Laser pulse shaping system

Abstract

The invention discloses a laser pulse shaping system which comprises a pulse input module, at least two optical modulation switches and a pulse output module. The pulse input module inputs a source pulse, the source pulse is switched and modulated through at least two optical modulation switches to form a modulation pulse, and the modulation pulse is output through the pulse output module; and shaping the source pulse by controlling and adjusting parameters of the first optical modulation switch and / or the second optical modulation switch to obtain a modulation pulse in any required shape.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers, and particularly to a laser pulse shaping system. Background Art

[0002] For high-energy lasers, pulse shaping is of crucial significance. During the operation of high-energy lasers, due to the characteristic of continuous energy storage of the gain medium, when amplifying a train of laser pulses, the amplification effect of the first few pulses of the train of laser pulses, especially the energy of the first pulse, is always significantly higher than that of the subsequent stable pulses. This non-uniform energy amplification phenomenon greatly affects the quality of pulse output. With the progress of laser technology, the application fields of lasers have also been continuously expanded. In applications such as laser microfabrication and laser medicine, higher requirements are put forward for the consistency of laser pulse energy output.

[0003] Currently, in order to make the output pulse energy consistent, there are mainly two methods. One is to suppress the energy of the first pulse or the first few pulses of the amplified output train of laser pulses through pulse width adjustable technology; the other is to filter out the over-amplified pulses by means of loss or interception. Compared with the latter, the former has a higher utilization rate of pulses, a higher utilization rate of the overall system, and is more advantageous. The former mainly targets regular pulse trains. After pre-testing, the amplitude of each pulse is detected one by one, and the pulses with a large difference from the standard value are suppressed until the pulse amplitude is lower than the set threshold, and the relevant parameters are recorded for subsequent work. However, the entire system is complex in structure and only applicable to regular and stable pulse trains. When the output pulse train changes, re-detection is required, which not only increases the complexity of operation but also may lead to long-term downtime, affecting production efficiency.

[0004] The above two methods are both to adjust the amplified output pulses to make them consistent, and the systems are both relatively complex and inefficient. Therefore, for those skilled in the art, it is urgent to develop a laser pulse shaping system with simple operation, flexibility and high efficiency. Summary of the Invention

[0005] Aiming at the above defects of the existing laser pulse shaping, the present invention proposes a laser pulse shaping system. The shaping system shapes the input source pulses before laser pulse amplification to obtain modulated pulses of any target shape by controlling and adjusting the parameters of at least two optical modulation switches, and has the advantages of flexible operation, simplicity and high efficiency.

[0006] The present invention provides a laser pulse shaping system, including a pulse input module, at least two optical modulation switches and a pulse output module;

[0007] The pulse input module inputs a source pulse, which enters the pulse output module after being switched and modulated by at least two optical modulation switches, and the pulse output module outputs a modulated pulse.

[0008] By controlling and adjusting the parameters of the optical modulation switches, the source pulse is shaped to obtain a modulated pulse that conforms to the target pulse shape.

[0009] As a preferred embodiment, the laser pulse shaping system further includes:

[0010] A detection and feedback module, which is used to detect whether the modulated pulse formed after the source pulse is switched and modulated by at least two optical modulation switches is within a preset range. If it is within the preset range, the modulation quality is qualified; otherwise, the modulation quality is unqualified.

[0011] As a preferred embodiment, the laser pulse shaping system further includes: a controller for controlling the optical modulation switches, and the detection and feedback module is connected to the controller;

[0012] When the modulation quality of the modulated pulse is unqualified, it is fed back to the controller, and the parameters of at least one optical modulation switch are reselected and adjusted until the modulated pulse formed is within the preset range.

[0013] As a preferred embodiment, the target pulse is the pulse after being amplified by a laser.

[0014] As a preferred embodiment, the parameters of the optical modulation switches include the number of modulation switches, the working time, and the response time.

[0015] As a preferred embodiment, the optical modulation switch includes an acousto-optic modulator or an electro-optic modulator.

[0016] As a preferred embodiment, the source pulse is a seed source laser pulse.

[0017] As a preferred embodiment, the optical modulation switch includes a modulation switch driven by an analog signal or a digital signal.

