Method for measuring delay between high-power laser beams

Abstract

A high-power laser beam time delay measuring device is characterized in that a signal sent by a clock reference is accessed to a first channel of a high-speed oscilloscope in an electric signal mode during relative time delay measurement of a fundamental frequency band, and a pulse output by a repetition frequency main laser system is received by a first photoelectric tube, converted into an electric pulse and accessed to a second channel of the high-speed oscilloscope; during triple frequency band relative time delay measurement, triple frequency simulation light is received by the second phototube after penetrating through the terminal optical element and is converted into an electric pulse, and the electric pulse is accessed to a third channel of the high-speed oscilloscope. According to the invention, time delay measurement is carried out through segmentation and wavelength division, and finally total delay accumulation is carried out to determine the time delay of each path of light beam reaching a target point relative to a reference. The high-precision measurement of the inter-beam delay can be realized without adding equipment by utilizing the existing equipment such as a repetition frequency main laser system and a frequency tripling simulation light source, the principle and the structure are simple, the cost is low, and the engineering realization is easy.

Description

Technical Field

[0001] The invention belongs to the field of laser technology, and in particular to a device and method for measuring the time delay between high-power laser beams. The invention relates to time delay measurement and adjustment of a multi-beam high-power laser system. Background Art

[0002] In the field of high-power laser technology, when multiple beams are needed for target shooting in physical experiments, it is usually required that multiple laser beams reach the target at the same time. Since the time interval between high-power laser high-energy emission is generally several hours and the emission cost is relatively high, in order to improve the efficiency of precise adjustment of multi-channel laser time synchronization and save costs, it is generally not necessary to precisely measure the delay between beams by emitting high-energy laser beams. The usual practice is to use other methods such as small-energy indirect methods to precisely measure and adjust the delay between laser beams, and if necessary, emit high-energy shots to confirm and further eliminate errors. If the accuracy of the small-energy indirect method of precisely measuring and adjusting the delay between beams can achieve a higher accuracy and have a higher implementation efficiency, the high-energy shots can be eliminated and the accuracy of beam synchronization can be guaranteed.

[0003] High-power laser systems generally use large-aperture neodymium glass materials as amplification media, and the central wavelength of the output laser is generally 1053nm, which is called fundamental frequency light. In order to improve the beam-target coupling efficiency, large-aperture nonlinear crystals are generally used as harmonic conversion modules to perform harmonic conversion on the fundamental frequency beam, converting the frequency of the beam from the fundamental frequency to the doubled frequency or tripled frequency. Nonlinear crystals are optimized and designed according to the power density characteristics of the fundamental frequency output of high-power laser devices, and the harmonic conversion efficiency is closely related to the power density characteristics. When emitting high energy, the harmonic conversion efficiency can generally exceed 60%. However, the laser power density used for debugging is generally more than 3 orders of magnitude lower than that of high energy emission. The tripled frequency energy generated after nonlinear crystal conversion is generally more than 9 orders of magnitude lower. If the fundamental frequency beam without harmonic conversion enters the target sphere, it will form objective noise on the detection surface, rising to several orders of magnitude higher than the tripled frequency signal, which will seriously interfere with the time waveform measurement results of each beam. Summary of the invention

[0004] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to propose a device and method for measuring the delay between high-power laser beams, which performs time delay measurement by segmented and divided wavelengths, and finally accumulates the total delay to determine the time delay of each light beam relative to a reference.

[0005] To achieve the above objectives, the technical solutions of the present invention are as follows:

[0006] A high-power laser beam delay measurement device and method, characterized in that the device includes a clock reference, a high-speed oscilloscope, a first photoelectric tube, a second photoelectric tube, a repetition frequency main laser system and a triple frequency simulation light. When the time delay measurement is performed in segments and wavelengths, it is completed in two stages: relative time delay measurement of the base frequency band and relative delay measurement of the triple frequency band.

