A laser amplifier

Abstract

The application discloses a kind of laser amplifiers, it is related to the field of laser technology, including: seed source, convex lens, first reflector, second reflector, optical isolator, polaroid, laser beam expander, cylindrical lens, slab crystal, heat sink, pump mirror, 1 / 4 wave plate, third reflector, first pump coupler, second pump coupler, first pump source and second pump source;First pump coupler is used to focus the pump light generated by first pump source on slab crystal to amplify laser power;Second pump coupler is located on the side of slab crystal, and the distance from slab crystal is adjustable, for adjusting the heat distribution in slab crystal based on the pump light generated by second pump source.The application can improve the energy and beam quality of amplified laser.

Description

Technical Field

[0001] This application relates to the field of laser technology, and more particularly to a laser amplifier. Background Technology

[0002] High-power lasers are widely used in industrial processing, aerospace, and other fields. In practical applications, due to issues such as damage to optical components and deterioration of beam quality, the laser power generated by the seed source cannot meet operational requirements. Therefore, it is necessary to further increase the laser power through a laser amplifier.

[0003] To increase laser power, existing laser amplifiers typically use slab crystals as the laser crystal. These crystals are flat and their length in the X-direction is usually 5-10 times that of conventional bulk crystals. The increased crystal volume allows for higher power pumping, thus providing higher power amplification for the laser. However, when large laser crystals are clamped in heat dissipation devices, the increased size introduces uneven stress, resulting in different laser divergence angles at different locations after amplification. This causes laser distortion and reduces the beam quality of the amplified laser. Summary of the Invention

[0004] In view of this, embodiments of this application provide a laser amplifier that can improve the energy and beam quality of the amplified laser.

[0005] In a first aspect, embodiments of this application provide a laser amplifier, including: a seed source, a convex lens, a first reflecting mirror, a second reflecting mirror, an optical isolator, a polarizer, a laser beam expander, a cylindrical lens, a slab crystal, a heat dissipation device, a pump mirror, a quarter-wave plate, a third reflecting mirror, a first pump coupler, a second pump coupler, a first pump source, and a second pump source.

[0006] The system includes: a convex lens for collimating the laser generated by the seed source; a first and a second reflecting mirror for changing the laser transmission direction; an optical isolator for isolating the amplified laser; a polarizer for transmitting horizontally polarized laser and reflecting vertically polarized laser; a laser beam expander for increasing the laser spot diameter; a cylindrical lens for focusing the laser in a single direction; a slab crystal for amplifying laser power; a heat dissipation device for clamping and cooling the slab crystal; a pump mirror for transmitting pump light and reflecting laser; a quarter-wave plate for changing the polarization state of the laser; a third reflecting mirror for reflecting laser; a first pump coupler for focusing the pump light generated by the first pump source onto the slab crystal to amplify laser power; and a second pump coupler located on the side of the slab crystal, with an adjustable distance from the slab crystal, for adjusting the heat distribution within the slab crystal based on the pump light generated by the second pump source.

[0007] The seed source, the convex lens, the first reflector, the second reflector, the optical isolator, the polarizer, the laser beam expander, the cylindrical lens, the slab crystal, the pump mirror, the quarter-wave plate, and the third reflector are arranged sequentially along the optical path; or, the seed source, the convex lens, the first reflector, the second reflector, the polarizer, the optical isolator, the laser beam expander, the cylindrical lens, the slab crystal, the pump mirror, the quarter-wave plate, and the third reflector are arranged sequentially along the optical path.

[0008] Optionally,

[0009] The laser emitted by the lath crystal is linearly polarized light.

[0010] Optionally,

[0011] Further includes: a third pump coupler and a third pump source;

[0012] The second pump coupler and the third pump coupler are located on opposite sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and it is used to adjust the heat distribution within the slab crystal based on the pump light generated by the third pump source.

[0013] Optionally,

[0014] The seed source is a mode-locked laser used to generate picosecond or femtosecond lasers.

[0015] Optionally,

[0016] The first reflector is a 45° reflector, the second reflector is a 45° reflector, and the third reflector is a total reflection mirror.

