the phase difference bias of the high-speed amplitude modulator (2) is set to 0 phase, the output mode of the high-speed amplitude modulator (2) is specifically as follows: When no radio frequency signal is input to the high-speed amplitude modulator (2), the high-speed amplitude modulation output continuous power is at a maximum value; When a radio frequency pulse signal is input to the high-speed amplitude modulator (2), the high-speed amplitude modulator (2) cuts off a corresponding waveform on the laser pulse output by the ultrafast seed source (1) according to the pulse width and amplitude of the radio frequency pulse signal.

7. The steep edge ultrafast pulse train laser control device according to claim 2, characterized in that: The high-speed amplitude modulator (2) is a high-bandwidth lithium niobate waveguide modulator or a lithium niobate thin film modulator, and the Pockels cell (42) is a spatial electro-optical modulator.

8. The steep edge ultrafast pulse train laser control device according to claim 4, characterized in that: The pre-pulse width, the time interval between the pre-pulse and the main pulse, and the amplitude ratio between the pre-pulse and the main pulse can all be controlled by the RF driving signal output by the first RF driver.

9. The steep edge ultrafast pulse train laser control device according to claim 1, characterized in that: The repetition frequency of the pulse output by the ultrafast seed source (1) does not exceed 2 GHz, the width of the micro-pulse does not exceed 100 ps, ​​and the interval between adjacent micro-pulses is not shorter than 400 ps.

10. The method for using the steep edge ultrafast pulse train laser control device according to any one of claims 1 to 9, characterized in that: The steps include: The laser pulse output by the ultrafast seed source (1) is shaped into a pulse train consisting of a pre-pulse and a main pulse by a high-speed amplitude modulator (2) driven by a first radio frequency drive signal, wherein the first radio frequency drive signal is generated by a signal drive module (5); The pulse train is input into a pulse amplification module (3) for amplification, and the amplified pulse train is input into a high-power amplitude modulation module (4) driven by a second radio frequency drive signal to perform secondary amplitude modulation on the amplified pre-pulse and the main pulse, and the pre-pulse is cut off so that the high-power amplitude modulation module (4) only outputs the main pulse, wherein the second radio frequency drive signal is generated by a signal drive module (5).

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