CN111338074A - Time sequence synthesis laser aberration self-adaptive correction device based on single wavefront sensor - Google Patents

Abstract

The invention discloses a timing synthesis laser aberration self-adaptive correction device based on a single wavefront sensor. The present invention takes the timing synthesis of two optical paths as an example. (2), No. 1 deformable mirror (3), No. 2 deformable mirror (4), beam combining turntable (5), wavefront sensor (6), No. 1 trigger signal source (7), No. 2 trigger signal source (8) ), a wavefront processing system (9) and a signal generator (10), wherein the wavefront sensor (6) is placed behind the beam combining turntable (5) to receive the combined beam light output by the beam combining turntable (5). The device uses a single wavefront sensor and a single wavefront processing system to correct the wavefront aberration of the multi-channel time-series composite beam, so as to improve the quality of the combined laser beam.

Description

An adaptive correction device for time-series synthesis laser aberration based on a single wavefront sensor

technical field

The invention relates to a laser aberration self-adaptive correction control device, in particular to a time-series synthesis laser aberration self-adaptive correction device based on a single wavefront sensor.

Background technique

Solid-state lasers have been widely used in important fields such as scientific research, medical treatment, and industry due to their small size, light weight, and full-point operation. Due to the influence of harmful thermal effects in the working process of solid-state lasers, how to obtain solid-state lasers with high power and high beam quality at the same time has always been a challenging problem in the industry. One of the important technical routes to solve this problem is to obtain a higher output power while maintaining the beam quality theoretically through the multi-channel laser timing synthesis method (see Li Hongmin, Zuo Junwei, Xu Jian, Xu Yiting, Peng Qinjun, Xu Zuyan). , "Research on Incoherent Synthesis of Pulsed Lasers", Laser Technology. 39, 237-241, 2015). However, in the actual laser system, the static or dynamic aberration of the combined optical path will deteriorate the quality of the sub-laser beam. Therefore, in order to ensure a better combined beam quality while combining power, the laser wavefront aberration and the combined optical path must be adjusted. Aberrations are effectively corrected.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: to solve the problem of aberration of each sub-laser beam in the sequential synthesis of pulse beams, and to provide an adaptive correction device for sequential synthesis of laser aberration based on a single wavefront sensor to improve the quality of the synthesized laser beam.

The technical scheme adopted by the present invention to solve the above problems is: a time-series synthesis laser aberration adaptive correction device based on a single wavefront sensor, the device is composed of No. 1 pulsed sub-laser, No. 2 pulsed sub-laser, No. 1 deformable mirror, 2 It consists of No. deformable mirror, beam combining turntable, wavefront sensor, No.1 trigger signal source, No.2 trigger signal source, wavefront processing system and signal generator. In the device, the wavefront sensor is connected to the input end of the wavefront processing system; the trigger signal source No. 1 corresponds to the pulse sub-laser No. 1 in the first optical path, and the trigger signal source No. 2 corresponds to the pulse sub-laser in the second optical path. The No. 2 pulsed sub-laser connects the two optical paths with the wavefront sensor and the wavefront processing system; the No. 1 deformable mirror and the No. 2 deformable mirror are arranged at the output end of the wavefront processing system to receive the control signal; the signal generator is connected through a data cable Connect with the trigger signal source No. 1 and the trigger signal source No. 2 to control the timing of the system; the pulses of the trigger signal source No. 1 and the trigger signal source No. 2 are misaligned in timing, and the wavefront sensor distinguishes the wavefront images of the two optical paths in terms of timing. When the No. 1 trigger signal source outputs a pulse trigger signal, the corresponding No. 1 pulse sub-laser outputs laser light, and the wavefront sensor detects the wavefront aberration information and sends it to the wavefront processing system. The former aberration information solves the control signal of the No. 1 deformable mirror to generate the corresponding surface shape to compensate the laser aberration; at the next moment, when the No. 2 trigger signal source outputs a pulse trigger signal, the corresponding No. 2 pulse sub-laser outputs laser light, The wavefront sensor detects the wavefront aberration information and sends it to the wavefront processing system. The wavefront processing system calculates the control signal of the No. 2 deformable mirror according to the received wavefront aberration information to generate the corresponding surface shape to compensate the laser aberration. . Through the above working mode, the self-adaptive correction device for time-series synthesis laser aberration based on a single wavefront sensor can improve the quality of the synthesized laser beam.