[0017] Secondly, embodiments of this application provide a laser amplifier, including: a seed source, a convex lens, a first reflecting mirror, a second reflecting mirror, an optical isolator, a polarizer, a laser beam expander, a cylindrical lens, a slab crystal, a heat dissipation device, a pump mirror, a quarter-wave plate, a third reflecting mirror, a first pump coupler, a second pump coupler, a first pump source, and a second pump source.

[0018] The system includes: a convex lens for collimating the laser generated by the seed source; a first and a second reflecting mirror for changing the laser transmission direction; an optical isolator for isolating the amplified laser; a polarizer for transmitting horizontally polarized laser and reflecting vertically polarized laser; a laser beam expander for increasing the laser spot diameter; a cylindrical lens for focusing the laser in a single direction; a slab crystal for amplifying laser power; a heat dissipation device for clamping and cooling the slab crystal; a pump mirror for transmitting pump light and reflecting laser; a quarter-wave plate for changing the polarization state of the laser; a third reflecting mirror for reflecting laser; a first pump coupler for focusing the pump light generated by the first pump source onto the slab crystal to amplify laser power; and a second pump coupler located on the side of the slab crystal, with an adjustable distance from the slab crystal, for adjusting the heat distribution within the slab crystal based on the pump light generated by the second pump source.

[0019] The seed source, the convex lens, the first reflector, the second reflector, the optical isolator, the polarizer, the laser beam expander, the cylindrical lens, the quarter-wave plate, the slab crystal, the pump mirror, and the third reflector are arranged sequentially along the optical path; or, the seed source, the convex lens, the first reflector, the second reflector, the polarizer, the optical isolator, the laser beam expander, the cylindrical lens, the quarter-wave plate, the slab crystal, the pump mirror, and the third reflector are arranged sequentially along the optical path.

[0020] Optionally,

[0021] The lath crystal is isotropic.

[0022] Optionally,

[0023] Further includes: a third pump coupler and a third pump source;

[0024] The second pump coupler and the third pump coupler are located on opposite sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and it is used to adjust the heat distribution within the slab crystal based on the pump light generated by the third pump source.

[0025] Optionally,

[0026] The seed source is a mode-locked laser used to generate picosecond or femtosecond lasers.

[0027] Optionally,

[0028] The first reflector is a 45° reflector, the second reflector is a 45° reflector, and the third reflector is a total reflection mirror.

[0029] One embodiment of the above invention has the following advantages or beneficial effects: the second pump coupler injects pump light into the slab crystal from the side of the slab crystal, and the position of the pump light in the slab crystal is adjusted by changing the distance between the second pump coupler and the slab crystal, thereby adjusting the heat distribution in the slab crystal, calibrating the distortion of the light spot after power amplification, and improving the quality of the amplified laser.

[0030] The further effects of the aforementioned unconventional alternative methods will be explained below in conjunction with specific implementation methods. Attached Figure Description

[0031] The accompanying drawings are provided to better understand this application and do not constitute an undue limitation thereof. Wherein:

[0032] Figure 1 This is a schematic diagram of a laser amplifier provided in one embodiment of this application;

[0033] Figure 2 This is a schematic diagram of a laser amplifier provided in another embodiment of this application;

[0034] Figure 3 This is a schematic diagram of a uniformly elliptical light spot provided in one embodiment of this application;

[0035] Figure 4 This is a schematic diagram of a distorted light spot provided in one embodiment of this application;

[0036] Figure 5 This is a schematic diagram showing a comparison of the light spot before and after optimization, provided in one embodiment of this application;

[0037] Figure 6 This is a schematic diagram of a laser amplifier provided in another embodiment of this application;

[0038] Figure 7 This is a schematic diagram of a laser amplifier provided in another embodiment of this application. Detailed Implementation

[0039] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0040] Small-sized bulk laser crystals, when pumped at high power, can reduce the beam quality after laser power amplification and increase the risk of crystal damage. To increase laser power, high-power pump light is typically used to pump larger laser crystals. These crystals are flat and usually 5-10 times longer than conventional crystals in the X-direction. The increased crystal volume allows for higher power pumping, thus providing higher power amplification for the laser. However, when large laser crystals are installed and clamped in metal heat sinks, the increased crystal size often introduces uneven stress. This uneven distribution of stress within the crystal leads to different laser divergence angles at different locations after amplification, causing beam distortion and reducing beam quality.

