Six-pass amplified high-power laser device crystal near-field center position deviation detection system

Abstract

This invention relates to a crystal near-field center position deviation detection system for a six-pass amplified high-power laser device, belonging to the field of high-power laser device collimation technology. The near-field position of the crystal is determined using a pair of pyramids, and the near-field center of the main beam is determined using two pairs of small beams that coincide in the near field and separate in the far field, serving as the near-field reference for the main beam. A near-field camera simultaneously receives the light spots of the near-field reference small beam pair and the reflected light spots from the pyramids; the center deviation of the two pairs of spots is the deviation of the crystal's near-field center position relative to the main beam. Based on the deviation value, a feedback control system automatically adjusts the crystal's near-field position for collimation. This invention solves the problem of low image resolution and difficulty in centering and precise adjustment during crystal collimation, which requires human observation of the crystal's near-field position and the deviation of the main beam. This invention improves crystal collimation efficiency and adjustment accuracy, and features simple equipment, easy adjustment, and high precision.

Description

Technical Field

[0001] This invention belongs to the field of high-power laser device collimation technology, and in particular, it is a crystal near-field center position deviation detection system for a six-pass amplified high-power laser device. Background Technology

[0002] In the existing field of inertial confinement fusion research both domestically and internationally, high-power laser devices play a crucial role. These devices all rely on the precise near-field collimation of frequency-doubling crystals to achieve optimal performance. However, current mainstream collimation adjustment techniques still rely on manual operation. Specifically, the operator observes the image of the laser beam at the crystal position with the naked eye and manually adjusts a pair of mirrors located in front of the crystal to align the crystal center with the center of the main laser beam.

[0003] However, this method is limited by the low resolution of human vision, making it difficult to accurately capture the center position of the crystal, thus affecting the precision and efficiency of the adjustment. Therefore, this technical bottleneck not only increases the operational difficulty but also restricts the realization of the potential of high-power laser devices in inertial confinement fusion applications.

[0004] Therefore, there is an urgent need for a more efficient and precise collimation adjustment scheme to overcome the limitations of existing technologies and promote the further development of related technologies. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a crystal near-field center position deviation detection system for a six-pass amplified high-power laser device. By placing a near-field reference beam and a cone, the near-field center of the main beam and the crystal center are respectively located. The near-field center position deviation of the crystal is automatically detected, and the crystal is adjusted to collimation based on the deviation value using a feedback system. This device is characterized by simple equipment, easy adjustment, and high precision.

[0006] The technical solution of the present invention is as follows:

[0007] A near-field center position deviation detection system for a six-pass amplified high-power laser device crystal, characterized in that it includes:

[0008] Two pairs of small beams are placed behind the first adjusting mirror RM1 to provide near-field reference. The near-field positions of the two pairs of small beams coincide, but their far-field angles are different. The far-field pointing of the beam pairs passes through different filter apertures of the transmission space filter.

[0009] A pair of pyramids, which can be moved in and out of the crystal, are placed in front of the crystal to calibrate the near-field position of the crystal;

[0010] The second adjusting mirror TM3 and the third adjusting mirror TM4 are positioned in front of the cone to adjust the beam path of the incident crystal.

[0011] A right-angle prism, movable to different filter apertures of the transmission space filter, is used to reflect the beam to the near-field detection system;

[0012] A near-field detection system is used to acquire and image near-field images of the main beam and reflected light spots from small beams and cones;

[0013] The following steps are used to detect and adjust the near-field center position deviation of the crystal:

[0014] a) By adjusting the near-field center of the main beam to coincide with the near-field center of the small beam pair after passing through different filtering apertures of the transmission space filter, the near-field reference of the main beam is determined; b) Using another small beam pair as a near-field position reference, the beam is reflected to the near-field detection system for imaging after moving a right-angle prism to the corresponding filtering aperture; c) A pair of pyramids are moved into the main optical path and placed symmetrically in front of the crystal relative to the crystal centerline, reflecting the main laser to the near-field detection system for imaging, thus obtaining the center of the pyramidal reflected spot; d) The deviation between the center of the near-field reference small beam pair and the center of the pyramidal reflected spot is compared, and the deviation is adjusted to within the predetermined error range by adjusting the reflecting mirror group TM3 and TM4, thereby achieving collimation of the near-field position of the crystal.