[0018] As a preferred embodiment, the preset range is set according to the pulse shape required for laser amplification, and the range of the preset modulated pulse is inversely deduced. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the laser pulse shaping system proposed in the embodiment of the present invention;

[0020] Figure 2Schematic structural diagram of the laser pulse shaping system proposed in another embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the pulse change shape of the laser pulse shaping system proposed in an embodiment of the present invention;

[0022] Figure 4 Schematic diagram of the pulse change shape of the laser pulse shaping system proposed in another embodiment of the present invention;

[0023] Figure 5 Characteristic diagram of the optical modulation switch of the laser pulse shaping system proposed in an embodiment of the present invention;

[0024] Figure 6a Schematic diagram of the pulse energy after being modulated by the first optical modulation switch driven by an analog signal in an embodiment of the present invention;

[0025] Figure 6b Schematic diagram of the pulse energy after being modulated by the second optical modulation switch driven by a digital signal in an embodiment of the present invention.

[0026] Reference numerals:

[0027] 1. Pulse input module; 2. Optical modulation switch; 21. First optical modulation switch driven by an analog signal; 22. Second optical modulation switch driven by a digital signal; 3. Pulse output module; 4. Detection and feedback module; 5. Controller. Detailed implementation manners

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] It should be noted that unless otherwise defined, the up, down, left, right, etc. directions involved in this article are based on the up, down, left, right, etc. directions illustrated in the embodiments of this application. If the specific posture changes, the directional indication will also change accordingly. The "first", "second", "third", "fourth", and similar terms used in this application do not indicate any order, quantity, or importance, but are only used to distinguish different components. In addition, in various embodiments of the present disclosure, the same or similar reference numerals represent the same or similar components.

[0030] In this application, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral one, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] In addition, the technical solutions between various embodiments of this application can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this invention.

[0032] The following content is all examples of the specific implementation process provided to elaborate in detail the technical solution to be protected by this application. However, this application can also be implemented in other ways different from the described ones. Those skilled in the art can, under the guidance of the concept of this application, adopt different technical means to implement this application. Therefore, this application is not limited by the following specific embodiments.

[0033] In view of the above defects and improvement requirements of the existing laser pulse shaping, the present invention proposes a novel laser pulse shaping system.

[0034] See Figure 1 , a laser pulse shaping system, including a pulse input module 1, at least two optical modulation switches 2, and a pulse output module 3;

[0035] The pulse input module 3 inputs a source pulse, which passes through at least two optical modulation switches 2 for switching and modulation and then enters the pulse output module 3. The pulse output module 3 outputs a modulated pulse of any desired shape by modulating at least two optical modulation switches.

[0036] It should be noted that the source pulse refers to the radio frequency pulse signal generated by a laser seed source, which is the initial optical signal provided for the laser. The core improvement point of the pulse shaping system of the present invention is that the shaping system directly shapes the initial optical signal, that is, shapes the source pulse, and directly performs switching and modulation shaping through at least two optical modulation switches to obtain a modulated pulse of any desired shape, and then outputs it through the pulse output module 3. This modulated pulse is also the input pulse of the laser amplification system. After passing through the high-energy laser amplification system, a target pulse with a pulse energy meeting the requirements can be obtained.

[0037] Continue to refer to Figure 1, at least two of the optical modulation switches 2 are composed of a plurality of first optical modulation switches 21 driven by analog signals, or are composed of a plurality of second optical modulation switches 22 driven by digital signals, or are composed of at least one first optical modulation switch 21 driven by an analog signal and at least one second optical modulation switch 22 driven by a digital signal, and the optical modulation switches are connected in series;

[0038] According to the parameter data of the target pulse, by controlling and adjusting the parameters of the first optical modulation switch and / or the second optical modulation switch, a modulation pulse meeting the required pulse shape standard is obtained, and the pulse shape standard is within the preset range of the preset modulation pulse.

[0039] Specifically, the parameter data of the target pulse includes the pulse shape and the number of pulses. According to the pulse shape and the number of pulses of the target pulse, the pulse shape and the number of pulses of the preset modulation pulse are deduced inversely. According to the pulse shape and the number of pulses of the preset modulation pulse, the number, working time and response time of the optical modulation switches are selected and controlled to obtain a modulation pulse meeting the preset range of the preset modulation pulse.

[0040] Further, the implementation method for obtaining a modulation pulse meeting the preset range of the preset modulation pulse includes establishing an algorithm model of the modulation pulse:

[0041] Input: the pulse shape (shape) and the number of pulses (count) of the preset modulation pulse;

[0042] Output: the number (numSwitch) of the optical modulation switches, the working time (workTime) of each optical modulation switch, the response time (responseTime) of each optical modulation switch, and after being modulated and shaped by a plurality of optical modulation switches, a modulation pulse meeting the pulse shape standard (modulatedPulse) is output;

[0043] The specific steps include:

[0044] Step 1. According to the input pulse shape (shape) and the number of modulation pulses (count) of the preset modulation pulse, calculate the required total energy (totalEnergy).