[0041] In view of this, such as Figure 1 As shown, this application embodiment provides a laser amplifier, including: a seed source 1, a convex lens 2, a first reflecting mirror 3, a second reflecting mirror 4, an optical isolator 5, a polarizer 6, a laser beam expander 7, a cylindrical lens 8, a slab crystal 9, and a heat dissipation device. Figure 1 Not shown in the image, see reference. Figure 5 19), pump mirror 10, quarter-wave plate 11, third reflecting mirror 12, first pump coupler 13, second pump coupler 14, first pump source 15, and second pump source 16.

[0042] Among them, the convex lens 2 is used to collimate the laser generated by the seed source 1;

[0043] The first reflecting mirror 3 and the second reflecting mirror 4 are used to change the direction of laser transmission.

[0044] Optical isolator 5 is used to isolate the laser after power amplification;

[0045] Polarizer 6 is used to transmit horizontally polarized laser light and reflect vertically polarized laser light.

[0046] Laser beam expander 7, used to increase the diameter of the laser beam;

[0047] Cylindrical lens 8, used to focus laser light in a single direction;

[0048] Slab crystal 9, used to amplify laser power;

[0049] A heat dissipation device is used to clamp the slab crystal 9 and cool the slab crystal 9.

[0050] Pump mirror 10 is used to transmit pump light and reflect laser light;

[0051] A quarter-wave plate 11 is used to change the polarization state of the laser.

[0052] The third reflecting mirror 12 is used to reflect laser light;

[0053] The first pump coupler 13 is used to focus the pump light generated by the first pump source 15 onto the slab crystal 9 to amplify the laser power;

[0054] The second pump coupler 14 is located on the side of the slab crystal 9 and the distance between it and the slab crystal 9 is adjustable. It is used to adjust the heat distribution in the slab crystal 9 based on the pump light generated by the second pump source 16, that is, to improve the beam quality by optimizing the laser divergence angle.

[0055] Seed source 1, convex lens 2, first reflecting mirror 3, second reflecting mirror 4, optical isolator 5, polarizer 6, laser beam expander 7, cylindrical lens 8, slab crystal 9, pump mirror 10, quarter wave plate 11 and third reflecting mirror 12 are arranged sequentially along the optical path.

[0056] In practical application scenarios, Figure 1 The positions of the optical isolator 5 and polarizer 6 can be interchanged. Specifically, the seed source 1, convex lens 2, first reflector 3, second reflector 4, polarizer 6, optical isolator 5, laser beam expander 7, cylindrical lens 8, slab crystal 9, pump mirror 10, quarter-wave plate 11, and third reflector 12 are arranged sequentially along the optical path. The optical isolator 5 requires linearly polarized light input. When polarizer 6 is located between the optical isolator 5 and the seed source 1, it can provide stable linearly polarized light. Furthermore, this arrangement effectively prevents interference from reverse light to the mode-locked laser.

[0057] However, when the polarizer 6 is located between the optical isolator 5 and the seed source 1, the high-power laser will pass through the optical components inside the optical isolator 5, posing a risk of damage to the devices. Figure 1 The device layout shown allows polarizer 6 to guide high-power laser output, thus achieving high-power laser output while avoiding damage to expensive components and increasing the lifespan of the laser amplifier.

[0058] In this embodiment, pump light is injected into the slab crystal 9 from the side using a second pump coupler 14. By changing the distance between the second pump coupler 14 and the slab crystal 9, the position of the pump light within the slab crystal 9 is adjusted, thereby adjusting the heat distribution within the slab crystal 9, correcting the distortion of the light spot after power amplification, and improving the quality of the amplified laser. In this embodiment, the second pump coupler 14 is located on either side of the slab crystal 9.

[0059] In one embodiment of this application, the seed source 1 can be a mode-locked laser for generating femtosecond or picosecond lasers, or it can be an optical parametric oscillator, etc.

[0060] In one embodiment of this application, the laser emitted by the slab crystal 9 is linearly polarized light, such as Nd:YVO4, Yb:KYW, Yb:KGW, etc.