[0015] Furthermore, it also includes a feedback system for adjusting the second adjustment mirror TM3 and the third adjustment mirror TM4 based on the deviation between the center of the reflected light spot of the pyramid pair in the near-field camera and the center of the light spot of the near-field reference small beam pair, so that the deviation of the center position of the two pairs of light spots is adjusted to the error range.

[0016] Preferably, the near-field detection system comprises a beam-shrinking lens, an imaging mirror, a first imaging lens, a second imaging lens, and a near-field detection camera arranged sequentially along the optical path. The beam is imaged onto the near-field detection camera (35) through the beam-shrinking lens (31), the imaging mirror (32), the first imaging lens (33), and the second imaging lens (34) to obtain the near-field image center of the main beam and the imaging spot of the small beam.

[0017] Furthermore, the optical path system of the six-pass amplified high-power laser device, after output from the preamplifier and along the laser transmission direction, sequentially includes a first injection mirror In-M1, a second injection mirror In-M2, a third injection mirror In-M3, an injection lens, a first mirror P0, a first and fourth aperture of the transmission space filter (TSF), a transmission space filter focusing lens TSF-L1, a first amplifying medium, a first adjusting mirror RM1, a cavity mirror CM1, a second mirror P1, a polarization converter PEPC, a cavity space filter (CSF) lens CSF-L1, four cavity space filter apertures, a cavity space filter lens CSF-L2, a second amplifying medium, and a cavity mirror CM2. After double-pass amplification by the first amplifying medium and four-pass amplification by the second amplifying medium, the light is reflected by the third mirror TM1, the fourth mirror TM2, the second adjusting mirror TM3, and the third adjusting mirror TM4 to the terminal optical system where the crystal is located.

[0018] The specific method for detecting near-field center deviation of a crystal using the above system includes the following steps:

[0019] Step 1. Place two pairs of small beams behind the first adjustment mirror RM1. The near-field positions of these two pairs of small beams coincide, while the far-field angles are different. The far-field pointing of the beam pairs passes through the first and fourth apertures of the transmission space filter, respectively. Therefore, we distinguish them by calling them the small beam pair passing through the first aperture and the small beam pair passing through the fourth aperture.

[0020] Step 2. Determine the near-field reference of the main beam. Use the small beam pair passing through the fourth aperture to adjust the near-field center of the main beam and the near-field center of the small beam pair to coincide. The near-field reference position of the main beam is calibrated by the small beam pair passing through the fourth aperture placed behind the first adjustment mirror RM1.

[0021] The optical path of the main beam of the six-pass amplified high-power laser device is shown in the figure. The main beam from the preamplifier is injected into the first aperture of the transmission space filter through the injection mirror. After passing through the transmission space filter lens TSF-L1, it becomes a parallel beam. After passing through the first amplification medium, it is reflected by the first adjustment mirror RM1 and the second mirror P1, and then enters the cavity space filter. After four passes of amplification, it is focused by the cavity space filter focusing lens CSF-L1, passes through the first aperture of the cavity space filter, becomes parallel after passing through CSF-L2, is amplified by the second amplification medium, is reflected by the cavity mirror CM2, and then passes sequentially through the second amplification medium, the cavity converging lens CSF L2, the second aperture of the cavity space filter, the cavity converging lens CSF-L1, and the polarization converter PEPC. Then the beam passes sequentially through the cavity mirror CM1, PEPC, and after PEPC is turned off, it passes sequentially through CSF-L1, the third aperture of the cavity space filter, CSF-L2, the second amplification medium, CM2, the second amplification medium, CSF-L2, the fourth aperture of the cavity space filter, and CSF-L1. After being amplified through these four stages, the light is reflected by the second mirror P1, then through RM1, the first amplifying medium, TSF-L1, the fourth aperture of the transmission space filter, the transmission space filter lens TSF-L2, and finally reflected by the third mirror TM1, the fourth mirror TM2, the second adjusting mirror TM3, and the third adjusting mirror TM4 before being output to the terminal optical system where the crystal is located.