Wherein, when the signal generator sends out an odd-numbered pulse signal, the No. 1 trigger signal source outputs a pulse trigger signal, and the corresponding No. 1 pulse sub-laser outputs laser light.

Among them, when the signal generator sends out an even-numbered pulse signal, the No. 2 trigger signal source outputs a pulse trigger signal, and the corresponding No. 2 pulse sub-laser outputs laser light.

Among them, the No. 1 deformable mirror and the No. 2 deformable mirror are piezoelectric ceramic, magnetostrictive, electromagnetic or hydraulic drive deformable mirrors.

Wherein, the wavefront processing system may be a computer or an application-specific integrated circuit board.

In addition, an adaptive correction device for time-series synthesis laser aberration based on a single wavefront sensor is provided. The wavefront processing system determines the pulsed sub-laser currently outputting the laser according to the received pulse trigger signal, and according to the wavefront detected by the wavefront sensor The front aberration information is used to solve the control signal corresponding to the deformable mirror at this moment, so that it generates the corresponding surface shape to compensate the laser aberration. The specific implementation steps are as follows:

Step 1: When the wavefront processing system receives the pulse trigger signal from the trigger signal source No. 1, it indicates that the pulse sub-laser No. 1 outputs laser light, and the wavefront sensor detects the wavefront aberration φ _i (x, y) and sends it to the wavefront processing system System, the wavefront processing system calculates the control signal corresponding to the No. 1 deformable mirror according to the received wavefront aberration information, so that it generates the corresponding surface shape and corrects the beam wavefront aberration;

Step 2: When the wavefront processing system receives the pulse trigger signal from the No. 2 trigger signal source, it indicates that the No. 2 pulse sub-laser outputs laser light, and the wavefront sensor detects the wavefront aberration φ _j (x, y) and sends it to the wavefront processing System, the wavefront processing system calculates the control signal corresponding to the No. 2 deformable mirror according to the received wavefront aberration information, so that it generates the corresponding surface shape and corrects the beam wavefront aberration;

Step 3: Repeat steps 1 and 2.

The advantages of the present invention compared with the prior art are:

(1) The present invention aims to solve the problem of beam quality degradation caused by aberrations such as the timing synthesis optical path. Compared with the existing timing synthesis technology and pointing control technology, the beam quality after beam combination can be significantly improved;

(2) The present invention adopts the system structure of single-channel detection and time-division and branch correction, which is simpler and more compact than the existing traditional branch detection and correction structure;

(3) The present invention adopts single-channel detection and time-division to correct the aberration of the time-series synthetic laser. After the prior art time-series beam combining, the periodic time-varying high-frequency aberration existing in laser detection has very high requirements on the bandwidth of the control system, and the time-division and branching scheme of the present invention eliminates the high-frequency aberration in principle and reduces the the complexity and difficulty of control.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the present invention, wherein 1 is a pulse sub-laser No. 1, 2 is a pulse sub-laser No. 2, 3 is a deformation mirror No. 1, 4 is a deformation mirror No. 2, 5 is a beam combining turntable, and 6 is a wave Front sensor, 7 is the No. 1 trigger signal source, 8 is the No. 2 trigger signal source, 9 is the wavefront processing system, and 10 is the signal generator.

FIG. 2 is a working sequence diagram when the present invention is used for the aberration correction control of two pulsed sub-lasers time-sequential synthesis.

Fig. 3 shows the wavefront aberration before the first laser beam is corrected.

Figure 4 shows the far-field light intensity distribution before the first laser correction.

Figure 5 shows the wavefront aberration after the first laser is corrected.

Figure 6 shows the far-field light intensity distribution after the first laser correction.

