High-beam-quality slab laser system based on stimulated Brillouin scattering

Abstract

The invention provides a high-beam-quality slab laser system based on stimulated Brillouin scattering, which is used for solving the technical problem that pulse laser output with high pulse energy, high repetition frequency and high beam quality is difficult to simultaneously appear in the prior art. The device comprises a seed light beam shaping module, a double-end pumping slab amplification module and a phase conjugation module which are arranged in sequence, single-longitudinal-mode seed laser output by the seed light beam shaping module is guided into the double-end pumping slab amplification module to be subjected to double-pass amplification, and the amplified laser enters the phase conjugation module; and after returning through the phase conjugation module, the laser enters the double-end pumping slab amplification module again to be subjected to four-pass amplification, and then KHz nanosecond high-beam-quality laser is output. The laser is amplified for four times back and forth between the phase conjugation module and the double-end pumping slab amplification module, and nanosecond pulse laser output with high repetition frequency, large energy and high beam quality is achieved.

Description

Technical Field

[0001] This invention relates to the technical field of high-power, high-beam-quality solid-state lasers, and more particularly to a high-beam-quality slab laser system based on stimulated Brillouin scattering. Background Technology

[0002] Solid-state lasers with high pulse energy, high repetition rate, and high beam quality ("three highs") have strong application demands in numerous fields such as industrial manufacturing, cutting-edge science, and optoelectronic warfare, and are of great significance to key areas prioritized by the nation. However, improving high pulse energy (high power) and maintaining high beam quality are mutually restrictive. Under strong pump loads, a large amount of waste heat generates a temperature gradient in the gain medium and causes thermo-optical distortion, deteriorating the beam quality of the output laser. This will affect the efficiency of subsequent amplification and also poses a risk of damaging subsequent amplification modules.

[0003] To address the trade-off between beam quality and laser power enhancement, researchers have attempted to improve the heat dissipation efficiency of the gain medium by altering its shape, thereby reducing the temperature gradient difference and mitigating optical distortion caused by this gradient. This led to the development of slab lasers, which primarily modify the gain medium to a slab shape, utilizing the large sidewalls for heat dissipation, reducing the slab thickness, and mitigating thermal effects along the thickness direction. A zigzag propagation pattern was also designed to address the impact of thickness-direction thermal effects on beam quality, thus improving the beam quality of high-power lasers to some extent. However, the thermal effect along the height of the slab was not significantly improved, ultimately resulting in no substantial improvement in the output beam quality of the slab laser.

[0004] Stimulated Brillouin Scattering (SBS) phase conjugation can also effectively improve the beam quality of laser output. At low repetition rates, numerous studies have shown that SBS phase conjugation can significantly optimize the beam intensity distribution of the laser output. However, in high-repetition-rate, high-energy laser systems, the optical breakdown effect at the focal point within the SBS medium is severe, and it also exhibits thermal convection and thermal defocusing effects, which further degrade beam quality.

[0005] Therefore, with current technology, it is difficult to simultaneously achieve pulsed laser output with high pulse energy, high repetition rate, and high beam quality, which will affect the further improvement of laser system power and amplification efficiency, and thus affect the further development of solid-state lasers. Summary of the Invention

[0006] To address the technical problem that current technologies cannot simultaneously achieve high pulse energy, high repetition rate, and high beam quality pulsed laser output, this invention proposes a high beam quality slab laser system based on stimulated Brillouin scattering. The laser undergoes four amplification cycles between a phase conjugation module and a dual-ended pumped slab amplification module, thereby achieving high repetition rate, high energy, and high beam quality nanosecond pulsed laser output.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A high beam quality slab laser system based on stimulated Brillouin scattering includes a seed beam shaping module, a double-ended pumped slab amplification module, and a phase conjugation module arranged sequentially. The single longitudinal mode seed laser output from the seed beam shaping module is introduced into the double-ended pumped slab amplification module for double-pass amplification. The amplified laser enters the phase conjugation module, returns through the phase conjugation module, and then re-enters the double-ended pumped slab amplification module for four-pass amplification before outputting a kilohertz nanosecond high beam quality laser.