[0022] After the right-angle prism is moved to the fourth aperture of the TSF filter, the small beam pair placed behind the first adjusting mirror RM1 passes through the fourth aperture together with the main beam after four passes of amplification. They then pass through the first amplification medium, TSF-L1, and the fourth aperture of the transmission space filter. After being reflected by the right-angle prism, they are sent to the near-field detection system. The beams are then imaged by the beam-shrinking lens, the imaging mirror, the first imaging lens, and the second imaging lens to the near-field detection camera. The near-field image center of the main beam and the imaging spot of the small beam are obtained. The injection mirror in front of the amplification system is adjusted so that the near-field image center of the main beam coincides with the center of the spot of the small beam pair passing through the fourth aperture. Thus, the center of the small beam pair passing through the fourth aperture is used as the near-field reference of the main beam.

[0023] Step 3. The near-field positions of the small beam pair passing through the first aperture and the small beam pair passing through the fourth aperture coincide. Therefore, the near-field center of the small beam pair passing through the first aperture also coincides with the near-field center of the main beam. Thus, the center of the small beam pair passing through the first aperture is also used as the near-field reference of the main beam.

[0024] Step 4. After moving the right-angle prism to the first aperture of the TSF filter, the small beam pair passing through the first aperture passes through the first amplifying medium, TSF-L1, and the first aperture, and is reflected by the right-angle prism to the near-field detection system. After passing through the beam-shrinking lens, imaging mirror, first imaging lens, and second imaging lens, it is received by the near-field detection camera and imaged as a pair of small light spots. The center of the small light spot pair represents the reference center of the near-field beam position. The small beam pair passing through the first aperture serves as the near-field reference small beam of the main beam for subsequent detection and adjustment.

[0025] Step 5. At the other end, the position of the frequency doubling crystal in the terminal optical system is calibrated by a pair of target field pyramids, which can be moved in and out. The pyramids are moved into the main optical path and placed symmetrically in front of the crystal relative to its center line to calibrate the near-field position of the crystal. Before the main laser enters the terminal optical system, it illuminates the pyramids and is reflected. The reflected light is reflected by TM4, TM3, TM2, and TM1, and then enters the main amplification system optical path: after passing through TSF-L2, the fourth hole of the TSF filter aperture, TSF-L1, and the first amplification medium, it is reflected by RM1 and P1, amplified four times, and reflected back by P1 and RM1. It then passes through the first amplification medium, TSF-L1, and the first hole of the TSF filter aperture again, and is reflected by a right-angle prism to the near-field monitoring system. After passing through a beam-shrinking lens, an imaging mirror, the first imaging lens, and the second imaging lens, the reflected light from the pyramids is received by the near-field camera. The center of the pyramidal light spot represents the center of the crystal.

[0026] Step 6. The deviation between the center of the reflected light spot of the corner pyramid in the near-field camera and the center of the light spot of the near-field reference small beam is the positional deviation between the near-field center of the crystal and the near-field center of the main beam. The second adjusting mirror TM3 and the third adjusting mirror TM4 in front of the crystal are adjusted using the feedback system until the deviation is within the error range, indicating that the near-field position of the crystal is aligned.

