A control method for ultrafast laser and laser main control board thereof

Abstract

The present application provides a control method for an ultrafast laser and its laser main control board, and relates to the field of laser technology. A timing reference is established through a mode-locked signal, and then the corresponding external trigger signal is pulse-width detected according to the mode-locked signal to obtain the corresponding number of Burst pulses, thereby realizing a dynamic adjustment method for the number of Burst pulses and improving the response speed. In addition, the frequency-selective light provided by the present application is selected from the laser pulse by the first acousto-optic modulator according to the corresponding number of Burst pulses, so that the repetition frequency of the laser pulse and the change of the number of Burst pulses are synchronized. In addition, the technical solution provided by the present application adjusts the gain balance mode of the amplifier according to the number of Burst pulses and the pulse interval of the external trigger signal. The gain balance mode makes the gain of the amplifier the same as the target gain, ensuring that the pulse energy remains stable under the condition of the current number of Burst pulses, and ultimately improving the performance of the ultrafast laser.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and more specifically, to a control method for an ultrafast laser and a laser main control board thereof. Background Art

[0002] Based on the different basic principles of ultrafast laser amplification processes, there are currently five main types of ultrafast lasers on the market, namely: disk type, slab type, fiber type, solid type and fiber-solid hybrid type (light-solid hybrid type means that the seed source uses fiber laser, and part of the amplifier uses solid-state amplification). The main structure of most existing ultrafast lasers is similar, generally consisting of a seed source, a pulse selector, an amplifier and an AOM (Acousto-optical Modulators). The structure of a femtosecond laser ultrafast laser will be slightly more complicated. It adds a stretcher between the seed source and the pulse selector, and adds a compressor after the amplifier. Nowadays, the application fields of ultrafast lasers are becoming more and more extensive, such as material processing, medical treatment, scientific research, high-end equipment and other fields. Therefore, high-performance ultrafast lasers have extremely high application value and broader application prospects. Summary of the invention

[0003] In view of this, the present application provides a control method for an ultrafast laser and a laser main control board thereof, which effectively solve the existing technical problems and improve the performance of the ultrafast laser.

[0004] To achieve the above objectives, the technical solutions provided by this application are as follows:

[0005] A method for controlling an ultrafast laser, comprising:

[0006] Acquire a mode-locking signal and a first external trigger signal, wherein the mode-locking signal is generated by a mode-locking oscillator according to laser pulse conversion of a repetition frequency, and the first external trigger signal is generated by a processing device according to a processing setting requirement;

[0007] Performing pulse width detection on the first external trigger signal according to the mode-locked signal to obtain the number of first Burst pulses, and determining the relationship between the pulse interval of the first external trigger signal and 1 / f0, where f0 is the reference frequency of the ultrafast laser;

[0008] If the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the number of the first Burst pulses, wherein the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than a target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light;

[0009] If the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the number of the first Burst pulses, and the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode equal to the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light;

[0010] If the pulse interval of the first external trigger signal is greater than 1 / f0, a first gain balance mode of the amplifier is determined according to the number of the first Burst pulses and a third control signal is generated, wherein the third control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, control the amplifier to operate in the first gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light, wherein the first gain balance mode makes the gain of the amplifier the same as the target gain.

[0011] Optionally, when the ultrafast laser switches the first number of Burst pulses to a second number of Burst pulses, the control method includes:

[0012] Determining that the ultrafast laser generates a switching control signal when switching the number of Burst pulses, wherein the switching control signal is used to control the second acousto-optic modulator to be turned off and to control the amplifier to maintain a current gain mode;

[0013] Acquire a gain switching signal, where the gain switching signal is generated by the processing equipment according to the number of the second Burst pulses;

[0014] Determine a second gain balance mode of the amplifier according to the gain switching signal and generate a gain control signal, wherein the gain control signal is used to control the amplifier to operate in the second gain balance mode, wherein the second gain balance mode makes the gain of the amplifier the same as the target gain;

[0015] After a set time, a second external trigger signal is obtained, where the second external trigger signal carries information about the number of the second Burst pulses;

[0016] The second external trigger signal is subjected to pulse width detection according to the mode-locked signal to obtain the second Burst pulse number, and a fourth control signal is generated according to the second Burst pulse number, wherein the fourth control signal is used to control the first acousto-optic modulator to obtain the frequency-selected light from the laser pulse, control the amplifier to operate in the second gain balance mode and amplify the frequency-selected light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light.

[0017] Optionally, determining that the ultrafast laser performs Burst pulse number switching includes:

[0018] When it is detected that the processing equipment stops outputting the first external trigger signal, it is determined that the ultrafast laser switches the number of Burst pulses.

[0019] Optionally, performing pulse width detection on a corresponding external trigger signal according to the mode-locked signal to obtain the number of Burst pulses includes:

[0020] Multiplying the mode-locked signal to a high clock reference signal;

[0021] The external trigger signal is processed by utilizing the high clock reference signal to obtain its pulse width, and the number of Burst pulses is obtained according to the pulse width.

[0022] Optionally, determining a corresponding gain balance mode in which the amplifier operates includes: determining a corresponding gain balance mode in which the amplifier operates by searching a gain mapping table, wherein the gain mapping table includes data corresponding to the number of Burst pulses and the gain balance mode.

[0023] Optionally, controlling the amplifier to operate in a corresponding gain balance mode includes:

[0024] controlling the first acousto-optic modulator to obtain consumption light from the laser pulse;

[0025] The amplifier is controlled to work in a corresponding gain balance mode by consuming its stored energy through the consumed light.