[0008] Preferably, the seed laser beam shaping module includes a seed laser, an optical isolator, and a beam shaping structure arranged sequentially, with the centers of the seed laser, the optical isolator, and the beam shaping structure on the same horizontal line.

[0009] Preferably, the beam shaping structure includes a first shaping mirror and a second shaping mirror arranged in sequence, with the centers of the first shaping mirror and the second shaping mirror on the same horizontal line as the center of the seed laser.

[0010] Preferably, the dual-ended pumped slab amplifier module includes a slab amplifier, with a first reflection mechanism and a second reflection mechanism respectively provided on both sides of the slab amplifier. The first reflection mechanism is located between the output of the seed beam shaping module and the slab amplifier, and the second reflection polarization mechanism is located on the rear side of the slab amplifier. The seed beam amplified by the slab amplifier is transmitted to the phase conjugate module through the fifth reflector, and the seed beam amplified by the slab amplifier is output through the first reflection mechanism. The first reflection mechanism guides the rectangular light spot into the slab amplifier for amplification, and the second reflection mechanism guides the amplified laser back into the slab amplifier for amplification.

[0011] Preferably, the first reflection mechanism includes a first reflector, a second reflector, and a polarizer. The first reflector and the second shaping mirror at the output end of the seed beam shaping module are on the same horizontal line. The first and second reflectors are arranged in parallel. The polarizer is arranged in the reflected light path between the second reflector and the slab amplifier. A seventh reflector for outputting the four-pass amplified laser is provided in the reflected light path of the polarizer. The second reflection mechanism includes a third reflector and a fourth reflector, which are disposed on the output optical path or reflected optical path behind the slat amplifier.

[0012] Preferably, the seed laser is a single-longitudinal-mode laser, specifically a ring-cavity electro-optic Q-switched laser with a repetition rate of 1 kHz; the seed laser generates a 1 kHz millijoule-level single-longitudinal-mode seed laser, and the output circular spot size is a single-longitudinal-mode seed laser of 2 mm. The first reshaping lens is a spherical plano-concave cylindrical lens with dimensions of 25×25×8 mm. 3 The second reshaping lens is a spherical plano-convex cylindrical lens with dimensions of 100×15×22 mm. 3 The focal length of the first reshaping lens is -20 mm, and the focal length of the second reshaping lens is 150 mm. The dimensions of the slab amplifier are 3×25×88 mm. 3 ; The slat amplifier has a front pump light at one end and an end pump light at the other end.

[0013] Preferably, the phase conjugation module includes a sixth reflecting mirror, a quarter-wave plate, a convex lens, and a temperature-controlled SBS dielectric cell arranged sequentially. The sixth reflecting mirror is arranged parallel to the fifth reflecting mirror, and the centers of the sixth reflecting mirror, the quarter-wave plate, the convex lens, and the temperature-controlled SBS dielectric cell are on the same horizontal line. The double-pass amplified laser enters and is focused in the temperature-controlled SBS dielectric cell through the sixth reflecting mirror, the quarter-wave plate, and the convex lens to complete phase conjugation, generating backscattered laser. The distortion of the amplified spot shape is optimized by the phase conjugation characteristics of SBS.

[0014] Preferably, the temperature-controlled SBS medium pool includes two frustum-shaped medium pools, with a TEC temperature-controlled heat sink module located at the focal point between the two medium pools; a front window mirror is located on one side of the front medium pool, and a rear window mirror is located on the other side of the front and rear medium pools; a medium filling port is located at the end of the rear medium pool.

[0015] Preferably, the TEC temperature control heat sink module includes a conical copper heat sink, a TEC, and a water-cooling block. The upper and lower surfaces of the conical copper heat sink are provided with TECs, and the water-cooling block is fixed on the heat dissipation surface of the TEC. The two ends of the water-cooling block are respectively provided with a water inlet and a water outlet.

[0016] Preferably, the focal length of the convex lens is 150 mm.