Figure 7 shows the wavefront aberration before the second laser beam is corrected.

Figure 8 shows the far-field light intensity distribution before the second laser correction.

Figure 9 shows the wavefront aberration after the second laser beam is corrected.

Figure 10 shows the far-field light intensity distribution after correction by the second laser.

Figure 11 shows the far-field light intensity distribution before the combined beam laser is corrected.

Figure 12 shows the far-field light intensity distribution after correction of the combined beam laser.

Detailed ways

In order to make the working principle and implementation process of the device of the present invention clearer, the present invention is further described below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1, a time-series synthesis laser aberration adaptive correction device based on a single wavefront sensor, the device is deformed by No. 1 pulse sub-laser 1, No. 2 pulse sub-laser 2, No. 1 deforming mirror 3, No. 2 The mirror 4 , the beam combining turntable 5 , the wavefront sensor 6 , the No. 1 trigger signal source 7 , the No. 2 trigger signal source 8 , the wave front processing system 9 and the signal generator 10 are composed. In this device, the wavefront sensor 6 is connected to the input end of the wavefront processing system 9; the No. 1 trigger signal source 7 corresponds to the No. 1 pulse sub-laser 1 in the first optical path, and the No. 2 trigger signal source 8 corresponds to the No. 1 pulse sub-laser 1. The No. 2 pulsed sub-laser 2 in the two optical paths is connected to the wavefront sensor 6 and the wavefront processing system 9; Receive the control signal; the signal generator 10 is connected with the No. 1 trigger signal source 7 and the No. 2 trigger signal source through the data cable to control the system timing; the pulses of the No. 1 trigger signal source 7 and the No. 2 trigger signal source 8 are in the timing sequence The above is the dislocation phase, and the wavefront sensor 6 distinguishes the wavefront aberration information of the two optical paths from the time sequence. Among them, the No. 1 deformable mirror 3 and the No. 2 deformable mirror 4 are piezoelectric ceramic, magnetostrictive, electromagnetic or hydraulic drive deformable mirrors. The wavefront processing system 9 may be a computer or an application-specific integrated circuit board.

Set the parameters of each component in the device: the repetition frequency of the system neutron laser is set to 1000Hz, and the wavelength of the output laser beam is 671nm; the frequency of the TTL pulse signal output by the signal generator is set to 2000Hz, and the high level triggers; the TTL output of the trigger signal source The frequency of the pulse signal is set to 1000Hz, and the high level is triggered; the sampling frequency of the CCD camera in the wavefront sensor is set to 2000Hz; the deformation mirror is a piezoelectric ceramic driver deforming mirror with 59 units, and the driver adopts a hexagonal arrangement. It is set to 1000Hz; the wavefront processing system adopts a computer based on real-time Linux operating system, and the processing frequency is set to 2000Hz; the wavefront sensor adopts the Shack-Hartmann wavefront sensor, and the number of sub-apertures of the microlens is 12×12 .

The working sequence of the device of the present invention is controlled by the signal generator 10 . FIG. 2 is a timing chart showing the operation of various components in the device under the regulation of the output pulse of the signal generator 10 . In the figure, each component is represented by 1 when it is working, and it is represented by 0 when it is not working.

When the signal generator 10 sends out the 1st, 3rd, 5th, 7th ... pulse signals, the pulse trigger signal output by the trigger signal source 7 of No. 1 is at a rising edge or a high level, and the corresponding pulse sub-laser 1 of No. 1 outputs laser light. . The wavefront sensor 6 detects the wavefront aberration information and sends it to the wavefront processing system 9. The wavefront processing system 9 calculates the control signal of the No. 1 deformable mirror 3 according to the received wavefront aberration information to generate the corresponding surface shape Compensates for laser aberrations.

When the signal generator 10 sends out the 2nd, 4th, 6th, 8th pulse signal, the pulse trigger signal output by the No. 2 trigger signal source 8 is at a rising edge or a high level, and the corresponding No. 2 pulse sub-laser 2 outputs laser light. . The wavefront sensor 6 detects the wavefront aberration information and sends it to the wavefront processing system 9. The wavefront processing system 9 calculates the control signal of the No. 2 deformable mirror 4 according to the received wavefront aberration information to generate the corresponding surface shape Compensates for laser aberrations.