[0026] Based on the same inventive concept, the present application also provides a laser main control board of an ultrafast laser, comprising:

[0027] A signal acquisition unit, the signal acquisition unit is used to acquire a mode-locking signal and a first external trigger signal, and perform pulse width detection on the first external trigger signal according to the mode-locking signal to obtain a first Burst pulse number, the mode-locking signal is generated by a mode-locking oscillator according to laser pulse conversion of a repetition frequency, and the first external trigger signal is generated by a processing device according to a processing setting requirement;

[0028] a signal processing unit, the signal processing unit is used to determine the relationship between the pulse interval of the first external trigger signal and 1 / f0, where f0 is the reference frequency of the ultrafast laser; if the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the number of the first Burst pulses, the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the number of the first Burst pulses, the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light. The method comprises the steps of: obtaining a frequency-selective light from a laser pulse, controlling an amplifier to operate in a mode equal to the target gain and amplifying the frequency-selective light to obtain the amplified light, and controlling a second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is greater than 1 / f0, determining a first gain balancing mode in which the amplifier operates according to the number of the first Burst pulses and generating a third control signal, wherein the third control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, controlling the amplifier to operate in the first gain balancing mode and amplifying the frequency-selective light to obtain the amplified light, and controlling the second acousto-optic modulator to output the amplified light, wherein the first gain balancing mode makes the gain of the amplifier the same as the target gain.

[0029] Optionally, the signal processing unit is further used to determine that a switching control signal is generated when the ultrafast laser switches the number of Burst pulses, the switching control signal is used to control the second acousto-optic modulator to be turned off, and is used to control the amplifier to maintain a current gain mode; obtain a gain switching signal, the gain switching signal is generated by the processing equipment according to the second number of Burst pulses; determine a second gain balance mode of the amplifier according to the gain switching signal and generate a gain control signal, the gain control signal is used to control the amplifier to operate in a second gain balance mode, and the second gain balance mode makes the gain of the amplifier the same as the target gain;

[0030] The signal acquisition unit is used to acquire a second external trigger signal after a set time, wherein the second external trigger signal carries information about the number of the second Burst pulses; the second external trigger signal is subjected to pulse width detection according to the mode-locked signal to obtain the second number of Burst pulses; the signal processing unit is used to generate a fourth control signal according to the second number of Burst pulses, wherein the fourth control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, control the amplifier to operate in the second gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light.

[0031] Optionally, the signal acquisition unit includes:

[0032] A signal frequency multiplication module, the signal frequency multiplication module is used to obtain the mode-locking signal and multiply the mode-locking signal into a high clock reference signal;

[0033] A waveform pulse width calculation module is used to obtain the high clock reference signal and the corresponding external trigger signal, and use the high clock reference signal to process the external trigger signal to obtain its pulse width, and obtain the number of Burst pulses according to the pulse width.

[0034] Optionally, the laser main control board further includes a storage unit, the storage unit stores a gain mapping table, the gain mapping table includes data corresponding to the number of Burst pulses and the gain balance mode;

[0035] The signal processing unit determines the corresponding gain balance mode in which the amplifier operates, including: determining the corresponding gain balance mode in which the amplifier operates by searching the gain mapping table.

[0036] Compared with the prior art, the technical solution provided by this application has at least the following advantages:

[0037] The present application provides a control method for an ultrafast laser and its laser main control board, which establishes a timing reference through a mode-locked signal, and then performs pulse width detection on a corresponding external trigger signal according to the mode-locked signal to obtain a corresponding number of Burst pulses, thereby realizing a dynamic adjustment method for the number of Burst pulses and improving the response speed. Also, the frequency-selective light provided by the present application is selected from the laser pulse by the first acousto-optic modulator according to the corresponding number of Burst pulses, so that the repetition frequency of the laser pulse and the change of the number of Burst pulses are synchronized. In addition, the technical solution provided by the present application adjusts the gain balance mode of the amplifier according to the number of Burst pulses and the pulse interval of the external trigger signal. The gain balance mode makes the gain of the amplifier the same as the target gain, ensuring that the pulse energy remains stable under the condition of the current number of Burst pulses, and ultimately improving the performance of the ultrafast laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application 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 embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] Figure 1 It is a structural schematic diagram of an ultrafast laser in the prior art;

[0040] Figure 2 A schematic diagram of an output mode when the number of sub-pulses in a pulse train envelope is 2-5 in the prior art;

[0041] Figure 3 A schematic diagram of a method for implementing a Burst pulse number adjustment function in the prior art;

[0042] Figure 4 A flow chart of a method for controlling an ultrafast laser provided in an embodiment of the present application;

[0043] Figure 5 A schematic diagram of an ultrafast laser structure provided in an embodiment of the present application;

[0044] Figure 6 A flow chart of a control method for switching the number of Burst pulses provided in an embodiment of the present application;

[0045] Figure 7 A processing effect diagram corresponding to the switching of the number of Burst pulses when processing different materials provided in an embodiment of the present application;

[0046] Figure 8 A schematic diagram of the structure of a laser main control board of an ultrafast laser provided in an embodiment of the present application;

[0047] Fig. 9 A schematic diagram of the structure of a laser main control board of another ultrafast laser provided in an embodiment of the present application.