[0017] The medium in the medium pool is an electronic fluorinated liquid; Both the front and rear window mirrors are 1064 nm high-transmittance film windows; The cross-sectional dimensions of the conical copper heat sink are 20×20 mm.2 The thickness is 10 mm; the TEC size is 10×10 mm. 2 ; The conical copper heat sink has a conical through hole in the middle, and the two medium pools are connected through the conical through hole; The upper and lower surfaces of the conical copper heat sink are connected to the TEC via thermally conductive silicone grease.

[0018] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are: 1. This invention proposes a slatted four-pass amplification phase conjugate structure, which can effectively improve the amplification efficiency of the amplifier and compensate for optical distortion.

[0019] 2. Design the heat dissipation structure of the SBS dielectric cell to avoid the breakdown effect of high-power laser and uneven temperature distribution within the dielectric, thereby improving the beam quality of the amplified laser. 3. This laser slab laser system can achieve high beam quality laser output of kilohertz and 300 mJ in nanoseconds. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is the optical path diagram of the present invention.

[0022] Figure 2 This is a structural diagram of the temperature-controlled SBS medium pool of the present invention.

[0023] Figure 3 This is a structural diagram of the TEC temperature control heat sink module of the present invention.

[0024] The reference numerals in the attached diagram are explained as follows: 1 is the seed beam shaping module; 2 is the dual-ended pumped slab amplification module; 3 is the phase conjugation module; and 1-1 is the seed laser; 1-2 is the optical isolator; 1-3 is the first shaping mirror; 1-4 is the second shaping mirror. 2-1 is the first reflecting mirror; 2-2 is the second reflecting mirror; 2-3 is the polarizer; 2-4 is the slab amplifier; 2-5 is the third reflecting mirror; 2-6 is the fourth reflecting mirror; 2-7 is the fifth reflecting mirror; 2-8 is the front pump light; 2-9 is the end pump light; 2-10 is the seventh reflecting mirror; 3-1 is the sixth reflecting mirror; 3-2 is a quarter-wave plate; 3-3 is a convex lens; 3-4 is a temperature-controlled SBS dielectric cell; 3-4-1 is the front window mirror; 3-4-2 is the media tank; 3-4-3 is the TEC temperature-controlled heat sink module; 3-4-4 is the media filling port; 3-4-5 is the rear window mirror; 3-4-3-1 is a conical copper heat sink; 3-4-3-2 is a TEC; 3-4-3-3 is a water cooling block; 3-4-3-4 is the water inlet; 3-4-3-5 is the water return outlet. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, a high-beam-quality slab laser system based on stimulated Brillouin scattering includes a seed beam shaping module 1, a double-ended pumped slab amplification module 2, and a phase conjugation module 3 arranged sequentially. The single-longitudinal-mode seed laser output from the seed beam shaping module 1 is fed into the double-ended pumped slab amplification module 2 for double-pass amplification. The amplified laser then enters the phase conjugation module 3, returns through the phase conjugation module 3, and re-enters the double-ended pumped slab amplification module 2 for a fourth-pass amplification before output. This achieves kilohertz, 300 mJ nanosecond high-beam-quality laser output. The seed beam shaping module 1 generates the single-longitudinal-mode laser and shapes it to match the end face size of the slab amplifier. The double-ended pumped slab amplification module 2 performs the first and second amplifications of the single-longitudinal-mode seed laser and the third and fourth amplifications of the laser returned from the phase conjugation module 3. The phase conjugation module 3 effectively improves the amplification efficiency of the slab amplifier and compensates for optical distortion.

[0027] The seed laser beam shaping module 1 includes a seed laser 1-1, an optical isolator 1-2, and a beam shaping structure arranged sequentially, with the centers of the seed laser 1-1, optical isolator 1-2, and beam shaping structure on the same horizontal line. The seed laser 1-1 is a single-longitudinal-mode laser, a ring-cavity electro-optic Q-switched laser with a repetition rate of 1 kHz, outputting millijoule-level single-longitudinal-mode nanosecond pulse laser. The seed laser 1-1 generates a 1 kHz millijoule-level single-longitudinal-mode seed laser, with an output circular spot size of 2 mm, the size of which is related to the gain medium. The linewidth of the single-longitudinal-mode seed laser is 100 MHz, improving the SBS breakdown threshold while ensuring SBS reflectivity. The optical isolator 1-2 prevents damage to the seed laser from specular reflection beams and slab amplifier return light, thereby protecting the seed laser 1-1.