[0045] Step 2. According to the total energy (totalEnergy) and the pre-set energy (energy) distribution strategy of the optical modulation switches, determine the number (numSwitch) of the optical modulation switches, for example: numSwitch = totalEnergy / energy.

[0046] Step 3. According to the energy (energy1, energy2......energyN) allocated to each optical modulation switch and the known output energy per unit time of each optical modulation switch (E1, E2......En), calculate the working time (workTime1, workTime2......workTimeN) and response time (responseTime1, responseTime2......responseTimeN) of each optical modulation switch, so as to output a modulation pulse with a standard pulse shape.

[0047] Of course, an iterative algorithm can also be used. Starting from the initially estimated number of switches and working time of the optical modulation switch, gradually adjust and compare the generated pulse energy with the required standard pulse shape until the error range is met.

[0048] For example, assume that the energy allocated to an optical modulation switch is energy1, the known output energy per unit time of this optical modulation switch is E1, and the energy conversion efficiency is efficiency. Then the initially estimated working time of this optical modulation switch is workTime1 = energy1 / E1, and the response time is responseTime1 = energy1 * (1 - efficiency) / E1).

[0049] Similarly, according to the energy allocated to other optical modulation switches and the known output energy per unit time and energy conversion efficiency of the optical modulation switches, calculate the number, working time, and response time of other optical modulation switches, so as to output a modulation pulse (modulatedPulse) that meets the pulse shape standard.

[0050] Step 4. Perform a laser amplification operation (amplify(modulatedPulse)) on the generated modulation pulse (modulatedPulse); check whether the amplified modulation pulse meets the target pulse standard (checkUniformity(amplifiedPulse)).

[0051] If not, return to Step 3, readjust the parameters of each optical modulation switch and generate a new modulation pulse; if it meets the requirements, output the result.

[0052] Furthermore, the source pulse in this embodiment is preferably but not limited to a seed source laser pulse. According to the actual situation, it can also be other types of optical signals used for pulse shaping.

[0053] Further, each optical modulation switch of this embodiment preferably but is not limited to include an acousto-optic modulator or an electro-optic modulator, and may also be a rotating glass slide / polarizer group and other modulation switch systems, which will not be elaborated here.

[0054] With reference to Figure 5 , according to the characteristics of the AOM driven by analog signals and the AOM driven by digital signals, the AOM driven by analog signals is selected as the optical modulation switch with a longer response period, and the AOM driven by digital signals is selected as the optical modulation switch with a shorter response period.

[0055] Refer to Figure 3 , the high-frequency source pulse a passes through the optical modulation switch with a longer response period and is modulated into a pulse train b, and then passes through the optical modulation switch with a shorter response period and is secondarily modulated into a pulse train c. This pulse train c is the modulated pulse after the shaping modulation of the optical modulation switch; at this time, the pulse train c is amplified again. Since when a high-energy laser amplifies a laser pulse train, the amplification effect on the first few pulses of the laser pulse train, especially the energy of the first pulse, is always significantly higher than the energy of the subsequent stable pulses. Based on this, after the modulator in this embodiment performs more precise modulation on the two AOMs, a pulse train d with better energy consistency can be obtained. This pulse train d is the target pulse after laser amplification, solving the problem of uneven amplification of pulse energy by high-energy lasers, and having the advantages of simple operation, flexibility and high efficiency.

[0056] As another embodiment, as Figure 2 shown, the laser pulse shaping system of this embodiment includes a pulse input module 1, at least two optical modulation switches 2, a pulse output module 3, a detection and feedback module 4, and a controller 5. One end of the detection and feedback module 4 is connected to the output end of the pulse output module 3, and the other end is connected to the controller 5. The controller is connected to each optical modulation switch; the pulse input module 1 inputs a source pulse, and this source pulse passes through at least two optical modulation switches 2 for switching and modulation and then enters the pulse output module 3, and the pulse output module 3 outputs a modulated pulse; the detection and feedback module 4 is used to detect whether the modulated pulse formed after the source pulse passes through at least two optical modulation switches 2 for switching and modulation is within a preset range of the pulse shape standard. If it is within the preset range, the modulation quality is qualified; otherwise, the modulation quality is unqualified.

[0057] The controller is used to control the switching and modulation of the optical modulation switch and belongs to the command component of the system; when the modulation quality of the modulated pulse is unqualified, it is fed back to the controller, and the system reselects and adjusts the number, working time and response time of the first optical modulation switch and / or the second optical modulation switch until the modulated pulse formed by the modulation is within the preset range of the pulse shape standard, that is, a modulated pulse with the required shape standard is obtained.