[0048] Reference numerals:

[0049] 10-mode-locked oscillator; 20-laser main control board; 30-first acousto-optic modulator; 40-amplifier; 50-second acousto-optic modulator; 60-processing equipment; 210-signal acquisition unit; 220-signal processing unit; 230-filtering unit; 240-storage unit; 211-signal frequency doubling module; 212-waveform pulse width calculation module. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] As mentioned in the background technology, the main structures of most existing ultrafast lasers are similar, such as Figure 1 As shown in the figure, the existing ultrafast laser is generally composed of a seed source, a pulse selector, an amplifier and an AOM. The structure of a femtosecond laser ultrafast laser is slightly more complicated. It is composed of a stretcher between the seed source and the pulse selector, and a compressor after the amplifier. Nowadays, the application fields of ultrafast lasers are becoming more and more extensive, such as material processing, medical treatment, scientific research, high-end equipment and other fields. Therefore, high-performance ultrafast lasers have extremely high application value and broader application prospects.

[0052] The number of burst pulses is one of the most important parameters in ultrafast lasers. The generation of burst is that the pulse selector selects several high-frequency pulses with the same frequency as the seed source to generate a pulse train and output it. Figure 2 The output mode when the number of sub-pulses in the pulse train envelope is 2-5 is listed. Its characteristics are that several sub-pulses with a spacing of tens of nanoseconds are grouped together, and the interval time between adjacent pulses in the pulse train envelope is determined by the oscillation frequency of the seed source; for example, if the frequency of the seed source is 50MHz, the pulse spacing of the internal structure of the pulse train is 1 / 50MHz=20ns, and the pulse repetition interval = single trigger-50MHz.

[0053] Further integration Figure 3The schematic diagram of the implementation of the Burst pulse number adjustment function shown in the figure, the seed source generates seed light, the laser main control board locks the reference signal of the seed light, and receives the external trigger signal provided by the processing board. The laser main control board controls the first acousto-optic modulator AOM1 to select the frequency-selected light from the seed light according to the phase-locked signal and the external trigger signal, and then the frequency-selected light enters the amplifier for amplification to form the amplified light, and the laser main control board finally controls the second acousto-optic modulator AOM2 to output the amplified light (output light). In this way, the Burst repetition frequency is PRI (Pulse Repetition Interval), and the number of Burst pulses is formed by the pulse width value given by the laser main control board to the first acousto-optic modulator AOM1. The number of Burst pulses is fixed in the system, and the change of the number of Burst pulses is changed by the pulse width value sent by the processing board to the laser main control board to the first acousto-optic modulator AOM1 through communication, so that the frequency of change of the number of Burst pulses is determined by the communication speed, which is usually at the millisecond level.

[0054] In the existing Burst pulse number adjustment function, the processing board or computer host sends a communication command to the laser main control board. After the laser main control board responds, it directly controls the pulse width to AOM1, which makes the number of Burst pulses of the ultrafast laser change too slowly, and makes the change of the pulse train repetition frequency PRI and the change of the number of Bursts not synchronized. In addition, although the existing technology uses the pulse width of the external trigger signal to obtain the number of Bursts, it does not solve the problem of amplifier gain fluctuation caused by changing the pulse train repetition frequency PRI and the number of Bursts; specifically, since the laser amplifier is pumped by continuous LD laser, the gain medium in the amplifier absorbs the continuous LD laser to store energy after pumping, and the more energy is stored, the higher the gain; and the pulse train repetition frequency PRI will affect the energy storage time, and different PRIs will cause different gains. Therefore, the change in the number of Burst pulses will have different energy storage consumption on the amplifier, and will also affect the gain of the amplifier, and the amplifier gain fluctuation will cause the laser pulse energy fluctuation, which ultimately makes the pulse energy of the ultrafast laser unstable.

[0055] Based on this, the embodiments of the present application provide a control method for an ultrafast laser and a laser main control board thereof, which effectively solve the existing technical problems and improve the performance of the ultrafast laser.

[0056] To achieve the above purpose, the technical solution provided in the embodiment of the present application is as follows, specifically combined with Figures 4 to 9 The technical solution provided in the embodiments of the present application is described in detail.

[0057] refer to Figure 4As shown, it is a flow chart of a control method of an ultrafast laser provided in an embodiment of the present application, wherein the control method of the ultrafast laser is completed based on a laser main control board, and the control method includes:

[0058] S1. Acquire a mode-locking signal and a first external trigger signal, wherein the mode-locking signal is generated by a mode-locking oscillator according to laser pulse conversion of a repetition frequency, and the first external trigger signal is generated by a processing device according to a processing setting requirement.

[0059] S2, performing pulse width detection on the first external trigger signal according to the mode-locked signal to obtain the number of first Burst pulses, and determining the relationship between the pulse interval of the first external trigger signal and 1 / f0, where f0 is the reference frequency of the ultrafast laser;

[0060] If the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the number of the first Burst pulses, and the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to work in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; at this time, the output pulse energy is less than the pulse energy output when the reference frequency f0 (that is, less than the pulse energy output when the pulse interval of the first external trigger signal is equal to 1 / f0), and the amplifier is in a safe state.

[0061] If the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the number of the first Burst pulses, and the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode equal to the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light;

[0062] If the pulse interval of the first external trigger signal is greater than 1 / f0, a first gain balance mode of the amplifier is determined according to the number of the first Burst pulses and a third control signal is generated, wherein the third control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, control the amplifier to operate in the first gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light, wherein the first gain balance mode makes the gain of the amplifier the same as the target gain.

