Laser amplifier

Abstract

The invention discloses a laser amplifier, which relates to the technical field of lasers and comprises a seed source, a convex lens, a first reflecting mirror, a second reflecting mirror, an optical isolator, a polarizing film, a laser beam expanding mirror, a cylindrical lens, a lath crystal, a heat dissipation device, a pumping mirror, a 1 / 4 wave plate, a third reflecting mirror, a first pumping coupler, a second pumping coupler, a first pumping source and a second pumping source. The first pumping coupler is used for focusing the pumping light generated by the first pumping source on the slab crystal so as to amplify the laser power; the second pumping coupler is located on the side face of the lath crystal, the distance between the second pumping coupler and the lath crystal is adjustable, and the second pumping coupler is used for adjusting heat distribution in the lath crystal based on pumping light generated by the second pumping source. According to the invention, the energy and beam quality of the amplified laser can be improved.

Description

Technical Field

[0001] The present application relates to the field of laser technology, and in particular to a laser amplifier. Background Art

[0002] High-power lasers are widely used in industrial processing, aerospace and other fields. In actual application scenarios, due to problems such as damage to optical devices and deterioration of spot quality, the laser power generated by the seed source cannot meet business needs. Therefore, it is necessary to further increase the laser power through a laser amplifier.

[0003] In order to increase the laser power, existing laser amplifiers usually use slab crystals as laser crystals. The laser crystals are flat and usually 5-10 times longer in the X direction than conventional block crystals. The increase in crystal volume can achieve higher-power pumping, thereby providing higher-power amplification for the laser. However, when large-sized laser crystals are clamped in a heat sink, uneven stress will be introduced due to the increase in size, resulting in different laser divergence angles at different positions after laser amplification, laser distortion, and reduced beam quality of the amplified laser. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a laser amplifier that can improve the energy and beam quality of the amplified laser.

[0005] In a first aspect, an embodiment of the present application provides a laser amplifier, comprising: a seed source, a convex lens, a first reflector, a second reflector, an optical isolator, a polarizer, a laser beam expander, a cylindrical lens, a slab crystal, a heat sink, a pump mirror, a quarter wave plate, a third reflector, a first pump coupler, a second pump coupler, a first pump source, and a second pump source; Among them, the convex lens is used to collimate the laser generated by the seed source; the first reflector and the second reflector are used to change the transmission direction of the laser; the optical isolator is used to isolate the laser after power amplification; the polarizer is used to transmit the horizontally polarized laser and reflect the vertically polarized laser; the laser beam expander is used to increase the spot diameter of the laser; 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 sink is used to clamp the slab crystal and cool the slab crystal; the pump mirror is used to transmit the pump light and reflect the laser; the 1 / 4 wave plate is used to change the polarization state of the laser; the third reflector is used to reflect the laser; the first pump coupler is used to focus the pump light generated by the first pump source on the slab crystal to amplify the laser power; the second pump coupler is located on the side of the slab crystal, and the distance from the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the second pump source; 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 in sequence along the light 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 in sequence along the light path.

[0006] Optionally, Wherein, the laser radiated by the slab crystal is linearly polarized light.

[0007] Optionally, further comprising: a third pump coupler and a third pump source; The second pump coupler and the third pump coupler are located on both sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the third pump source.

[0008] Optionally, Wherein, the seed source is a mode-locked laser, which is used to generate picosecond or femtosecond laser.

[0009] Optionally, Among them, the first reflector is a 45° reflector, the second reflector is a 45° reflector, and the third reflector is a total reflector.

[0010] In a second aspect, an embodiment of the present application provides a laser amplifier, comprising: a seed source, a convex lens, a first reflector, a second reflector, an optical isolator, a polarizer, a laser beam expander, a cylindrical lens, a slab crystal, a heat sink, a pump mirror, a quarter wave plate, a third reflector, a first pump coupler, a second pump coupler, a first pump source, and a second pump source; Among them, the convex lens is used to collimate the laser generated by the seed source; the first reflector and the second reflector are used to change the transmission direction of the laser; the optical isolator is used to isolate the laser after power amplification; the polarizer is used to transmit the horizontally polarized laser and reflect the vertically polarized laser; the laser beam expander is used to increase the spot diameter of the laser; 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 sink is used to clamp the slab crystal and cool the slab crystal; the pump mirror is used to transmit the pump light and reflect the laser; the 1 / 4 wave plate is used to change the polarization state of the laser; the third reflector is used to reflect the laser; the first pump coupler is used to focus the pump light generated by the first pump source on the slab crystal to amplify the laser power; the second pump coupler is located on the side of the slab crystal, and the distance from the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the second pump source; 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 in sequence along the light 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 in sequence along the light path.

[0011] Optionally, Wherein, the lath crystals are isotropic.

[0012] Optionally, further comprising: a third pump coupler and a third pump source; The second pump coupler and the third pump coupler are located on both sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the third pump source.

[0013] Optionally, Wherein, the seed source is a mode-locked laser, which is used to generate picosecond or femtosecond laser.