[0028] The beam shaping structure includes a first shaping mirror 1-3 and a second shaping mirror 1-4 arranged sequentially. The centers of the first shaping mirror 1-3 and the second shaping mirror 1-4 are on the same horizontal line as the center of the seed laser 1-1. The first shaping mirror 1-3 and the second shaping mirror 1-4 shape the single-longitudinal-mode laser beam. The first shaping mirror 1-3 is a spherical plano-concave cylindrical lens with dimensions of 25×25×8 mm. 3 The second reshaping lens 1-4 is a spherical plano-convex cylindrical lens with a lens size of 100×15×22 mm. 3 Lens size affects beam quality. If the lens is too small, significant spherical aberration will occur; if the lens is too large, the overall size and weight of the laser will increase. The two lenses work together to elongate the beam spot vertically to 18 mm, thus shaping a 2 mm circular spot into a 2×18 mm beam. 2 A rectangular spot of light.

[0029] A single-longitudinal-mode seed laser with a spot size of 2 mm passes through an optical isolator 1-2 and enters a first shaping mirror 1-3 with a focal length of -20 mm and a second shaping mirror 1-4 with a focal length of 150 mm, shaping the circular seed laser beam into a 2×18 mm beam. 2 A rectangular laser spot is formed, and the beam divergence angle is optimized to match the enlarged size of the slat end face. The focal length affects the collimation, beam quality, and beam transmission distance of the laser transmission.

[0030] The dual-ended pumped slab amplifier module 2 includes a slab amplifier 2-4. A first reflection mechanism and a second reflection mechanism are respectively located on both sides of the slab amplifier 2-4. The first reflection mechanism is positioned between the second shaping mirror 1-4 of the seed beam shaping module 1 and the slab amplifier 2-4. The second reflection mechanism is located behind the slab amplifier 2-4. The seed beam output from the slab amplifier 2-4 is transmitted to the phase conjugate module 3 via a fifth reflection mirror 2-7. The function of the fifth reflection mirror 2-7 is to reflect the laser beam; its placement is not critical. The first reflection mechanism guides the rectangular light spot into the slab amplifier 2-4 for amplification, and the second reflection mechanism guides the amplified laser beam back into the slab amplifier 2-4 for further amplification, thus achieving dual-path amplification. The first reflecting mechanism includes a first reflecting mirror 2-1, a second reflecting mirror 2-2, and a polarizer 2-3. The first reflecting mirror 2-1 and the second shaping mirror 1-4 are on the same horizontal line and are arranged parallel to each other. The polarizer 2-3 is positioned in the reflected light path between the second reflecting mirror 2-2 and the slab amplifier 2-4. The function of the first reflecting mirror 2-1 is to reflect the laser, the function of the second reflecting mirror 2-2 is to reflect the laser, and the function of the polarizer 2-3 is to work with a quarter-glass plate to reflect the amplified laser light after four passes. The second reflecting mechanism includes a third reflecting mirror 2-5 and a fourth reflecting mirror 2-6. The third reflecting mirror 2-5 and the fourth reflecting mirror 2-6 are positioned in the output light path or the reflected light path of the slab amplifier 2-4. The function of the third reflecting mirror 2-5 and the fourth reflecting mirror 2-6 is to reflect the laser, and their positions are not required.

[0031] A seventh reflecting mirror 2-10 is provided in the reflected light path of polarizer 2-3. The function of the seventh reflecting mirror 2-10 is to reflect the laser.

[0032] The rectangular light spot is first amplified by the first reflecting mirror 2-1, the second reflecting mirror 2-2 and the polarizer 2-3. After the first amplification, it is then amplified a second time by the third reflecting mirror 2-5 and the fourth reflecting mirror 2-6, thus achieving double amplification and outputting laser light.