[0063] As can be seen from the above content, the technical solution provided in the embodiment of the present application establishes a timing reference through a mode-locked signal, and then performs pulse width detection on the corresponding external trigger signal according to the mode-locked signal to obtain the corresponding number of Burst pulses, thereby realizing a dynamic adjustment method for the number of Burst pulses and improving the response speed. In addition, the frequency-selective light provided in the embodiment of the present application is selected from the laser pulse by the first acousto-optic modulator according to the corresponding number of Burst pulses, so that the repetition frequency of the laser pulse and the change of the number of Burst pulses are synchronized. In addition, the technical solution provided in the embodiment of the present application adjusts the gain balance mode of the amplifier according to the number of Burst pulses and the pulse interval of the external trigger signal. The gain balance mode makes the gain of the amplifier the same as the target gain, ensuring that the pulse energy remains stable under the condition of the current number of Burst pulses, and ultimately improving the performance of the ultrafast laser.

[0064] Specific combination Figure 5As shown, it is a schematic diagram of the structure of an ultrafast laser provided in an embodiment of the present application, wherein the ultrafast laser includes a mode-locked oscillator 10, a laser main control board 20, a first acousto-optic modulator 30, an amplifier 40, a second acousto-optic modulator 50 and a processing device 60, and the processing device 60 can be a processing board or a computer host, etc. When the ultrafast laser is working, the mode-locked oscillator 10 generates a mode-locked signal according to the laser pulse conversion of the repetition frequency and sends it to the laser main control board 20, and the processing equipment 60 generates a first external trigger signal according to the processing setting requirements and sends it to the laser main control board 20; the laser main control board 20 obtains the mode-locked signal and the first external trigger signal, and then performs pulse width detection on the first external trigger signal according to the mode-locked signal to obtain the first Burst pulse number, and judges the relationship between the pulse interval of the first external trigger signal and 1 / f0, f0 is the reference frequency of the ultrafast laser; if the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the first Burst pulse number, and the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to work in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; if the first external trigger If the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the first number of Burst pulses, and the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to work in a mode equal to the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is greater than 1 / f0, the first gain balance mode in which the amplifier 40 works is determined according to the first number of Burst pulses and a third control signal is generated, and the third control signal is used to control the first acousto-optic modulator 30 to obtain the frequency-selective light from the laser pulse, control the amplifier 40 to work in the first gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator 50 to output the amplified light, wherein the first gain balance mode makes the gain of the amplifier 40 the same as the target gain.

[0065] The mode-locked oscillator 10 provided in the embodiment of the present application generates picosecond or femtosecond laser pulses with a repetition frequency of tens of MHz (such as 20MHz-80MHz), and processes the laser pulses into a mode-locked signal through the photodetector therein; the mode-locked oscillator 10 can be a solid structure or an optical fiber structure. The processing equipment 60 can be a processing board or a computer host. The processing equipment 60 controls the motion mechanism of the processing equipment according to its internal clock signal, and generates a corresponding external trigger signal according to the processing position and processing setting requirements (such as processing point interval, processing speed and other parameters), such as a PSO external trigger signal or a POD external trigger signal. Optionally, the external trigger signal can be filtered by a filtering unit and then transmitted to the laser main control board 20, wherein the filtering unit can be integrated into the laser main control board 20, or the filtering unit can be integrated into the processing equipment 60, or the filtering unit can be an independent device independent of the laser main control board 20 and the processing equipment 60.

[0066] After the laser main control board 20 obtains the mode-locking signal and the external trigger signal, the laser main control board 20 processes them to generate corresponding control signals to control the first AOM 30, the amplifier 40 and the second AOM 50. The repetition frequency of the radio frequency of the first AOM 30 is generally 200MHz-300MHz, and its response speed is relatively fast. Therefore, the laser main control board 20 can delay the control signal to be sent to the first AOM 30 to ensure that the frequency-selective light output by the first AOM 30 can be released after the second AOM 50 is turned on, wherein the delay time can be a fixed time or determined according to the turn-on time of the second AOM 50. Among them, the acousto-optic modulator is a radio frequency device, which is used for a laser pulse selection device; the first acousto-optic modulator 30 is used to select the corresponding frequency-selective light (such as 1Hz-2MHz) in the laser pulse according to the control signal; and the second acousto-optic modulator 50 is used to release the amplified light output by the amplifier 40 according to the control signal. Since the control signal is generated according to the number of Burst pulses, and the number of Burst pulses is obtained with reference to the external trigger signal, the external trigger signal determines the repetition frequency of the frequency-selective light and the number of Burst pulses.