The wavefront processing system 9 determines the pulsed sub-laser currently outputting the laser according to the received pulse trigger signal, and calculates the control signal corresponding to the deformable mirror at this moment according to the wavefront aberration information detected by the wavefront sensor 6, so as to generate the corresponding control signal. The surface shape compensates laser aberration, and the specific implementation steps are as follows:

When the wavefront processing system 9 receives the pulse trigger signal from the No. 1 trigger signal source 7, it indicates that the No. 1 pulse sub-laser 1 outputs laser light, and the wavefront sensor 6 detects the wavefront aberration φ _i (x, y) and sends it to the wavefront The processing system 9, the wavefront processing system 9 calculates the control signal corresponding to the No. 1 deformable mirror 3 according to the received wavefront aberration information, so that it generates a corresponding surface shape and corrects the wavefront aberration of the beam;

Step 2: When the wavefront processing system 9 receives the pulse trigger signal from the No. 2 trigger signal source 8, it indicates that the No. 2 pulse sub-laser 2 outputs laser light, and the wavefront sensor 6 detects the wavefront aberration φ _j (x, y) and sends To the wavefront processing system 9, the wavefront processing system 9 calculates the control signal corresponding to the No. 2 deformable mirror 4 according to the received wavefront aberration information, so that it generates a corresponding surface shape and corrects the wavefront aberration of the beam;

Step 3: Repeat steps 1 and 2.

Fig. 3-Fig. 12 are the simulation results of the typical wavefront aberration correction of the laser, and Fig. 3 is the first-path laser to correct the front wavefront aberration. Figure 4 shows the far-field light intensity distribution before the first laser correction. Figure 5 shows the wavefront aberration after the first laser is corrected. Figure 6 shows the far-field light intensity distribution after the first laser correction. Figure 7 shows the wavefront aberration before the second laser beam is corrected. Figure 8 shows the far-field light intensity distribution before the second laser correction. Figure 9 shows the wavefront aberration after the second laser beam is corrected. Figure 10 shows the far-field light intensity distribution after correction by the second laser. Figure 11 shows the far-field light intensity distribution before the combined beam laser is corrected. Figure 12 shows the far-field light intensity distribution after correction of the combined beam laser. Among them, the effect of correction is related to the number of units of the deformed mirror selected. Taking the β factor as the beam quality evaluation index, the beam quality of the first channel of laser before correction is β ₁ =10.92, the beam quality after correction is β′ ₁ =2.45; the beam quality of the second channel of laser before correction is β ₂ =11.24 , the corrected beam quality is β′ ₂ =2.58; the beam quality before the correction of the combined beam laser is β _c =13.26, and the corrected beam quality is β′ _c =2.71. It can be seen that, after correction, the beam quality after the beam combination is improved by nearly 5 times.

Claims (6)