[0027] Step 7. After adjusting the collimation, move the cone out of the optical path and turn off the near-field reference light source.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1) By precisely placing the near-field reference beam and the pyramid, automatic detection and adjustment of the near-field center position of the crystal are achieved. Compared with traditional manual adjustment methods, this system can significantly reduce adjustment time and improve crystal collimation efficiency. This is undoubtedly an important improvement for high-power laser devices that require frequent crystal position adjustments.

[0030] 2) The system utilizes a feedback system to precisely adjust the front reflector of the crystal, ensuring that the deviation between the center of the cone-shaped reflected beam and the center of the near-field reference beam is adjusted to an extremely small error range. This high-precision adjustment method ensures the accuracy of the near-field position of the crystal, thereby improving the overall debugging accuracy of the laser device. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the optical path of the near-field center position deviation detection system of the crystal in the six-stage amplified high-power laser device of this embodiment.

[0032] Figure 2 These are the near-field images of the main beam and the light spot pairs of the small beam passing through the fourth aperture in a near-field camera.

[0033] Figure 3 These are the detection images of the cone-shaped reflected light spot and the small beam spot passing through the first aperture in the near-field camera.

[0034] Figure 1 In the middle: 1 - Near-field reference beam pair passing through the first aperture;

[0035] 2 - Near-field reference through the fourth aperture small beam pair;

[0036] 3-First injection mirror In-M1, 4-Second injection mirror In-M2, 5-Third injection mirror In-M3, 6-Injection lens, 7-First mirror P0, 8-Right-angle prism, 9-First aperture of transmission space filter, 10-Fourth aperture of transmission space filter, 11-Focusing lens TSF-L1 of transmission space filter, 12-First amplifying medium, 13-First adjusting mirror RM1, 14-Motor controlling the movement of the mirror, 15-Cavity mirror CM1, 16-Second mirror P1, 17-Polarization converter PEPC, 18-Cavity space filter lens CSF-L1, 19-Cavity space filter aperture (four apertures in total), 20-Cavity space filter lens CSF-L2, 21-Second amplifying medium, 22-Cavity mirror CM2, 23-Transmission space filter lens TSF-L2, 24-Third mirror TM1 25 – Fourth reflecting mirror TM2, 26 – Second adjusting reflecting mirror TM3, 27 – Third adjusting reflecting mirror TM4, 28 – A pair of pyramids, 29 – Terminal optical system, 30 – Crystal, 31 – Beam-shrinking lens, 32 – Imaging mirror, 33 – First imaging lens, 34 – Second imaging lens, 35 – Near-field detection camera Detailed Implementation

[0037] The present patent will be further described below with reference to the embodiments and accompanying drawings, but this should not be construed as limiting the scope of protection of the present patent.

[0038] The near-field center position deviation detection system for a six-pass amplified high-power laser device provided in this embodiment aims to ensure that the crystal in the high-power laser device is accurately aligned with the main beam. Through the ingenious placement of a near-field reference beam and a corner cone, the system can precisely locate the near-field center of the main beam and the crystal center, and automatically detect the deviation between them. Once a deviation is detected, the system uses a feedback system to adjust the crystal until it is perfectly aligned.

[0039] Please refer to the following first. Figure 1 , Figure 1 This is a schematic diagram of the optical path of the near-field center position deviation detection system for a six-pass amplified high-power laser device crystal, as shown in the figure. The system comprises:

[0040] Near-field reference beam: Composed of two pairs of small beams 1 and 2 placed behind the first adjusting mirror 13. These two pairs of small beams coincide in the near-field position, but have different far-field angles. They pass through the first aperture 9 and the fourth aperture 10 of the transmission space filter, respectively, and are therefore also called the small beam pair passing through the first aperture and the small beam pair passing through the fourth aperture.

[0041] Pyramid 28: A pair of target field pyramids 28 are placed in front of the crystal 30 to calibrate the near-field position of the crystal. The pyramids can be moved in and out, facilitating flexible use during testing and adjustment.

[0042] Second adjusting mirror TM3 (26) and third adjusting mirror TM4 (27): located in front of the cone 28, used to adjust the path of the light reflected from the cone.