[0061] The above-described optical path layout has the following advantages for slab crystals whose radiated laser light is in a linear polarization state:

[0062] First, the laser beam is incident on the laser crystal in a linear polarization state. The laser's polarization state coincides with the high-gain polarization state of the slab crystal 9, which is beneficial for increasing the laser's amplification power. After the first amplification, the linearly polarized laser beam is transformed into a circularly polarized state after passing through the quarter-wave plate 11. Subsequently, after being reflected by the third reflecting mirror 12, the laser beam returns along its original path. After passing through the quarter-wave plate 11 again, the circularly polarized state returns to the linear polarization state. Then, after passing through the slab crystal 9, the laser's polarization state coincides with the high-gain polarization state of the slab crystal 9, thus undergoing a second laser power amplification.

[0063] Secondly, after being amplified twice, the laser first passes through polarizer 6 for output, avoiding the laser from passing through optical isolator 5 again, thus reducing the risk of damage to optical isolator 5.

[0064] In one embodiment of this application, in order to further adjust the heat distribution within the lath crystal 9 and calibrate the distortion of the light spot after power amplification, such as... Figure 2 As shown, the laser amplifier also includes a third pump coupler 17 and a third pump source 18. In other words, pump couplers and pump sources are provided on both sides of the slab crystal 9 to further improve the quality of the output laser.

[0065] The second pump coupler 14 and the third pump coupler 17 are located on both sides of the slab crystal 9; the distance between the third pump coupler 17 and the slab crystal 9 is adjustable, and is used to adjust the heat distribution in the slab crystal 9 based on the pump light generated by the third pump source 18.

[0066] Taking a seed source as a mode-locked laser, a first and second reflecting mirror as 45° reflecting mirrors, and a third reflecting mirror as a total reflection mirror as an example, the working process of the laser amplifier is explained in detail.

[0067] like Figure 2 As shown, mode-locked laser 1 generates picosecond or femtosecond laser light. After passing through convex lens 2, the divergence angle of the laser beam is compressed, and the laser beam becomes parallel light. The laser light is reflected by two 45° mirrors and enters optical isolator 5. The laser light output from optical isolator 5 is then transmitted to polarizer 6. Polarizer 6 transmits the horizontally polarized laser light, and laser beam expander 7 expands the laser beam, increasing the beam diameter by a factor of two. Cylindrical lens 8 focuses the laser beam in the Y direction, resulting in an elliptical laser beam. The major axis of this elliptical laser beam is located in the X direction, and the minor axis is located in the Y direction. The minimum value of the focused elliptical laser beam in the Y direction, i.e., the focal point, is located within the slab crystal 9. Compared to a conventional bulk crystal, the beam spot length in the X direction within the crystal increases by 5-10 times.

[0068] The first pump coupler 13 outputs an elliptical pump beam with its major axis in the X direction and its minor axis in the Y direction. After passing through the pump mirror 10, the pump beam is focused into the slab crystal 9. The slab crystal 9 absorbs and temporarily stores the power of the pump beam. When the focal point of the laser beam meets the pump beam in the slab crystal, the laser beam extracts the power stored in the slab crystal, completing the first power amplification of the laser. Assuming that the stress on the slab crystal is uniform within the heat dissipation device, ensuring uniform heat dissipation, the laser beam spot after power amplification by the slab crystal will exhibit a uniform elliptical shape, such as... Figure 3 As shown.

[0069] However, since the length of slab crystals is typically 5-10 times that of conventional crystals, the clamping force of the heat dissipation device on the slab crystal is usually uneven due to differences in crystal size (thickness inhomogeneity) and inhomogeneity of the heat dissipation device (machining precision deviation of the heat dissipation device). This results in differences in heat exchange efficiency between the edges and center of the slab crystal and the heat dissipation device, thus affecting crystal heat dissipation. Under these conditions, the laser beam will be distorted after power amplification through the slab crystal, such as... Figure 4 As shown, the height of the left side of the elliptical light spot is significantly greater than that of the right side, indicating that the divergence on both sides of the light spot is inconsistent.