[0033] One end of the slab amplifier 2-4 is provided with a front-end pump light 2-8, and the other end of the slab amplifier 2-4 is provided with a terminal pump light 2-9, forming a pump light pumping slab amplifier. The pump light is absorbed by the gain medium of the amplifier, thereby increasing the amplification factor of the amplifier.

[0034] The dimensions of the slab amplifier 2-4 in the dual-ended pumped slab amplifier module 2 are 3×25×88 mm. 3 The front-end pump light 2-8 and the end-end pump light 2-9 are reflected by the slab end face of the slab amplifier 2-4 and enter the interior of the slab gain medium. The slab dissipates heat through the microchannel heat sink, which can efficiently dissipate the waste heat generated by the slab amplifier.

[0035] The phase conjugation module 3 includes a sixth reflecting mirror 3-1, a quarter-wave plate 3-2, a convex lens 3-3, and a temperature-controlled SBS dielectric cell 3-4 arranged sequentially. The sixth reflecting mirror 3-1 is arranged parallel to the fifth reflecting mirror 2-7. The centers of the sixth reflecting mirror 3-1, the quarter-wave plate 3-2, the convex lens 3-3, and the temperature-controlled SBS dielectric cell 3-4 are on the same horizontal line. The function of the quarter-wave plate 3-2 is to transform the horizontal polarization state of the laser into a vertical polarization state. The function of the sixth reflecting mirror 3-1 is to focus the laser in the temperature-controlled SBS dielectric cell, generating backscattered laser light. The convex lens 3-3 with a focal length of 150mm can improve the laser power density, easily generate backscattered laser light, and at the same time, the laser pulse width is not compressed.

[0036] The laser beam, after being amplified twice, enters and is focused in the temperature-controlled SBS dielectric cell 3-4 through the sixth reflecting mirror 3-1, quarter-wave plate 3-2, and convex lens 3-3 to complete phase conjugation (automatically generating backscattered laser beam after focusing). The beam quality is further optimized by strictly controlling the temperature of the focal point in the temperature-controlled SBS dielectric cell 3-4, ensuring high beam quality laser output after the third and fourth amplifications. After passing through the phase conjugation module 3, the laser beam re-enters the double-ended pumped slab amplification module 2, and after the third and fourth amplifications, high repetition rate, high energy, and high beam quality nanosecond pulse laser output is achieved.

[0037] The phase conjugation module 3 focuses the double-pass magnified light spot of the slab into the temperature-controlled SBS dielectric cell 3-4 through the convex lens 3-3 with a focal length of 150 mm. The dielectric cell is filled with FC-72 liquid (electronic fluorinated liquid) to generate backscattered laser. The magnified distorted light spot morphology is optimized by the SBS phase conjugation characteristics.

[0038] like Figure 1 As shown, the single-longitudinal-mode seed laser is stretched to 18 mm in the vertical direction by optical isolator 1-2 and first shaping mirror 1-3 with a focal length of -20 mm. Then, the laser beam in the vertical direction is shaped to 2×18 mm by second shaping mirror 1-4. 2A rectangular collimated beam is output; the shaped beam is guided into a slab amplifier 2-4 through the first reflecting mirror 2-1, the second reflecting mirror 2-2, and the polarizer 2-3. The front pump light 2-8 and the end pump light 2-9 are guided into the interior of the slab amplifier 2-4 from both ends of the slab amplifier 2-4, respectively, to achieve the first-pass amplification of the seed light; after amplification, the seed light is guided into the slab amplifier 2-4 for the second time through the third reflecting mirror 2-5 and the fourth reflecting mirror 2-6, to achieve double-pass amplification; the double-pass amplified laser light is then guided into the slab amplifier 2-4 through the fifth reflecting mirror 2-7, the sixth reflecting mirror 3-1, the quarter-wave plate 3-2, and a focal length of 150. A convex lens 3-3 (mm) is introduced into a temperature-controlled SBS dielectric cell 3-4. Through the backscattering and phase conjugation properties of SBS, the beam quality is further optimized and the beam is returned through the convex lens 3-3, quarter-wave plate 3-2, sixth reflector 3-1, and fifth reflector 2-7 to be introduced into the slab amplifier 2-4 for the third time. Then, it is introduced into the slab amplifier 2-4 for the fourth time through the fourth reflector 2-6 and the third reflector 2-5 to achieve overall four-pass amplification. Finally, a high beam quality laser output of kilohertz and 300 mJ is achieved through polarizer 2-3 and seventh reflector 2-10.