[0043] The right-angle prism 8 can be moved behind the first aperture 9 and the fourth aperture 10 of the transmission space filter to change the path of the beam and allow it to enter the near-field detection system.

[0044] The near-field detection system consists of a beam-shrinking lens 31, an imaging mirror 32, a first imaging lens 33, a second imaging lens 34, and a near-field detection camera 35. It is capable of acquiring near-field images of the main beam and the reference beam and measuring the deviation between them.

[0045] The method for detecting near-field center deviation of a crystal using the above-mentioned detection system includes the following steps:

[0046] Step 1. Place the near-field reference beam: Place two pairs of small beams 1 and 2 behind the first adjusting mirror 13, ensuring that they coincide in the near-field position and have different far-field angles. The far-field pointing of the beam pairs passes through the first aperture 9 and the fourth aperture 10 respectively, hence they are distinguished as small beam pair 1 passing through the first aperture and small beam pair 2 passing through the fourth aperture.

[0047] Step 2. Determine the near-field reference of the main beam: Adjust the main beam using the small beam pair 2 passing through the fourth aperture so that its near-field center coincides with the near-field center of the small beam pair. That is, the near-field reference position of the main beam is determined by the small beam pair 2 placed after RM1 (13) passing through the fourth aperture.

[0048] The optical path of the main beam of the six-pass amplified high-power laser device is shown in the figure. The main beam from the preamplifier is injected into the first aperture (9) of the transmission space filter through three injection mirrors (3, 4, 5), and then passes through the transmission space filter lens TSF-L1. (11) The beam becomes a parallel beam, passes through the first amplifying medium 12, and is reflected by the first adjusting mirror RM1 (13) and the second mirror P1 (16). It then enters the cavity space filter and is amplified in four stages: after being focused by the cavity space filter focusing lens CSF-L1 (18), it passes through the first hole of the cavity space filter aperture (19), and becomes a parallel beam after passing through the cavity space filter lens CSF-L2 (20). It is amplified by the second amplifying medium 21, reflected by the cavity mirror CM2 (22), and passes sequentially through the second amplifying medium 21, the cavity converging lens CSF-L2 (20), the second hole of the cavity filter aperture (19), the cavity converging lens CSF-L1 (18), and the polarization converter PEPC (17). After that, the beam passes sequentially through the cavity space mirror CM1 (15). PEPC (17) is turned off, and then passes sequentially through CSF-L1 (18), the third hole of the cavity space filter aperture (19), CSF-L2 (20), the second amplifying medium 21, CM2 (22), the second amplifying medium 21, CSF-L2 (20), the fourth hole of the cavity space filter aperture (19), and CSF-L1 (18). After these four amplifications, it is reflected by the second reflector P1 (16), and then through RM1 (13), the amplifying medium 12, TSF-L1 (11), the fourth hole of the transmission space filter aperture (10), the transmission space filter lens TSF-L2 (23), and finally reflected by the third reflector TM1 (24), the fourth reflector TM2 (25), the second adjustment reflector TM3 (26), and the third adjustment reflector TM4 (27) before being output to the terminal optical system 29 where the crystal 30 is located.

[0049] After the right-angle prism 8 is moved to the fourth hole (10) of the transmission space filter, the small beam pair (2) after being placed in RM1 (13) and passing through the fourth hole, together with the main beam after being amplified by four passes, passes through the first amplification medium 12 and TSF-L1 (11), passes through the fourth hole (10) of the transmission space filter, and is reflected by the right-angle prism 8 to the near-field detection system. It is then imaged by the beam-shrinking lens 31, the imaging mirror 32, the first imaging lens (33) and the second imaging lens (34) to the near-field detection camera 35, thereby obtaining the near-field image center of the main beam and the imaging spot of the small beam. The three injection mirrors 3, 4 and 5 in front of the amplification system are adjusted so that the near-field image center of the main beam coincides with the center of the spot pair of the small beam pair (2) passing through the fourth hole, so that the center of the small beam pair (2) passing through the fourth hole is used as the near-field reference of the main beam.