[0070] Therefore, in this embodiment, the pump light generated by the second pump coupler 14 and the third pump coupler 17 is injected into the slab crystal 9 from the side. By moving the second pump coupler 14 and the third pump coupler 17 to change their distance from the slab crystal 9, the position of the pump light within the slab crystal 9 is adjusted, thereby adjusting the heat distribution within the slab crystal 9 and calibrating the distortion of the laser spot after power amplification. Figure 5 As shown, the distorted spot before calibration is represented by a solid elliptical spot, and the calibrated spot is represented by a dashed elliptical spot. The heat dissipation device 19 consists of upper and lower layers, used to dissipate heat from the slab crystal 9 via cooling water or other means, thereby controlling the temperature of the slab crystal 9.

[0071] After the laser beam undergoes its first power amplification, it is transmitted to the pump mirror 10. Reflected by the pump mirror 10, the laser beam passes through the quarter-wave plate 11, which alters the polarization state of the laser beam. The incident laser beam is horizontally polarized, while the beam output from the quarter-wave plate 11 is circularly polarized. The circularly polarized laser beam is then reflected by the total reflection mirror 12 and returns to the quarter-wave plate 11. After exiting the quarter-wave plate 11, the laser beam's polarization changes from circular to vertical.

[0072] After being reflected by the pump mirror 10, the laser beam enters the slab crystal 9 again. In the slab crystal 9, the laser beam encounters the pump light again, and the laser beam extracts the power stored in the slab crystal 9 again, completing the second power amplification of the laser.

[0073] After the laser is amplified twice, it passes through polarizer 6. The amplified laser light is then reflected by polarizer 6 and output from the laser amplifier.

[0074] To accommodate the characteristics of different types of lath crystals, the position of the quarter-wave plate 11 can be adjusted. For example... Figure 6 As shown, this application embodiment provides a laser amplifier, including: a seed source 1, a convex lens 2, a first reflecting mirror 3, a second reflecting mirror 4, an optical isolator 5, a polarizer 6, a laser beam expander 7, a cylindrical lens 8, a slab crystal 9, and a heat dissipation device. Figure 6 Not shown in the image, please refer to the following: Figure 5 ), pump mirror 10, quarter-wave plate 11, third reflecting mirror 12, first pump coupler 13, second pump coupler 14, first pump source 15, and second pump source 16.

[0075] Among them, the convex lens 2 is used to collimate the laser generated by the seed source 1;

[0076] The first reflecting mirror 3 and the second reflecting mirror 4 are used to change the direction of laser transmission.

[0077] Optical isolator 5 is used to isolate the laser after power amplification;

[0078] Polarizer 6 is used to transmit horizontally polarized laser light and reflect vertically polarized laser light.

[0079] Laser beam expander 7, used to increase the diameter of the laser beam;

[0080] Cylindrical lens 8, used to focus laser light in a single direction;

[0081] Slab crystal 9, used to amplify laser power;

[0082] A heat dissipation device is used to clamp the slab crystal 9 and cool the slab crystal 9.

[0083] Pump mirror 10 is used to transmit pump light and reflect laser light;

[0084] A quarter-wave plate 11 is used to change the polarization state of the laser.

[0085] The third reflecting mirror 12 is used to reflect laser light;

[0086] The first pump coupler 13 is used to focus the pump light generated by the first pump source 15 onto the slab crystal 9 to amplify the laser power;

[0087] The second pump coupler 14 is located on the side of the slab crystal 9 and the distance between it and the slab crystal 9 is adjustable. It is used to adjust the heat distribution in the slab crystal 9 based on the pump light generated by the second pump source 16, that is, to improve the beam quality by optimizing the laser divergence angle.

[0088] Seed source 1, convex lens 2, first reflecting mirror 3, second reflecting mirror 4, optical isolator 5, polarizer 6, laser beam expander 7, cylindrical lens 8, quarter-wave plate 11, slab crystal 9, pump mirror 10, and third reflecting mirror 12 are arranged sequentially along the optical path direction; or, seed source 1, convex lens 2, first reflecting mirror 3, second reflecting mirror 4, polarizer 6, optical isolator 5, laser beam expander 7, cylindrical lens 8, quarter-wave plate 11, slab crystal 9, pump mirror 10, and third reflecting mirror 12 are arranged sequentially along the optical path direction.

[0089] Similar to the aforementioned embodiments, the positions of the optical isolator 5 and the polarizer 6 can be interchanged, and the specific reasons will not be repeated here.