[0039] like Figure 2 As shown, the temperature-controlled SBS dielectric cell 3-4 includes two frustum-shaped dielectric cells 3-4-2, with a TEC temperature-controlled heat sink module 3-4-3 located between them. The dielectric cells 3-4-2 hold the dielectric, while the TEC temperature-controlled heat sink module 3-4-3 precisely controls the temperature of the copper heat sink. A front window mirror 3-4-1 is located on one side of the front dielectric cell 3-4-2, serving as the input to the optical path of the temperature-controlled SBS dielectric cell 3-4. A rear window mirror 3-4-5 is located on the other side of the rear dielectric cell 3-4-2. Both the front and rear window mirrors 3-4-1 and 3-4-5 seal the dielectric cell. Both are 1064 nm high-transmittance films, allowing for high-efficiency laser transmission. A dielectric filling port 3-4-4 is located on the rear dielectric cell 3-4-2.

[0040] The temperature-controlled SBS dielectric cell 3-4 is designed in a dumbbell shape to facilitate heat dissipation at the focal point. 1064 nm high-transmittance film windows are bonded to both ends of the temperature-controlled SBS dielectric cell 3-4. The focal point is occupied by a 10 mm long TEC temperature-controlled heat sink module 3-4-3, which precisely controls the temperature of the copper heat sink. Since the laser enters the temperature-controlled SBS dielectric cell 3-4 in a gradually focusing manner, the dielectric cell 3-4-2 is designed in a dumbbell shape and made of transparent glass. This facilitates observation of the laser focal point within the dielectric cell and allows for adjustment of the dielectric cell's configuration. The end of the dielectric cell houses the dielectric filling port 3-4-4 for easy dielectric filling. The middle section of the dielectric cell contains the TEC temperature-controlled heat sink module 3-4-3, which helps reduce the temperature at the focal point, prevents SBS dielectric breakdown, and effectively improves the stability of the SBS phase conjugation.

[0041] The cross-sectional dimensions of the copper are 20×20 mm. 2 10×10 mm slabs are set on the upper and lower surfaces of the copper. 2 The TEC3-4-3-2 has a water-cooling block fixed on its heat dissipation surface. The water-cooling block removes heat from the TEC, and a high-precision temperature control system controls the temperature distribution of the medium at the focal point, preventing SBS medium breakdown while optimizing beam quality.

[0042] like Figure 3 As shown, the TEC temperature control heat sink module 3-4-3 includes: a conical copper heat sink 3-4-3-1, a TEC 3-4-3-2, a water cooling block 3-4-3-3, a water inlet 3-4-3-4, and a water outlet 3-4-3-5. The function of the conical copper heat sink 3-4-3-1 is to control the temperature of the medium pool through efficient heat conduction of copper. The conical shape matches the morphology of the laser. The cross-sectional dimensions of the conical copper heat sink 3-4-3-1 are 20×20 mm. 2 It can effectively dissipate heat, and 10×10mm heat sinks are provided on both the upper and lower surfaces of the conical copper heat sink 3-4-3-1. 2 The TEC 3-4-3-2 precisely controls the temperature of the copper heat sink. A water-cooled block 3-4-3-3 is fixed to the heat dissipation surface of the TEC 3-4-3-2. The water-cooled block 3-4-3-3 removes the heat from the TEC 3-4-3-2. A high-precision temperature control system controls the temperature distribution of the medium at the focal point. By adjusting the TEC temperature, the temperature of the copper heat sink is controlled, which in turn controls the temperature of the medium pool, preventing SBS medium breakdown while optimizing beam quality.