[0050] The near-field image of the main beam and the image of the small beam spot pair passing through the fourth aperture in the near-field camera are as follows: Figure 2 As shown. The gray area is a schematic diagram of the near-field image of the main laser, and the black circle represents the center of the near-field of the main laser. The white spots are the small beam spot pairs passing through the fourth aperture, and the center of the crosshairs is the center of the line connecting the spots. Adjust the three injection mirrors 3, 4, and 5 to make the two centers coincide.

[0051] Step 3. Verify another reference beam: The near-field positions of the small beam pair 1 through the first aperture of the TSF filter and the small beam pair 2 through the fourth aperture of the TSF filter coincide. Therefore, the near-field center of the small beam pair 1 through the first aperture also coincides with the near-field center of the main beam. Thus, the center of the small beam pair 1 through the first aperture is also used as the near-field reference of the main beam.

[0052] Step 4. Detecting the near-field reference small beam: After moving the right-angle prism 8 to the first aperture 9 of the TSF filter aperture, the small beam pair 1 passing through the first aperture passes through the first amplifying medium 12, TSF-L1 (11) and the first aperture 9, and is reflected by the right-angle prism 8 to the near-field detection system. After passing through the beam-shrinking lens 31, the imaging mirror 32, the first imaging lens (33) and the second imaging lens (34), it is received by the near-field detection camera and imaged as a pair of small light spots, such as... Figure 3 As shown, the center of the small spot pair represents the reference center of the near-field beam position, and the small beam pair 1 passing through the first aperture serves as the near-field reference small beam of the main beam for subsequent detection and adjustment.

[0053] Step 5. Calibrating the crystal position: At the other end, the position of the frequency doubling crystal 30 in the terminal optical system 29 is calibrated by a pair of target field pyramids 28, which can be moved in and out. The pyramids 28 are moved into the main optical path and placed symmetrically in front of the crystal 30 relative to the crystal centerline to calibrate the near-field position of the crystal. Before the main laser enters the terminal optical system 29, it will illuminate the pyramid 28 and reflect the light. After being reflected by a series of TM4 (27), TM3 (26), TM2 (25), and TM1 (24), the reflected light enters the main amplifier system optical path: after passing through TSF-L2 (23), the fourth hole of the TSF filter aperture (10), TSF-L1 (11), and the first amplification medium 12, it is reflected by RM1 (13) and P1 (16). After being amplified four times, it is reflected back by P1 (16) and RM1 (13). It then passes through the first amplification medium 12, TSF-L1 (11), and the first hole of the TSF filter aperture (9) again, and is reflected by the right-angle prism 8 to the near-field detection system. After passing through the beam-shrinking lens 31, the imaging mirror 32, the first imaging lens (33), and the second imaging lens (34), the reflected light from the pyramid is received by the near-field camera 35. The center of the pyramidal light spot represents the center of the crystal. Figure 3 As shown.

[0054] Step 6. Measurement Deviation: The deviation between the center of the reflected light spot of the pyramid in the near-field camera and the center of the light spot of the near-field reference small beam is the positional deviation between the near-field center of the crystal and the near-field center of the main beam. Figure 3 As shown. Figure 3 The two pairs of light spots are the pyramidal reflection light spot pair and the near-field reference small beam light spot pair, respectively. The white circle and crosshair represent the center of these two pairs of light spots.

[0055] Step 7. Adjust the crystal position: Use the feedback system to adjust the second adjustment mirror TM3 (26) and the third adjustment mirror TM4 (27) in front of the crystal so that the center position deviation of the two pairs of light spots is adjusted to the error range (so that the center of the pyramidal reflection light spot coincides with the center of the near-field reference small beam light spot), which means that the near-field position of the crystal has been adjusted and collimated.