[0067] The generation of the control signal of the laser main control board 20 not only needs to refer to the number of Burst pulses, but also needs to refer to the reference frequency f0. The reference frequency f0 is determined according to the parameters of the ultrafast laser. For example, when the ultrafast laser needs to output 100W / 100uJ / 100kHz laser parameters, the reference frequency f0 can be set to 100kHz. The difference in the reference frequency f0 determines the different gain capabilities of the ultrafast laser, and the different numbers of Burst pulses also make the gain capabilities of the ultrafast laser different. Therefore, it is necessary to control the amplifier in different gain balance modes, thereby ensuring that the pulse energy remains stable under the current number of Burst pulses, and ultimately improving the performance of the ultrafast laser. That is, the embodiment of the present application adjusts the gain balance mode of the amplifier so that the output laser pulse energy is basically the same as that at the reference frequency f0 when the frequency is lower than the reference frequency f0. For example, when the number of Burst pulses is 1 and the reference frequency is 100kHz, the amplifier operates in the target gain mode so that the pulse energy is 100μJ. When the frequency is 90kHz (lower than the reference frequency 100kHz), the amplifier is controlled to operate in the corresponding gain balance mode so that the pulse energy is about 100μJ. When the frequency is 20kHz (lower than the reference frequency 100kHz), the amplifier is controlled to operate in the corresponding gain balance mode so that the pulse energy is about 100μJ. J; or when the number of Burst pulses is 2, the reference frequency is 100kHz, the amplifier works in the target gain mode so that the pulse energy is 120μJ (the sum of the energies of the two pulses), the frequency is 90kHz (100kHz lower than the reference frequency), the amplifier is controlled to work in the corresponding gain balance mode so that the pulse energy is about 120μJ, and the frequency is 20kHz (100kHz lower than the reference frequency) The amplifier is controlled to work in the corresponding gain balance mode so that the pulse energy is about 120μJ; or when the number of Burst pulses is N, the reference frequency is 100kHz, and the amplifier works in the target gain mode so that the pulse energy is E N , the control amplifier operates in the corresponding gain balance mode at a frequency of 90kHz (lower than the reference frequency of 100kHz) so that the pulse energy is approximately E N , the control amplifier operates in the corresponding gain balance mode at a frequency of 20kHz (lower than the reference frequency of 100kHz) so that the pulse energy is approximately E N .

[0068] Furthermore, when the ultrafast laser provided in the embodiment of the present application switches the number of Burst pulses, the gain balance mode of the amplifier can be changed in advance, thereby avoiding the problem of amplifier gain fluctuation after switching the number of Burst pulses, and improving the working stability of the ultrafast laser. Figure 6As shown, it is a flow chart of a control method for switching the number of Burst pulses provided in an embodiment of the present application, wherein, when the ultrafast laser switches the first number of Burst pulses to the second number of Burst pulses, the control method includes:

[0069] S31, determining that a switching control signal is generated when the ultrafast laser switches the number of Burst pulses, wherein the switching control signal is used to control the second acousto-optic modulator to be turned off, and is used to control the amplifier to maintain a current gain mode.

[0070] In an embodiment of the present application, the determination of switching the number of Burst pulses of the ultrafast laser provided in the embodiment of the present application may include: detecting that the processing equipment stops outputting the first external trigger signal, and at this time judging that the pulse interval is greater than 1 / f0, then determining that the ultrafast laser switches the number of Burst pulses. In order to maintain gain balance, the amplifier maintains the current gain mode, such as the amplifier operating in the corresponding gain balance mode to consume the amplifier's stored energy.

[0071] S32. Obtain a gain switching signal, where the gain switching signal is generated by the processing equipment according to the number of the second Burst pulses.

[0072] S33. Determine a second gain balance mode of the amplifier according to the gain switching signal and generate a gain control signal, wherein the gain control signal is used to control the amplifier to operate in a second gain balance mode, wherein the second gain balance mode makes the gain of the amplifier the same as the target gain.

[0073] S34. Obtain a second external trigger signal after a set time, where the second external trigger signal carries information about the number of the second Burst pulses.

[0074] S35. Perform pulse width detection on the second external trigger signal according to the mode-locked signal to obtain the second Burst pulse number, and generate a fourth control signal according to the second Burst pulse number, wherein the fourth control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, control the amplifier to operate in the second gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light.

[0075] It can be understood that when the ultrafast laser provided in the embodiment of the present application switches the number of Burst pulses, if the processing equipment 60 needs to change the current first number of Burst pulses to the required second number of Burst pulses, the laser main control board 20 will first determine the switching state and generate a switching control signal to control the second acousto-optic modulator 50 to be turned off, and control the amplifier 40 to maintain the current gain mode (such as working in the current target gain mode, or working in the current gain balance mode); then the processing equipment 60 will send the gain switching signal to the laser main control board 20, and the laser main control board 20 will determine the second gain balance mode of the amplifier 40 according to the signal of the second number of Burst pulses carried by the gain switching signal, and control the amplifier 40 to work in the second gain balance mode; to be set After a certain period of time, the gain of the amplifier 40 is stable, and the processing equipment 60 will send the second external trigger signal to the laser main control board 20. The laser main control board 20 processes the second external trigger signal to obtain the second number of Burst pulses; then the laser main control board 20 generates a fourth control signal according to the second number of Burst pulses to control the first acousto-optic modulator 30 to obtain the frequency-selective light from the laser pulse, control the amplifier 40 to work in the second gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator 50 to output the amplified light, thereby completing the control of the switching of the number of Burst pulses. Since the gain of the amplifier 40 is stabilized before the processing equipment 60 sends the second external trigger signal, the problem of gain fluctuation of the amplifier 40 after switching the number of Burst pulses is avoided, thereby improving the working stability of the ultrafast laser.

[0076] In any of the above embodiments, the pulse width detection of the corresponding external trigger signal according to the mode-locked signal provided in the embodiment of the present application obtains the number of Burst pulses, including: multiplying the mode-locked signal to a high clock reference signal; using the high clock reference signal to process the external trigger signal to obtain its pulse width, and obtaining the number of Burst pulses according to the pulse width. The ultrafast laser internally stores mapping data of pulse width and number of Burst pulses, and different pulse widths correspond to different numbers of Burst pulses, such as 200ns pulse width corresponds to 4 Burst pulses, 230ns pulse width corresponds to 5 Burst pulses, etc. Therefore, by determining the number of Burst pulses by pulse width, the response speed of the ultrafast laser can be improved.