[0043] The conical copper heat sink 3-4-3-1 has a square cross-section and a thickness of 10 mm, with a conical through-hole in the middle. Two dielectric cells 3-4-2 are connected through this conical through-hole, which facilitates the output of the remaining laser light. The laser focus is located within the conical through-hole (where the lens focuses), facilitating efficient heat dissipation of the dielectric at the focal point. The upper and lower surfaces of the conical copper heat sink 3-4-3-1 are connected to the TEC 3-4-3-2 via thermal grease. The thermal grease ensures a tight bond between the TEC and the copper heat sink, preventing air pockets that would affect heat dissipation efficiency. The TEC allows for efficient and precise temperature control of the conical copper heat sink 3-4-3-1. The heat dissipation surface of the TEC 3-4-3-2 is connected to an aluminum alloy water-cooling block 3-4-3-3, which removes waste heat from the TEC 3-4-3-2. The water-cooled block has an inlet (3-4-3-4) on the left and an outlet (3-4-3-5) on the right. Water circulation keeps the water-cooled block (3-4-3-3) at a relatively stable temperature. This structure enables efficient temperature control and effectively prevents high-power lasers from breaking down in the dielectric cell.

[0044] Unless otherwise specified, the model numbers of the various devices in this embodiment of the invention are not limited; any device capable of performing the above functions is acceptable. Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the above-mentioned embodiment numbers are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high beam quality slab laser system based on stimulated Brillouin scattering, characterized in that, The application relates to a kHz nanosecond high-brightness laser device, which comprises a seed light beam shaping module (1), a double-end pumped slab amplification module (2) and a phase conjugation module (3) arranged in sequence.

2. The high beam quality slab laser system based on stimulated Brillouin scattering of claim 1, wherein, The seed light beam shaping module (1) comprises a seed laser (1-1), an optical isolator (1-2) and a beam shaping structure arranged in sequence, and the centers of the seed laser (1-1), the optical isolator (1-2) and the beam shaping structure are on the same horizontal line.

3. The high beam quality slab laser system based on stimulated Brillouin scattering according to claim 2, characterized in that The beam shaping structure comprises a first shaping mirror (1-3) and a second shaping mirror (1-4) arranged in sequence, and the centers of the first shaping mirror (1-3) and the second shaping mirror (1-4) and the center of the seed laser (1-1) are on the same horizontal line.

4. The high beam quality slab laser system based on stimulated Brillouin scattering according to any of claims 1 to 3, characterized in that The double-end pumped slab amplification module (2) comprises a slab amplifier (2-4), and first and second reflection mechanisms are arranged on the two sides of the slab amplifier (2-4), the first reflection mechanism is arranged between the output of the seed light beam shaping module (1) and the slab amplifier (2-4), the second reflection mechanism is arranged on the rear side of the slab amplifier (2-4), the double-pass amplified seed light output by the slab amplifier (2-4) is transmitted to the phase conjugation module (3) through a fifth reflecting mirror (2-7), and the four-pass amplified seed light output by the slab amplifier (2-4) is output through the first reflection mechanism. The first reflection mechanism guides the rectangular light spot into the slab amplifier (2-4) to amplify, and the second reflection mechanism guides the amplified laser into the slab amplifier (2-4) again to amplify.

5. The high beam quality slab laser system based on stimulated Brillouin scattering according to claim 4, characterized in that The first reflection mechanism comprises a first reflecting mirror (2-1), a second reflecting mirror (2-2) and a polarizer (2-3), the first reflecting mirror (2-1) is on the same horizontal line as the second shaping mirror (1-4) of the output end of the seed light beam shaping module (1), the first reflecting mirror (2-1) and the second reflecting mirror (2-2) are arranged in parallel, and the polarizer (2-3) is arranged on the reflected light path between the second reflecting mirror (2-2) and the slab amplifier (2-4); a seventh reflecting mirror (2-10) for outputting the four-pass amplified laser is arranged on the reflected light path of the polarizer (2-3). The second reflection mechanism comprises a third reflecting mirror (2-5) and a fourth reflecting mirror (2-6), and the third reflecting mirror (2-5) and the fourth reflecting mirror (2-6) are arranged on the output light path or the reflected light path on the rear side of the slab amplifier (2-4).