1. A time-series synthesis laser aberration self-adaptive correction device based on a single-wavefront sensor, characterized in that: the device consists of No. 1 pulse sub-laser (1), No. 2 pulse sub-laser (2), No. 1 deformable mirror ( 3), No. 2 deformable mirror (4), beam combining turntable (5), wavefront sensor (6), No. 1 trigger signal source (7), No. 2 trigger signal source (8), wavefront processing system (9) and a signal generator (10), in the device, the wavefront sensor (6) is connected to the input end of the wavefront processing system (9); the No. 1 trigger signal source (7) corresponds to the first optical path No. 2 pulsed sub-laser (1), and No. 2 trigger signal source (8) corresponds to No. 2 pulsed sub-laser (2) in the second optical path, and the two parts of the optical path are connected with the wavefront sensor (6) and the wavefront processing system (9) connected; No. 1 deformable mirror (3) and No. 2 deformable mirror (4) are arranged at the output end of the wavefront processing system (9) to receive the control signal; the signal generator (10) is connected to the No. 1 trigger signal through a data cable The source (7) and the No. 2 trigger signal source (8) are connected to control the system timing; the pulses of the No. 1 trigger signal source (7) and the No. 2 trigger signal source (8) are misaligned in timing, and the wavefront sensor (6) ) Distinguish the wavefront aberration information of the two optical paths in terms of time sequence; when the No. 1 trigger signal source (7) outputs a pulse trigger signal, the corresponding No. 1 pulse sub-laser (1) outputs laser light, and the wavefront sensor (6) detects the wavefront image The difference information is sent to the wavefront processing system (9), and the wavefront processing system (9) calculates the control signal of the No. 1 deformable mirror (3) according to the received wavefront aberration information to generate the corresponding surface shape compensation laser aberration; at the next moment, when the No. 2 trigger signal source (8) outputs a pulse trigger signal, the corresponding No. 2 pulse sub-laser (2) outputs laser light, and the wavefront sensor (6) detects the wavefront aberration information and sends it to the wavefront A preprocessing system (9), the wavefront processing system (9) calculates the control signal of the No. 2 deformable mirror (4) according to the received wavefront aberration information to generate a corresponding surface shape to compensate the laser aberration; through the above work The laser aberration self-adaptive correction device based on the time-series synthesis of the single wavefront sensor can improve the quality of the synthesized laser beam. 2. A kind of time-series synthesis laser aberration self-adaptive correction device based on single-wavefront sensor as claimed in claim 1, is characterized in that: when the signal generator (10) sends out the odd-numbered pulse signal, No. 1 triggers the signal source (7) Output a pulse trigger signal, and the corresponding No. 1 pulse sub-laser (1) outputs laser light. 3. a kind of time-series synthesis laser aberration self-adaptive correction device based on single-wavefront sensor as claimed in claim 1 is characterized in that: when the signal generator (10) sends out the even-numbered pulse signal, No. 2 triggers the signal source (8) Output a pulse trigger signal, and the corresponding No. 2 pulse sub-laser (2) outputs laser light. 4. The device for self-adaptive correction of time-series synthesis laser aberration based on a single-wavefront sensor according to claim 1, characterized in that: the No. 1 deformable mirror (3) and the No. 2 deformable mirror (4) are piezoelectric ceramics , Magnetostrictive, Electromagnetic or Hydraulic Drive Deformable Mirrors. 5. The device for self-adapting laser aberration correction based on a single-wavefront sensor according to claim 1, wherein the wavefront processing system (9) can be a computer or an application-specific integrated circuit board. 6. A time-series synthesis laser aberration adaptive correction device based on a single wavefront sensor as claimed in claim 1, wherein the wavefront processing system (9) judges the current output laser according to the received pulse trigger signal. The pulsed sub-laser is used to calculate the control signal of the corresponding deformable mirror at this moment according to the wavefront aberration information detected by the wavefront sensor (6), so as to generate the corresponding surface shape to compensate the laser aberration. The specific implementation steps are as follows: Step 1: When the wavefront processing system (9) receives the pulse trigger signal from the No. 1 trigger signal source (7), it indicates that the No. 1 pulse sub-laser (1) outputs laser light, and the wavefront sensor (6) detects the wavefront aberration φ _i (x, y) is sent to the wavefront processing system (9), and the wavefront processing system (9) calculates the control signal corresponding to the No. 1 deformable mirror (3) according to the received wavefront aberration information, and makes it generate Corresponding surface shape, correct beam wavefront aberration; Step 2: When the wavefront processing system (9) receives the pulse trigger signal from the No. 2 trigger signal source (8), it indicates that the No. 2 pulse sub-laser (2) outputs laser light, and the wavefront sensor (6) detects the wavefront aberration φ _j (x, y) is sent to the wavefront processing system (9), and the wavefront processing system (9) calculates the control signal corresponding to the No. 2 deformable mirror (4) according to the received wavefront aberration information, and makes it generate Corresponding surface shape, correct beam wavefront aberration; Step 3: Repeat steps 1 and 2.

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