[0007] When measuring the relative time delay in the baseband, the signal sent by the clock reference is finally connected to the first channel of the high-speed oscilloscope in the form of an electrical signal as a reference point for the baseband time delay. The output pulse of the repetitive main laser system is received by the first photoelectric tube before reaching the harmonic conversion module through the high-power laser system. The electrical pulse generated by the first photoelectric tube is connected to the second channel of the high-speed oscilloscope. The first channel or the second channel of the oscilloscope is selected as the external trigger source of the oscilloscope. The delay of the waveform of the first channel of the oscilloscope and the waveform of the second channel of the oscilloscope after the trigger is recorded once is recorded as Δt1.

[0008] When measuring the relative time delay in the triple frequency band, the triple frequency simulation light is incident from the front of the harmonic conversion module, and converges to the target point after passing through the harmonic conversion module and other terminal optical components. A second photoelectric tube is placed at the target point, and the electric pulse generated by the second photoelectric tube is connected to the third channel of the high-speed oscilloscope. The second channel or the third channel of the oscilloscope is selected as the external trigger source of the oscilloscope, and the delay of the waveform of the second channel of the oscilloscope and the waveform of the third channel of the oscilloscope after the trigger is recorded, which is recorded as Δt2.

[0009] Finally, the total delay is accumulated to determine that the time delay of each main laser beam reaching the target relative to the reference is Δ=Δt1+Δt2+δ, where δ is a fixed deviation, which is related to the first phototube, the second phototube, and the cable connecting them to the oscilloscope. For multiple laser beams, the same first phototube, the second phototube, and the cable connecting them to the oscilloscope are used. By repeating the above steps, the time delay of each light beam reaching the target relative to the clock reference can be measured respectively.

[0010] The first photoelectric tube must respond to both the fundamental frequency beam and the triple frequency beam.

[0011] The delay amount of the output pulse of the repetition-rate master laser system relative to the clock reference does not change with time.

[0012] The tripled frequency simulation light is coaxial with the tripled frequency light beam generated by the main laser.

[0013] The triple frequency simulation light is generally based on a Q-switched laser for intracavity or extracavity harmonic conversion to generate a repetition rate pulse laser of several thousand Hz, and generally there will be many small peaks at equal intervals.

[0014] The position and posture of the first photoelectric tube remain unchanged when performing relative time delay measurement in the base frequency band and relative time delay measurement in the triple frequency band.

[0015] Compared with the prior art, the technical effects of the present invention are as follows:

[0016] The time delay is measured by segmenting and wavelength division, and finally the total delay is accumulated to determine the time delay of each main laser beam reaching the target relative to the reference.

[0017] By utilizing the existing repetition rate main laser system, triple frequency analog light source and other equipment, high-precision measurement of inter-beam delay can be achieved without adding new equipment. The principle and structure are simple, the cost is low, and it is easy to implement in engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the high-power laser beam delay measurement device of the present invention, wherein a is a schematic diagram of the relative time delay measurement of the base frequency band, and b is a schematic diagram of the relative time delay measurement of the triple frequency band.

[0019] In the figure: 1-clock reference; 2-high-speed oscilloscope; 201-first channel of high-speed oscilloscope; 202-second channel of high-speed oscilloscope; 203-third channel of high-speed oscilloscope; 3-first phototube; 4-second phototube; 5-repetition main laser system; 6-tripled frequency simulation light; 7-harmonic conversion module; 8-main laser before the harmonic conversion module; 9-light beam after the harmonic conversion module; 10-tripled frequency simulation light before the harmonic conversion module; 11-tripled frequency simulation light after the harmonic conversion module.

[0020] Figure 2 This is a schematic diagram of the relative time delay measurement in the baseband.

[0021] In the figure: 2011- schematic diagram of the clock reference waveform of the first channel of the high-speed oscilloscope; 2021- schematic diagram of the time waveform of the first phototube recorded by the second channel of the high-speed oscilloscope and the relative time delay during baseband time measurement.