[0077] In any of the above embodiments, the embodiment of the present application provides a method for determining the corresponding gain balance mode of the amplifier operation, including: determining the corresponding gain balance mode of the amplifier operation by searching a gain mapping table, wherein the gain mapping table includes the number of Burst pulses and the corresponding data of the gain balance mode. Then, after determining the response gain balance mode of the amplifier operation, controlling the amplifier to operate in the corresponding gain balance mode includes: controlling the first acousto-optic modulator to obtain the consumption light from the laser pulse; controlling the amplifier to operate in the corresponding gain balance mode by consuming its energy storage through the consumption light, that is, consuming the energy storage of the amplifier through the consumption light (the consumption light can be pulse light or continuous light), thereby ensuring that the amplifier gain capability is consistent with the frequency-selective light amplification under the reference frequency f0 condition. Since the gain capability of the amplifier will change under different numbers of Burst pulses, the gain balance mode corresponding to different numbers of Burst pulses is also different. For this reason, it is necessary to adjust the intensity of the consumption light according to different gain balance modes, so as to finally achieve the purpose of making the amplifier gain capability consistent with the frequency-selective light amplification under the reference frequency f0 condition.

[0078] That is to say, the control method provided in the embodiment of the present application sets the reference frequency f0, and then compares the pulse interval of the external trigger signal with 1 / f0. When the pulse interval of the external trigger signal is greater than 1 / f0, the corresponding gain balance mode is searched from the gain mapping table according to the number of Burst pulses corresponding to the external trigger signal to control the amplifier to operate in the gain balance mode. If the pulse interval of the first external trigger signal is greater than 1 / f0, the first number of Burst pulses is found in the gain mapping table to correspond to the first gain balance mode, and the amplifier is controlled to operate in the first gain balance mode;

[0079] The pulse interval of the second external trigger signal is greater than 1 / f0, and the second Burst pulse number corresponds to the second gain balance mode when it is found in the gain mapping table, and the amplifier is controlled to work in the second gain balance mode;

[0080] The pulse interval of the third external trigger signal is greater than 1 / f0, and the third Burst pulse number corresponds to the third gain balance mode when it is found in the gain mapping table, and the amplifier is controlled to work in the third gain balance mode;

[0081] By analogy, the pulse interval of the Nth external trigger signal is greater than 1 / f0, and the number of NBurst pulses corresponding to the Nth gain balance mode is found in the gain mapping table, and the control amplifier works in the Nth gain balance mode, where N is a positive integer.

[0082] When the number of Burst pulses needs to be switched during the operation of the ultrafast laser, the processing equipment has no external trigger signal input to the laser main control board, the amplifier works in the current gain mode, and the second acousto-optic modulator is controlled to be turned off. Due to changes in processing requirements, the processing equipment needs to change the number of Burst pulses. The processing equipment sends a gain switching signal to the laser main control board. The laser main control board controls the amplifier to work in the gain balance mode corresponding to the changed number of Burst pulses according to the gain switching signal. After waiting for a set time for the amplifier gain to stabilize, the processing equipment sends a new external trigger signal to the laser main control board for subsequent work. Figure 7 As shown in the figure, it is a processing effect diagram corresponding to the switching of the number of Burst pulses when processing different materials provided by an embodiment of the present application. When the processing is switched from material A (material B) to material B (material A), the number of Burst pulses quickly changes from the number of A (B) to the number of B (A), and the processing efficiency is significantly improved. After the number of Burst pulses is switched, the pulse energy output by the ultrafast laser is stable, and there is no high or low energy pulse output, and the processing effect is better.

[0083] Based on the control method provided in any of the above embodiments, the present application also provides a laser main control board for an ultrafast laser. Figure 8 As shown, it is a structural schematic diagram of a laser main control board of an ultrafast laser controller provided in an embodiment of the present application, wherein the laser main control board 20 includes: a signal acquisition unit 210, the signal acquisition unit 210 is used to acquire a mode-locking signal and a first external trigger signal, and perform pulse width detection on the first external trigger signal according to the mode-locking signal to obtain the first Burst pulse number, the mode-locking signal is generated by the mode-locking oscillator 10 according to the laser pulse conversion of the repetition frequency, and the first external trigger signal is generated by the processing equipment 60 according to the processing setting requirements.

[0084] The invention also includes a signal processing unit 220, wherein the signal processing unit 220 is used to determine the relationship between the pulse interval of the first external trigger signal and 1 / f0, where f0 is the reference frequency of the ultrafast laser; if the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the number of the first Burst pulses, wherein the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the number of the first Burst pulses, wherein the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light. The method comprises the steps of: obtaining a frequency-selective light from the laser pulse, controlling the amplifier to operate in a mode equal to the target gain and amplifying the frequency-selective light to obtain the amplified light, and controlling the second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is greater than 1 / f0, determining a first gain balancing mode in which the amplifier operates according to the number of the first Burst pulses and generating a third control signal, wherein the third control signal is used to control the first acousto-optic modulator 30 to obtain the frequency-selective light from the laser pulse, controlling the amplifier 40 to operate in the first gain balancing mode and amplifying the frequency-selective light to obtain the amplified light, and controlling the second acousto-optic modulator 50 to output the amplified light, wherein the first gain balancing mode makes the gain of the amplifier 40 the same as the target gain.