[0014] Optionally, Among them, the first reflector is a 45° reflector, the second reflector is a 45° reflector, and the third reflector is a total reflector.

[0015] An 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 laser after amplification.

[0016] The further effects of the above-mentioned non-conventional optional manner will be described below in conjunction with the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to better understand the present application and do not constitute an improper limitation on the present application. Figure 1 is a schematic diagram of a laser amplifier provided by an embodiment of the present application; Figure 2 is a schematic diagram of a laser amplifier provided by another embodiment of the present application; Figure 3 is a schematic diagram of a light spot presenting a uniform elliptical shape provided by an embodiment of the present application; Figure 4 is a schematic diagram of a distorted light spot provided by an embodiment of the present application; Figure 5 is a schematic diagram comparing light spots before and after optimization provided by an embodiment of the present application; Figure 6 is a schematic diagram of a laser amplifier provided in yet another embodiment of the present application; Figure 7 This is a schematic diagram of a laser amplifier provided in yet another embodiment of the present application. DETAILED DESCRIPTION

[0018] The following is a description of exemplary embodiments of the present application in conjunction with the accompanying drawings, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0019] Small-sized block laser crystals under high-power pumping conditions will reduce the beam quality after laser power amplification, and will also increase the risk of crystal damage. In order to increase laser power, high-power pump light is usually used to pump larger-sized laser crystals. The laser crystals are flat, and the crystal length in the X direction is usually 5-10 times that of conventional crystals. The increase in crystal volume can achieve higher-power pumping, thereby providing higher-power amplification for the laser. However, when large-sized laser crystals are installed and clamped in metal heat sinks, uneven stress is usually introduced due to the increase in crystal size. The uneven distribution of stress in the crystal will cause different laser divergence angles at different positions after laser amplification, resulting in beam distortion and reduced beam quality.

[0020] In view of this, if Figure 1 As shown, the embodiment of the present application provides a laser amplifier, including: a seed source 1, a convex lens 2, a first reflector 3, a second reflector 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, refer to Figure 5 19), a pump mirror 10, a quarter wave plate 11, a third reflector 12, a first pump coupler 13, a second pump coupler 14, a first pump source 15 and a second pump source 16.

[0021] Wherein, the convex lens 2 is used to collimate the laser generated by the seed source 1; The first reflector 3 and the second reflector 4 are used to change the transmission direction of the laser; An optical isolator 5, used to isolate the laser after power amplification; Polarizer 6, used for transmitting horizontally polarized laser light and reflecting vertically polarized laser light; Laser beam expander 7, used to increase the spot diameter of the laser; A cylindrical lens 8, used to focus the laser light in a single direction; Slab crystal 9, used to amplify laser power; A heat sink, used for clamping the lath crystal 9 and cooling the lath crystal 9; A pump mirror 10, used to transmit pump light and reflect laser light; A quarter wave plate 11, used for changing the polarization state of the laser; A third reflecting mirror 12, used for reflecting laser light; a first pump coupler 13, for focusing the pump light generated by the first pump source 15 onto the slab crystal 9 to amplify the laser power; The second pump coupler 14 is located on the side of the slab crystal 9, and the distance between the second pump coupler 14 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 second pump source 16, that is, to improve the beam quality by optimizing the laser divergence angle; The seed source 1, convex lens 2, first reflector 3, second reflector 4, optical isolator 5, polarizer 6, laser beam expander 7, cylindrical lens 8, slab crystal 9, pump mirror 10, 1 / 4 wave plate 11 and third reflector 12 are arranged in sequence along the optical path direction.

[0022] In actual application scenarios, Figure 1 The positions of the optical isolator 5 and the polarizer 6 can be swapped, that is, the seed source 1, the convex lens 2, the first reflector 3, the second reflector 4, the polarizer 6, the optical isolator 5, the laser beam expander 7, the cylindrical lens 8, the slab crystal 9, the pump mirror 10, the 1 / 4 wave plate 11 and the third reflector 12 are arranged in sequence along the optical path. The optical isolator 5 requires linearly polarized light input. When the polarizer 6 is located between the optical isolator 5 and the seed source 1, the polarizer 6 can provide stable linearly polarized light. In addition, this layout can effectively prevent the interference of reverse light on the mode-locked laser.

[0023] 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, which may damage the components. Figure 1 The device layout shown enables the polarizer 6 to output high-power laser light, thus achieving high-power laser output and avoiding damage to expensive devices, thereby increasing the service life of the laser amplifier.

[0024] In the embodiment of the present application, the pump light is injected into the slab crystal 9 from the side of the slab crystal 9 through the second pump coupler 14, and the position of the pump light in 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 in the slab crystal 9, calibrating the distortion of the light spot after power amplification, and improving the quality of the laser after amplification. The second pump coupler 14 in this embodiment is located on any side of the slab crystal 9.

[0025] In one embodiment of the present application, the seed source 1 may be a mode-locked laser for generating femtosecond or picosecond laser, or may be an optical parametric oscillator, etc.

[0026] In one embodiment of the present application, the laser radiated by the slab crystal 9 is linearly polarized light, such as Nd:YVO4, Yb:KYW, Yb:KGW, etc.