[0022] Figure 3 This is a schematic diagram of the relative time delay measurement in the triple frequency band.

[0023] In the figure: 2022- three times the frequency band time measurement, the second channel of the high-speed oscilloscope records the time waveform of the first phototube and the relative time delay; 2032- three times the frequency band time measurement, the first phototube records the time waveform and the relative time delay. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with embodiments and drawings, but the protection scope of the present invention shall not be limited thereto.

[0025] Example:

[0026] Figure 1 The present invention is a schematic diagram of a high-power laser beam delay measurement device, which includes a clock reference 1, a high-speed oscilloscope 2, a first phototube 3, a second phototube 4, a repetition frequency main laser system 5 and a triple frequency simulation light 6. When the time delay measurement is performed in segments and wavelengths, it is completed in two stages: relative time delay measurement of the base frequency band and relative delay measurement of the triple frequency band.

[0027] When measuring the relative time delay in the baseband, the signal emitted by the clock reference 1 is finally connected to the first channel 201 of the high-speed oscilloscope 2 in the form of an electrical signal as a reference point for the baseband time delay. The output pulse of the repetition master laser system 5 is received by the first photoelectric tube 3 before reaching the harmonic conversion module 7 through the high-power laser system. The electrical pulse generated by the first photoelectric tube is connected to the second channel 202 of the high-speed oscilloscope. The first channel 201 of the oscilloscope or the second channel 202 of the oscilloscope is selected as the external trigger source of the oscilloscope, and the delay amount of the waveform 2011 of the first channel 201 of the oscilloscope and the waveform 2021 of the second channel 202 of the oscilloscope after one trigger is recorded, and recorded as Δt1.

[0028] When measuring the relative time delay in the triple frequency band, the triple frequency simulation light 6 is incident from the front of the harmonic conversion module 7, and converges to the target point after passing through the terminal optical components such as the harmonic conversion module 7, and the second photoelectric tube 4 is placed at the target point, and the electric pulse generated by the second photoelectric tube 4 is connected to the third channel 203 of the high-speed oscilloscope. The second channel 202 of the oscilloscope or the third channel 203 of the oscilloscope is selected as the external trigger source of the oscilloscope, and the delay amount of the waveform 2022 of the second channel 202 of the oscilloscope and the waveform 2032 of the third channel 203 of the oscilloscope after one trigger is recorded, and recorded as Δt2.

[0029] Finally, the total delay is accumulated to determine that the time delay of each light beam output by the repetition main laser system 5 to reach the target relative to the clock reference 1 is Δ=Δt1+Δt2+δ, where δ is a fixed deviation, which is related to the first phototube 3, the second phototube 4 and the cable connecting them to the oscilloscope. For multiple laser beams, the same first phototube 3, the second phototube 4 and the cable connecting them to the oscilloscope are used. By repeating the above steps, the time delay of each light beam reaching the target relative to the clock reference can be measured respectively.

[0030] The first photoelectric tube 3 must respond to both the fundamental frequency light beam and the triple frequency light beam.

[0031] The delay amount of the output pulse of the repetition-rate master laser system relative to the clock reference 1 does not change with time.

[0032] The tripled frequency simulation light 6 is coaxial with the tripled frequency light beam generated by the main laser.

[0033] The triple frequency simulation light 6 is generally based on a Q-switched laser for intracavity or extracavity harmonic conversion to generate a repetition rate pulse laser of several thousand Hz, and generally there will be many small peaks at equal intervals.

[0034] The position and posture of the first photoelectric tube 3 remain unchanged when performing relative time delay measurement in the base frequency band and relative time delay measurement in the triple frequency band.

[0035] The device includes a clock reference, a high-speed oscilloscope, a first photoelectric tube, a second photoelectric tube, a repetition frequency main laser system and a triple frequency simulation light. When the time delay measurement is performed in segments and wavelengths, it is completed in two stages: relative time delay measurement of the base frequency band and relative delay measurement of the triple frequency band.