[0085] Furthermore, when the ultrafast laser provided in the embodiment of the present application switches the number of Burst pulses, the gain balance mode of the amplifier can be changed in advance, thereby avoiding the problem of amplifier gain fluctuation after switching the number of Burst pulses, and improving the working stability of the ultrafast laser. That is, the signal processing unit 220 provided in the embodiment of the present application is also used to determine that the ultrafast laser generates a switching control signal when the number of Burst pulses is switched, and the switching control signal is used to control the second acousto-optic modulator to turn off, and is used to control the amplifier to maintain the current gain mode; obtain a gain switching signal, and the gain switching signal is generated by the processing equipment according to the second number of Burst pulses; determine the second gain balance mode of the amplifier according to the gain switching signal and generate a gain control signal, and the gain control signal is used to control the amplifier to operate in the second gain balance mode, and the second gain balance mode makes the gain of the amplifier consistent with the target gain. The signal acquisition unit 210 is used to acquire a second external trigger signal after a set time, and the second external trigger signal carries the second Burst pulse number information; the second external trigger signal is subjected to pulse width detection according to the mode-locked signal to obtain the second Burst pulse number; the signal processing unit 220 is used to generate a fourth control signal according to the second Burst pulse number, and the fourth control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, control the amplifier to work in the second gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light.

[0086] refer to Fig. 9 As shown, it is a structural schematic diagram of another laser main control board of an ultrafast laser provided in an embodiment of the present application, wherein the signal acquisition unit 210 includes: a signal frequency doubling module 211, the signal frequency doubling module is used to acquire the mode-locked signal, and multiply the mode-locked signal into a high clock reference signal; a waveform pulse width calculation module 212, the waveform pulse width calculation module 212 is used to acquire the high clock reference signal and the corresponding external trigger signal, and use the high clock reference signal to process the external trigger signal to obtain its pulse width, and obtain the number of Burst pulses according to the pulse width. Optionally, the laser main control board 20 also includes a filtering unit 230, the filtering unit 230 is used to filter the trigger signal and send it to the waveform pulse width calculation module 212.

[0087] In any of the above embodiments, the gain balance mode provided in the embodiment of the present application can be obtained by looking up a table. Fig. 9As shown, the laser main control board 20 provided in the embodiment of the present application also includes a storage unit 240, and the storage unit 240 stores a gain mapping table, and the gain mapping table includes the corresponding data of the number of Burst pulses and the gain balance mode; the signal processing unit 220 determines the corresponding gain balance mode of the amplifier 40, including: determining the corresponding gain balance mode of the amplifier 40 by searching the gain mapping table.

[0088] The embodiment of the present application provides a control method for an ultrafast laser and its laser main control board, which establishes a timing reference through a mode-locked signal, and then performs pulse width detection on the corresponding external trigger signal according to the mode-locked signal to obtain the corresponding number of Burst pulses, thereby realizing a dynamic adjustment method for the number of Burst pulses and improving the response speed. In addition, the frequency-selective light provided in the embodiment of the present application is selected from the laser pulse by the first acousto-optic modulator according to the corresponding number of Burst pulses, so that the repetition frequency of the laser pulse and the change of the number of Burst pulses are synchronized. In addition, the technical solution provided in the embodiment of the present application adjusts the gain balance mode of the amplifier according to the number of Burst pulses and the pulse interval of the external trigger signal. The gain balance mode makes the gain of the amplifier the same as the target gain, ensuring that the pulse energy remains stable under the condition of the current number of Burst pulses, and ultimately improving the performance of the ultrafast laser.

[0089] In the description of the embodiments of the present application, it needs to be understood that the orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0090] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0091] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0092] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0093] In the embodiments of the present application, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

[0094] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for controlling an ultrafast laser, characterized in that: include: Acquire a mode-locking signal and a first external trigger signal, wherein the mode-locking signal is generated by a mode-locking oscillator according to laser pulse conversion of a repetition frequency, and the first external trigger signal is generated by a processing device according to a processing setting requirement; Performing pulse width detection on the first external trigger signal according to the mode-locked signal to obtain the number of first Burst pulses, and determining the relationship between the pulse interval of the first external trigger signal and 1 / f0, where f0 is the reference frequency of the ultrafast laser; If the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the number of the first Burst pulses, wherein the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than a target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; If the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the number of the first Burst pulses, and the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode equal to the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; If the pulse interval of the first external trigger signal is greater than 1 / f0, a first gain balance mode of the amplifier is determined according to the number of the first Burst pulses and a third control signal is generated, wherein the third control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, control the amplifier to operate in the first gain balance mode and amplify the frequency-selective light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light, wherein the first gain balance mode makes the gain of the amplifier the same as the target gain.

2. The control method of the ultrafast laser according to claim 1, characterized in that: When the ultrafast laser switches the first number of Burst pulses to a second number of Burst pulses, the control method includes: Determining that the ultrafast laser generates a switching control signal when switching the number of Burst pulses, wherein the switching control signal is used to control the second acousto-optic modulator to be turned off and to control the amplifier to maintain a current gain mode; Acquire a gain switching signal, where the gain switching signal is generated by the processing equipment according to the number of the second Burst pulses; Determine a second gain balance mode of the amplifier according to the gain switching signal and generate a gain control signal, wherein the gain control signal is used to control the amplifier to operate in the second gain balance mode, wherein the second gain balance mode makes the gain of the amplifier the same as the target gain; After a set time, a second external trigger signal is obtained, where the second external trigger signal carries information about the number of the second Burst pulses; The second external trigger signal is subjected to pulse width detection according to the mode-locked signal to obtain the second Burst pulse number, and a fourth control signal is generated according to the second Burst pulse number, wherein the fourth control signal is used to control the first acousto-optic modulator to obtain the frequency-selected light from the laser pulse, control the amplifier to operate in the second gain balance mode and amplify the frequency-selected light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light.