[0056] Step 8. Complete the test: After adjusting the collimation, move the cone out of the optical path, turn off the near-field reference light source, and complete the test process.

[0057] This embodiment can detect the crystal center and the main beam center by placing a pyramid and a near-field reference beam, and automatically calibrate and adjust the near-field center position deviation of the crystal, thereby improving the crystal collimation efficiency and debugging accuracy. The system is characterized by simple equipment, easy adjustment and high accuracy.

Claims

1. A crystal near-field center position deviation detection system for a six-pass amplified high-power laser device, characterized in that, include: Two pairs of small beams are placed behind the first adjusting mirror RM1 to provide near-field reference. The near-field positions of the two pairs of small beams coincide, but their far-field angles are different. The far-field pointing of the beam pairs passes through different filter apertures of the transmission space filter. A pair of pyramids, which can be moved in and out of the crystal, are placed in front of the crystal to calibrate the near-field position of the crystal; The second adjusting mirror TM3 and the third adjusting mirror TM4 are positioned in front of the cone to adjust the beam path of the incident crystal. A right-angle prism, movable to different filter apertures of the transmission space filter, is used to reflect the beam to the near-field detection system; A near-field detection system is used to acquire and image near-field images of the main beam and reflected light spots from small beams and cones; The following steps are used to detect and adjust the near-field center position deviation of the crystal: a) By using different filter apertures of the transmission space filter, the near-field center of the main beam is adjusted to coincide with the near-field center of the small beam pair to determine the near-field reference of the main beam. b) Using another small beam pair as a near-field position reference, the beam is reflected to the near-field detection system for imaging after the right-angle prism is moved to the corresponding filter aperture; c) Move a pair of pyramids into the main optical path and place them symmetrically in front of the crystal relative to the crystal centerline. The main laser is reflected to the near-field detection system for imaging, and the center of the pyramidal reflected light spot is obtained. d) Compare the deviations of the near-field reference small beam from the center of the spot to the center of the cone-shaped reflected spot, and adjust the mirror groups TM3 and TM4 to bring the deviation within the predetermined error range, thereby achieving collimation of the near-field position of the crystal. It also includes a feedback system, which adjusts the second adjustment mirror TM3 and the third adjustment mirror TM4 according to the deviation between the center of the reflected light spot of the pyramid pair in the near-field camera and the center of the light spot of the near-field reference small beam pair, so that the deviation of the center position of the two pairs of light spots is adjusted to the error range. The near-field detection system comprises a beam-shrinking lens, an imaging mirror, a first imaging lens, a second imaging lens, and a near-field detection camera arranged sequentially along the optical path. The beam is imaged onto the near-field detection camera (35) through the beam-shrinking lens (31), the imaging mirror (32), the first imaging lens (33), and the second imaging lens (34) to obtain the near-field image center of the main beam and the imaging spot of the small beam.

2. The crystal near-field center position deviation detection system for a six-pass amplified high-power laser device according to claim 1, characterized in that, The optical path system of the six-pass amplified high-power laser device, after output from the preamplifier, sequentially includes a first injection mirror In-M1, a second injection mirror In-M2, a third injection mirror In-M3, an injection lens, a first mirror P0, a first and fourth aperture of the transmission space filter, a transmission space filter focusing lens TSF-L1, a first amplifying medium, a first adjusting mirror RM1, a cavity mirror CM1, a second mirror P1, a polarization converter PEPC, a cavity space filter lens CSF-L1, four cavity space filter apertures, a cavity space filter lens CSF-L2, a second amplifying medium, and a cavity mirror CM2. After double-pass amplification by the first amplifying medium and four-pass amplification by the second amplifying medium, the light is reflected by the third mirror TM1, the fourth mirror TM2, the second adjusting mirror TM3, and the third adjusting mirror TM4 to the terminal optical system where the crystal is located.

Images