[0036] When measuring the relative time delay in the baseband, the signal sent by the clock reference is finally connected to the first channel of the high-speed oscilloscope in the form of an electrical signal as a reference point for the baseband time delay. The output pulse of the repetitive main laser system is received by the first photoelectric tube before reaching the harmonic conversion module through the high-power laser system. The electrical pulse generated by the first photoelectric tube is connected to the second channel of the high-speed oscilloscope. The first channel or the second channel of the oscilloscope is selected as the external trigger source of the oscilloscope. The delay of the waveform of the first channel of the oscilloscope and the waveform of the second channel of the oscilloscope after the trigger is recorded once is recorded as Δt1.

[0037] When measuring the relative time delay in the triple frequency band, the triple frequency simulation light is incident from the front of the harmonic conversion module, and converges to the target point after passing through the harmonic conversion module and other terminal optical components. A second photoelectric tube is placed at the target point, and the electric pulse generated by the second photoelectric tube is connected to the third channel of the high-speed oscilloscope. The second channel or the third channel of the oscilloscope is selected as the external trigger source of the oscilloscope, and the delay of the waveform of the second channel of the oscilloscope and the waveform of the third channel of the oscilloscope after the trigger is recorded, which is recorded as Δt2.

[0038] Finally, the total delay is accumulated to determine that the time delay of each light beam output by the repetition main laser system to reach the target relative to the reference is Δ=Δt1+Δt2+δ, where δ is a fixed deviation, which is related to the first phototube, the second phototube and the cable connecting them to the oscilloscope. For multiple laser beams, the same first phototube, the second phototube and the cable connecting them to the oscilloscope are used. By repeating the above steps, the time delay of each light beam reaching the target relative to the clock reference can be measured respectively.

[0039] The first photoelectric tube must respond to both the fundamental frequency beam and the triple frequency beam.

[0040] The delay amount of the output pulse of the repetition-rate master laser system relative to the clock reference does not change with time.

[0041] The tripled frequency simulation light is coaxial with the tripled frequency light beam generated by the main laser.

[0042] The triple frequency simulation light is generally based on a Q-switched laser for intracavity or extracavity harmonic conversion to generate a repetition rate pulse laser of several thousand Hz, and generally there will be many small peaks at equal intervals.

[0043] The position and posture of the first photoelectric tube remain unchanged when performing relative time delay measurement in the base frequency band and relative time delay measurement in the triple frequency band.

[0044] In actual operation, it is often not necessary to pay attention to the absolute value of the delay of a certain beam reaching the target relative to the clock reference. It is only necessary to ensure that the time when multiple beams reach the target is consistent, or to adjust the delay relative to a certain beam. In this case, the fixed deviation δ related to factors such as the first phototube, the second phototube, and the cable connecting them to the oscilloscope can be ignored because the delay measurement for each beam is the same, and only the sum of Δt1 and Δt2 needs to be paid attention to.

[0045] If you need to pay attention to the absolute value of the delay of a certain beam reaching the target relative to the clock reference, the fixed deviation δ related to factors such as the first phototube, the second phototube, and the cables connecting them to the oscilloscope cannot be ignored. You can calibrate the absolute deviation in advance and deduct it when calculating the absolute delay.

[0046] When a high-power laser device requires multiple beams to reach the target at the same time, it is usually necessary to precisely control the time when each beam reaches the target. A high-power laser system is generally equipped with a precise timing system, which is distributed to each functional module for use so that the entire system can work together. The present invention does not require the addition of additional devices or the emission of high-energy laser energy. Through the above operation process, the precise measurement of the time when each laser beam reaches the target relative to the reference clock reference delay can be achieved.