[0090] In this embodiment, pump light is injected into the slab crystal 9 from the side using a second pump coupler 14. The position of the pump light within the slab crystal 9 is adjusted by changing the distance between the second pump coupler 14 and the slab crystal 9, thereby adjusting the heat distribution within the slab crystal 9, calibrating the distortion of the light spot after power amplification, and improving the quality of the amplified laser.

[0091] Although Figure 1 and Figure 2 The corresponding layout scheme is applicable to lath crystals where the radiated laser is linearly polarized, as well as to other crystals such as isotropic crystals.

[0092] However, for isotropic crystals, such as Yb:YAG and Nd:YAG, if... Figure 1 The scheme shown might cause polarization state degradation of the laser during high-power amplification. Therefore, in this embodiment, a quarter-wave plate 11 is used to convert the laser's polarization state from linear to circular before amplification. Then, after a second amplification, the laser passes through the quarter-wave plate 11 again, and the circular polarization state is converted back to linear polarization. This amplification method suppresses polarization state degradation during amplification. Therefore, for isotropic crystals, Figure 6 The proposed solution is more suitable. Of course, Figure 6 and Figure 7 The corresponding layout scheme can also be applied to slab crystals or other crystals where the radiated laser is in a linear polarization state.

[0093] Similar to the aforementioned embodiments, seed source 1 can be a mode-locked laser used to generate picosecond or femtosecond lasers. The first reflector 3 is a 45° reflector, the second reflector 4 is a 45° reflector, and the third reflector 12 is a total reflection mirror. It should be noted that the angles of the reflectors involved in the various embodiments of this application can be adjusted according to the actual application scenario. For example, the total reflection mirror can be replaced with a 6° reflector, and the angles of the first and second reflectors can both be 40°. This is not limited to a single implementation method.

[0094] Similar to the aforementioned embodiments, in one embodiment of this application, the laser amplifier may further include a third pump coupler 17 and a third pump source 18. That is, in order to optimize the output laser quality, pump couplers are provided on both sides.

[0095] The second pump coupler 14 and the third pump coupler 17 are located on both sides of the slab crystal 9; the distance between the third pump coupler 17 and the slab crystal 9 is adjustable, and is used to adjust the heat distribution in the slab crystal 9 based on the pump light generated by the third pump source 18.

[0096] Compared to conventional bulk crystals, the various embodiments of this application use slab crystals combined with pump couplers to achieve high-power, high-beam-quality laser amplification.

[0097] First, using a large-area, flat slab crystal can achieve higher power pumping, thereby obtaining higher laser power output.

[0098] Secondly, the first pump coupler is combined with the second and third pump couplers. Usually, the power of the second and third pump couplers is less than that of the first pump coupler. That is, high-power laser output can be achieved by using high-power pumping as the main method and low-power pumping as the auxiliary method. Low-power pumping (second and third pump couplers) can also be used to optimize the beam distortion and improve the laser beam quality.

[0099] Finally, the optimized and reasonable layout of devices such as polarizers and isolators allows the laser to be output without passing through conventional isolators after high-power amplification. This effectively prevents high-power lasers from damaging valuable isolators, increases the lifespan of high-power amplifiers, reduces laser maintenance costs, and achieves the goal of cost reduction and efficiency improvement.

[0100] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can occur depending on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A laser amplifier, characterized by, include: Seed source, convex lens, first reflecting mirror, second reflecting mirror, optical isolator, polarizer, laser beam expander, cylindrical lens, slab crystal, heat dissipation device, pump mirror, quarter-wave plate, third reflecting mirror, first pump coupler, second pump coupler, first pump source and second pump source; The convex lens is used to collimate the laser generated by the seed source; the first and second reflecting mirrors are used to change the laser transmission direction; the optical isolator is used to isolate the amplified laser; the polarizer is used to transmit horizontally polarized laser and reflect vertically polarized laser; the laser beam expander is used to increase the laser spot diameter; the cylindrical lens is used to focus the laser in a single direction; the slab crystal is used to amplify the laser power; the heat dissipation device is used to clamp and cool the slab crystal; the pump mirror is used to transmit pump light and reflect laser; the 1 / A waveplate is used to change the polarization state of the laser; a third mirror is used to reflect the laser; a first pump coupler is used to focus the pump light generated by the first pump source onto the slab crystal to amplify the laser power; a second pump coupler is located on the side of the slab crystal, and the distance between the second pump coupler and the slab crystal is adjustable. It is used to adjust the heat distribution within the slab crystal based on the pump light generated by the second pump source, and to calibrate the distortion of the laser spot after power amplification. The distortion is caused by the uneven distribution of stress within the slab crystal, resulting in different laser divergence angles at different positions after laser amplification. The seed source, the convex lens, the first reflector, the second reflector, the optical isolator, the polarizer, the laser beam expander, the cylindrical lens, the slab crystal, the pump mirror, the quarter-wave plate, and the third reflector are arranged sequentially along the optical path; or, the seed source, the convex lens, the first reflector, the second reflector, the polarizer, the optical isolator, the laser beam expander, the cylindrical lens, the slab crystal, the pump mirror, the quarter-wave plate, and the third reflector are arranged sequentially along the optical path. The power of the second pump coupler is less than that of the first pump coupler.