6. The high beam quality slab laser system based on stimulated Brillouin scattering according to claim 5, characterized in that The seed laser (1-1) is a single-longitudinal-mode laser, which is a ring cavity electro-optic Q-switched laser with a repetition frequency of 1 kHz; the seed laser (1-1) generates 1kHz millijoule single-longitudinal-mode seed laser, and the output circular light spot size of the single-longitudinal-mode seed laser is 2mm. The first shaping mirror (1-3) is a spherical plano-concave cylindrical lens, with dimensions of 25x25x8 mm 3 ; the second shaping mirror (1-4) is a spherical plano-convex cylindrical lens, with dimensions of 100x15x22 mm 3 ; the focal length of the first shaping mirror (1-3) is -20 mm, and the focal length of the second shaping mirror (1-4) is 150 mm; The dimensions of the slat amplifier (2-4) are 3 x 25 x 88 mm 3 ; One end of the slab amplifier (2-4) is provided with front end pump light (2-8), the other end of the slab amplifier (2-4) is provided with end pump light (2-9).

7. The high beam quality slab laser system based on stimulated Brillouin scattering according to any of claims 1 to 3, 5, 6, characterized in that The phase conjugation module (3) comprises a sixth mirror (3-1), a quarter wave plate (3-2), a convex lens (3-3) and a temperature control SBS medium pool (3-4) arranged in sequence, the sixth mirror (3-1) is arranged in parallel with the fifth mirror (2-7), the centers of the sixth mirror (3-1), the quarter wave plate (3-2), the convex lens (3-3) and the temperature control SBS medium pool (3-4) are on the same horizontal line; the double-pass amplified laser passes through the sixth mirror (3-1), the quarter wave plate (3-2) and the convex lens (3-3) to enter and focus in the temperature control SBS medium pool (3-4) to complete phase conjugation, generate backscattering laser, and the SBS phase conjugation characteristic is used to optimize the distorted spot morphology after amplification.

8. The high beam quality slab laser system based on stimulated Brillouin scattering according to claim 7, characterized in that The temperature control SBS medium pool (3-4) comprises two circular truncated cone-shaped medium pools (3-4-2), a TEC temperature control heat sink module (3-4-3) is arranged at the focal point position between the two medium pools (3-4-2); one side of the front-end medium pool (3-4-2) is provided with a front window mirror (3-4-1), the other side of the front and rear medium pools (3-4-2) is provided with a rear window mirror (3-4-5); the end position of the rear-end medium pool (3-4-2) is provided with a medium filling port (3-4-4).

9. The high beam quality slab laser system based on stimulated Brillouin scattering according to claim 8, characterized in that The TEC temperature control heat sink module (3-4-3) comprises a tapered copper heat sink (3-4-3-1), a TEC (3-4-3-2) and a water cooling block (3-4-3-3), the upper surface and the lower surface of the tapered copper heat sink (3-4-3-1) are provided with the TEC (3-4-3-2), the water cooling block (3-4-3-3) is fixed on the heat dissipation surface of the TEC (3-4-3-2), and the water inlet (3-4-3-4) and the water outlet (3-4-3-5) are arranged at two ends of the water cooling block (3-4-3-3) respectively.

10. The high beam quality slab laser system based on stimulated Brillouin scattering according to claim 9, characterized in that The focal length of the convex lens (3-3) is 150 mm; The medium in the medium pool (3-4-2) is electronic fluorination liquid; The front window mirror (3-4-1) and the rear window mirror (3-4-5) are both 1064 nm high-transparency film window pieces; The conical copper heat sink (3-4-3-1) has a cross-sectional dimension of 20 x 20 mm 2 , and a thickness of 10 mm; the TEC (3-4-3-2) has a dimension of 10 x 10 mm 2 ​ The middle of the tapered copper heat sink (3-4-3-1) is a tapered through hole, and the two medium pools (3-4-2) are connected through the tapered through hole; The upper surface and the lower surface of the tapered copper heat sink (3-4-3-1) are connected with the TEC (3-4-3-2) through heat-conducting silicone grease.

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