3. The control method of the ultrafast laser according to claim 2, characterized in that: The step of determining that the ultrafast laser performs Burst pulse number switching includes: When it is detected that the processing equipment stops outputting the first external trigger signal, it is determined that the ultrafast laser switches the number of Burst pulses.

4. The method for controlling an ultrafast laser according to any one of claims 1 to 3, characterized in that: The pulse width of the corresponding external trigger signal is detected according to the mode-locked signal to obtain the number of Burst pulses, including: Multiplying the mode-locked signal to a high clock reference signal; The external trigger signal is processed by utilizing the high clock reference signal to obtain its pulse width, and the number of Burst pulses is obtained according to the pulse width.

5. The method for controlling an ultrafast laser according to any one of claims 1 to 3, characterized in that: Determining the corresponding gain balance mode of the amplifier includes: determining the corresponding gain balance mode of the amplifier by searching a gain mapping table, wherein the gain mapping table includes data corresponding to the number of Burst pulses and the gain balance mode.

6. The method for controlling an ultrafast laser according to any one of claims 1 to 3, characterized in that: Controlling the amplifier to operate in a corresponding gain balance mode, comprising: controlling the first acousto-optic modulator to obtain consumption light from the laser pulse; The amplifier is controlled to work in a corresponding gain balance mode by consuming its stored energy through the consumed light.

7. A laser main control board for an ultrafast laser, characterized in that: include: A signal acquisition unit, the signal acquisition unit is used to acquire a mode-locking signal and a first external trigger signal, and perform pulse width detection on the first external trigger signal according to the mode-locking signal to obtain a first Burst pulse number, the mode-locking signal is generated by a mode-locking oscillator according to laser pulse conversion of a repetition frequency, and the first external trigger signal is generated by a processing device according to a processing setting requirement; a signal processing unit, the signal processing unit is used to determine the relationship between the pulse interval of the first external trigger signal and 1 / f0, where f0 is the reference frequency of the ultrafast laser; if the pulse interval of the first external trigger signal is less than 1 / f0, a first control signal is generated according to the number of the first Burst pulses, the first control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is equal to 1 / f0, a second control signal is generated according to the number of the first Burst pulses, the second control signal is used to control the first acousto-optic modulator to obtain frequency-selective light from the laser pulse, control the amplifier to operate in a mode less than the target gain and amplify the frequency-selective light to obtain amplified light, and control the second acousto-optic modulator to output the amplified light. The method comprises the steps of: obtaining a frequency-selective light from a laser pulse, controlling an amplifier to operate in a mode equal to the target gain and amplifying the frequency-selective light to obtain the amplified light, and controlling a second acousto-optic modulator to output the amplified light; if the pulse interval of the first external trigger signal is greater than 1 / f0, determining a first gain balancing mode in which the amplifier operates according to the number of the first Burst pulses and generating a third control signal, wherein the third control signal is used to control the first acousto-optic modulator to obtain the frequency-selective light from the laser pulse, controlling the amplifier to operate in the first gain balancing mode and amplifying the frequency-selective light to obtain the amplified light, and controlling the second acousto-optic modulator to output the amplified light, wherein the first gain balancing mode makes the gain of the amplifier the same as the target gain.

8. The laser main control board of the ultrafast laser according to claim 7, characterized in that: The signal processing unit is further used to determine that a switching control signal is generated when the ultrafast laser switches the number of Burst pulses, and the switching control signal is used to control the second acousto-optic modulator to be turned off, and is used to control the amplifier to maintain a current gain mode; obtain a gain switching signal, and the gain switching signal is generated by the processing equipment according to the second number of Burst pulses; determine a second gain balance mode of the amplifier according to the gain switching signal and generate a gain control signal, and the gain control signal is used to control the amplifier to work in the second gain balance mode, and the second gain balance mode makes the gain of the amplifier the same as the target gain; The signal acquisition unit is used to acquire a second external trigger signal after a set time, wherein the second external trigger signal carries information about the number of the second Burst pulses; and to perform pulse width detection on the second external trigger signal according to the mode-locked signal to obtain the number of the second Burst pulses; The signal processing unit is used to generate a fourth control signal according to the number of the second Burst pulses, and the fourth control signal is used to control the first acousto-optic modulator to obtain the frequency-selected light from the laser pulse, control the amplifier to operate in the second gain balance mode and amplify the frequency-selected light to obtain the amplified light, and control the second acousto-optic modulator to output the amplified light.

9. The laser main control board of the ultrafast laser according to claim 7 or 8, characterized in that: The signal acquisition unit comprises: A signal frequency multiplication module, the signal frequency multiplication module is used to obtain the mode-locking signal and multiply the mode-locking signal into a high clock reference signal; A waveform pulse width calculation module is used to obtain the high clock reference signal and the corresponding external trigger signal, and use the high clock reference signal to process the external trigger signal to obtain its pulse width, and obtain the number of Burst pulses according to the pulse width.

10. The laser main control board of the ultrafast laser according to claim 7 or 8, characterized in that: The laser main control board also includes a storage unit, the storage unit stores a gain mapping table, the gain mapping table includes the number of Burst pulses and the corresponding data of the gain balance mode; The signal processing unit determines the corresponding gain balance mode in which the amplifier operates, including: determining the corresponding gain balance mode in which the amplifier operates by searching the gain mapping table.

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