2. The laser amplifier as described in claim 1, characterized in that, in, The laser emitted by the lath crystal is linearly polarized light.

3. The laser amplifier of claim 1, wherein, Further includes: a third pump coupler and a third pump source; The second pump coupler and the third pump coupler are located on opposite sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and it is used to adjust the heat distribution within the slab crystal based on the pump light generated by the third pump source.

4. The laser amplifier of claim 1, wherein in, The seed source is a mode-locked laser used to generate picosecond or femtosecond lasers.

5. The laser amplifier of claim 1, wherein in, The first reflector is a 45° reflector, the second reflector is a 45° reflector, and the third reflector is a total reflection mirror.

6. A laser amplifier, characterized by, include: Seed source, convex lens, first reflecting mirror, second reflecting mirror, optical isolator, polarizer, laser beam expander, cylindrical lens, slab crystal, heat dissipation device, pump mirror, quarter-wave plate, third reflecting mirror, first pump coupler, second pump coupler, first pump source and second pump source; The convex lens is used to collimate the laser generated by the seed source; the first and second reflecting mirrors are used to change the laser transmission direction; the optical isolator is used to isolate the amplified laser; the polarizer is used to transmit horizontally polarized laser and reflect vertically polarized laser; the laser beam expander is used to increase the laser spot diameter; the cylindrical lens is used to focus the laser in a single direction; the slab crystal is used to amplify the laser power; the heat dissipation device is used to clamp and cool the slab crystal; the pump mirror is used to transmit pump light and reflect laser; the 1 / A waveplate is used to change the polarization state of the laser; a third mirror is used to reflect the laser; a first pump coupler is used to focus the pump light generated by the first pump source onto the slab crystal to amplify the laser power; a second pump coupler is located on the side of the slab crystal, and the distance between the second pump coupler and the slab crystal is adjustable. It is used to adjust the heat distribution within the slab crystal based on the pump light generated by the second pump source, and to calibrate the distortion of the laser spot after power amplification. The distortion is caused by the uneven distribution of stress within the slab crystal, resulting in different laser divergence angles at different positions after laser amplification. The seed source, the convex lens, the first reflector, the second reflector, the optical isolator, the polarizer, the laser beam expander, the cylindrical lens, the quarter-wave plate, the slab crystal, the pump mirror, and the third reflector are arranged sequentially along the optical path; or, the seed source, the convex lens, the first reflector, the second reflector, the polarizer, the optical isolator, the laser beam expander, the cylindrical lens, the quarter-wave plate, the slab crystal, the pump mirror, and the third reflector are arranged sequentially along the optical path. The power of the second pump coupler is less than that of the first pump coupler.

7. The laser amplifier of claim 6, wherein, in, The lath crystals are isotropic.

8. The laser amplifier as described in claim 6, characterized in that, Further includes: a third pump coupler and a third pump source; The second pump coupler and the third pump coupler are located on opposite sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and it is used to adjust the heat distribution within the slab crystal based on the pump light generated by the third pump source.

9. The laser amplifier of claim 6, wherein in, The seed source is a mode-locked laser used to generate picosecond or femtosecond lasers.

10. The laser amplifier of claim 6, wherein, in, The first reflector is a 45° reflector, the second reflector is a 45° reflector, and the third reflector is a total reflection mirror.

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