Claims

1. A high-power laser beam delay measurement device, characterized in that: It includes a clock reference, a high-speed oscilloscope, a first phototube, a second phototube, a repetition frequency main laser system and a triple frequency simulation light; wherein, When measuring the relative time delay in the baseband, the signal emitted by the clock reference is connected to the first channel of the high-speed oscilloscope in the form of an electrical signal, and the pulse output by the repetition frequency main laser system is received by the first photoelectric tube and converted into an electrical pulse, which is connected to the second channel of the high-speed oscilloscope; When measuring the relative time delay in the triple frequency band, the triple frequency analog light is received by the second photoelectric tube after passing through the terminal optical element and converted into an electrical pulse, which is then connected to the third channel of the high-speed oscilloscope.

2. The high-power laser beam delay measurement device according to claim 1, characterized in that: The first photoelectric tube responds to both the fundamental frequency light beam and the triple frequency light, and its position and posture remain unchanged when performing relative time delay measurement of the fundamental frequency band and the triple frequency band.

3. The high-power laser beam delay measurement device according to claim 1, characterized in that: By selecting different channels of the high-speed oscilloscope as trigger sources, the waveform delays Δt1 and Δt2 of the baseband and triple frequency band are recorded respectively, and the total delay Δ=Δt1+Δt2+δ is determined, where δ is a fixed deviation.

4. The high-power laser beam delay measurement device according to claim 1, characterized in that: The tripled frequency simulation light is coaxial with the tripled frequency light beam generated by the main laser.

5. The high-power laser beam delay measurement device according to claim 1 or 4, characterized in that: The triple frequency simulation light is a repetitive frequency pulse laser generated by harmonic conversion of a Q-switched laser, and has small peaks at equal intervals.

6. The high-power laser beam delay measurement device according to any one of claims 1 to 5, characterized in that: When the first photoelectric tube performs relative time delay measurement in the base frequency band and relative time delay measurement in the triple frequency band, the position and posture of the first photoelectric tube remain unchanged.

7. A method for measuring the delay between high-power laser beams, characterized in that: It includes two stages: baseband relative time delay measurement and triple frequency band relative delay measurement; Baseband relative time delay measurement phase: The signal emitted by the clock reference (1) is connected to the first channel (201) of the high-speed oscilloscope (2) in the form of an electrical signal as a reference point for the fundamental frequency time delay; The main laser output by the repetition main laser system (5) is received by the first photoelectric tube (3), and the electric pulse generated by the first photoelectric tube (3) is connected to the second channel (202) of the high-speed oscilloscope (2); The first channel (201) or the second channel (202) of the high-speed oscilloscope (2) is selected as an external trigger source, and the delay between the waveform (2011) of the first channel (201) and the waveform (2021) of the second channel (202) after one trigger is recorded as Δt 1； Three-fold frequency band relative delay measurement stage: The tripled frequency simulated light output by the tripled frequency simulated light (6) is transmitted through the harmonic conversion module (7) and then converged to the target point, and is received by the second photoelectric tube (4) located at the target point. The electric pulse generated by the second photoelectric tube (4) is connected to the third channel (203) of the high-speed oscilloscope; Selecting the second channel (202) or the third channel (203) of the high-speed oscilloscope as an external trigger source, and recording the delay of the waveform (2022) of the second channel (202) and the waveform (2032) of the third channel (203) after one trigger, and recording it as Δt2; Calculate the time delay Δ of the time when the main laser reaches the target relative to the clock reference (1) using the following formula: Δ=Δt1+Δt2+δ Wherein, δ is a fixed deviation, which is related to the first photoelectric tube (3), the second photoelectric tube (4) and the cables connecting them to the high-speed oscilloscope (2).

8. The method for measuring the delay between high-power laser beams according to claim 7, characterized in that: For multiple laser beams, repeat the above steps to measure the delay of each beam reaching the target relative to the clock reference.

9. The method for measuring the delay between high-power laser beams according to claim 7, characterized in that: The delay amount of the output pulse of the repetition-rate master laser system relative to the clock reference (1) does not change with time.

10. The method for measuring the delay between high-power laser beams according to claim 7, characterized in that: During measurement, the triple frequency simulation light (6) is coaxial with the triple frequency light beam generated by the main laser.

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