[0058] The response time of an optical modulation switch often affects the number of pulses during the on and off processes. A slower response time affects a larger number of pulses, while a faster response time affects a smaller number of pulses. The working time also affects the number of selected pulses. In the fully open state, the output efficiency of the pulses is ideally 100%. During the on and off processes, only a part of the energy of the affected pulses can pass through. Therefore, the output pulse energy is the product of the transmittance of all optical modulation switches acting on them. For example, Figure 6a , Figure 6b as shown Figure 6b in the figure from left to right, the pulse energy transmittances of each pulse train are 10% * 90% = 9%, 15% * 1 = 15%, 60% * 1 = 60%, 90% * 1 = 90%, 100% * 1 = 100%, 90% * 0 = 0, 60% * 0 = 0, 15% * 0 = 0, 10% * 0 = 0; among them, Figure 6b is the modulation pulse formed after two times. The modulation pulse formed for the first time is Figure 6a , and on this basis, secondary modulation is performed to form Figure 6b .

[0059] Select the appropriate number, working time, and response time of the optical modulation switch according to the above-mentioned pulse energy transmittance.

[0060] Refer to Figure 4 , the high-frequency source pulse light A passes through two optical modulation switches α and β with different response rates, adjusts the energy growth amplitude of some pulses, and obtains pulse C. Since pulse C does not meet the preset modulation pulse after being compared and judged by the detection feedback module, it is fed back to the controller. The system selects the optical modulation switch γ. At this time, pulse C passes through the optical modulation switch γ again. By controlling the working time of the optical modulation switch γ, pulses D and E with different pulse shapes can be obtained, which can be applied to application scenarios with different pulse shape requirements.

[0061] In summary, the present invention proposes a laser pulse shaping system. This shaping system shapes the input source pulse before laser pulse amplification to obtain a modulation pulse with any target shape by controlling and adjusting the parameters of at least two optical modulation switches. It has the advantages of flexible operation, simplicity, high efficiency, etc., and meets diverse application requirements.

[0062] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

[0063] This application is described with reference to the block diagrams of computer program products according to embodiments of the present application. It should be understood that it can be implemented by computer program instructions. Instructions executed by a processor of a computer or other programmable data processing device generate for implementing the functions specified in block Figure 1 one block or multiple blocks. These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, implementing the functions specified in block Figure 1 one block or multiple blocks.

[0064] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the present application.

Claims

1. A laser pulse shaping system, characterized in that: It includes a pulse input module, at least two optical modulation switches and a pulse output module; The pulse input module inputs a source pulse, and the source pulse is switched and modulated by at least two optical modulation switches to form a modulated pulse, and the modulated pulse is output by the pulse output module; By controlling and adjusting the parameters of at least two of the optical modulation switches, the source pulse is shaped to obtain a modulated pulse that meets the pulse shape standard.

2. The laser pulse shaping system according to claim 1, characterized in that: Also includes: The detection feedback module is used to detect whether the modulated pulse formed after the source pulse is switched and modulated by at least two optical modulation switches is within a preset range of the pulse shape standard. If it is within the preset range, the modulation quality is qualified; otherwise, the modulation quality is unqualified.

3. The laser pulse shaping system according to claim 2, characterized in that: Also includes: A controller for controlling the optical modulation switch, wherein the detection feedback module is connected to the controller; When the modulation quality of the modulated pulse after modulation is unqualified, it is fed back to the controller to reselect and adjust the parameters of at least one of the optical modulation switches until the modulated pulse is within the preset range.

4. The laser pulse shaping system according to claim 1, characterized in that: The pulse shape standard is the shape of the modulated pulse required for laser amplification.

5. The laser pulse shaping system according to claim 1, characterized in that: The parameters of the optical modulation switch include the modulation switch quantity, the operating time and the response time.

6. The laser pulse shaping system according to claim 1, characterized in that: The optical modulation switch includes an acousto-optic modulator or an electro-optic modulator.

7. The laser pulse shaping system according to claim 1, characterized in that: The source pulse is a seed source laser pulse.

8. The laser pulse shaping system according to claim 1, characterized in that: The optical modulation switch includes a modulation switch driven by an analog signal or a digital signal.

9. The laser pulse shaping system according to claim 2, characterized in that: The preset range is set by reversely deducing the range of the preset modulated pulse according to the pulse shape required for laser amplification.

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