[0027] The above optical path layout for slab crystals with linearly polarized laser radiation has the following advantages: First, the laser is incident on the laser crystal in a linear polarization state, and the polarization state of the laser coincides with the polarization state of the slab crystal 9 with a higher gain, which is beneficial to improving the amplification power of the laser. After the first amplification, the laser in the linear polarization state is converted into a circular polarization state after passing through the 1 / 4 wave plate 11, and then the laser returns along the original path after being reflected by the third reflector 12. In this way, the circular polarization state is restored to a linear polarization state after passing through the 1 / 4 wave plate 11 again, and then passes through the slab crystal 9, and the polarization state of the laser coincides with the polarization state of the slab crystal 9 with a high gain, thus undergoing the second laser power amplification.

[0028] Secondly, after the laser light has been power amplified twice, it is first output through the polarizer 6 to prevent the laser light from passing through the optical isolator 5 again, thereby reducing the risk of damage to the optical isolator 5 .

[0029] In one embodiment of the present application, in order to further adjust the heat distribution in the slab crystal 9, the distortion of the light spot after power amplification is calibrated, such as Figure 2 As shown, the laser amplifier further 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, further improving the quality of the output laser.

[0030] 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 .

[0031] Taking the seed source as a mode-locked laser, the first reflector and the second reflector as 45° reflectors, and the third reflector as a full reflector as an example, the working process of the laser amplifier is described in detail.

[0032] like Figure 2 As shown, the mode-locked laser 1 generates picosecond or femtosecond lasers. After the generated laser passes through the convex lens 2, the divergence angle of the laser beam is compressed, and the laser beam is converted into parallel light transmission. The laser is reflected by two 45° reflectors and enters the optical isolator 5. The laser output by the optical isolator 5 is then transmitted to the polarizer 6. The polarizer 6 transmits the horizontally polarized laser, and the laser beam expander 7 expands the laser beam. The spot diameter after beam expansion increases exponentially. The cylindrical lens 8 focuses the laser beam in the Y direction, and the focused laser beam is elliptical. The major axis of the elliptical laser beam is in the X direction, and the minor axis is in the Y direction. The minimum value of the elliptical laser beam in the Y direction after focusing, that is, the focus is located in the lath crystal 9. Compared with conventional block crystals, the spot length of the laser beam in the X direction in the crystal will increase by 5-10 times.

[0033] The first pump coupler 13 outputs an elliptical pump light, the major axis of which is in the X direction and the minor axis in the Y direction. After passing through the pump mirror 10, the pump light is focused in the slab crystal 9, which absorbs the power of the pump light and temporarily stores the absorbed power. After the focus of the laser beam meets the pump light 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 of the slab crystal is uniform when clamped in the heat sink, and uniform heat dissipation can be maintained, the laser spot presents a uniform ellipse after the power amplification of the slab crystal, as shown in FIG. Figure 3 shown.

[0034] However, since the length of the slab crystal is usually 5-10 times that of the conventional crystal, the clamping force of the heat sink on the slab crystal is usually uneven due to the size difference of the crystal (non-uniformity of thickness) and the non-uniformity of the heat sink (deviation of the processing accuracy of the heat sink). There is a difference in the heat exchange efficiency between the edge and center of the slab crystal and the heat sink, which affects the heat dissipation of the crystal. In this state, the laser spot will be distorted after the power amplification of the slab crystal, such as Figure 4 As shown, the spot height of the left part of the elliptical spot is obviously greater than that of the right part, that is, the divergence degree of the two sides of the spot is inconsistent.

[0035] In view of this, the embodiment of the present application injects the pump light generated by the second pump coupler 14 and the third pump coupler 17 into the slab crystal 9 from the side of the slab crystal 9, and adjusts the position of the pump light in the slab crystal 9 by moving the second pump coupler 14 and the third pump coupler 17 to change the distance from the slab crystal 9, thereby adjusting the heat distribution in the slab crystal 9 and calibrating the distortion of the light spot after the laser power is amplified. Figure 5 As shown, the distorted light spot before calibration is shown as a solid line elliptical light spot, and the light spot after calibration is shown as a dotted line elliptical light spot. The heat sink 19 is divided into two layers, upper and lower, for dissipating heat from the slab crystal 9 by cooling water or the like, and controlling the temperature of the slab crystal 9.

[0036] After the laser beam completes the first power amplification, it is transmitted to the pump mirror 10. After being reflected by the pump mirror 10, the laser beam passes through the 1 / 4 wave plate 11. The 1 / 4 wave plate 11 can change the polarization state of the laser beam. The polarization state of the laser beam incident on the 1 / 4 wave plate 11 is horizontal polarization state, and the polarization state of the laser beam output from the 1 / 4 wave plate 11 becomes circular polarization state. The circularly polarized laser beam is reflected by the total reflection mirror 12 and returns to the 1 / 4 wave plate 11 again. After the laser beam is output from the 1 / 4 wave plate 11, the polarization state changes from circular polarization to vertical polarization.

[0037] The laser beam is reflected by the pump mirror 10 again and enters the slab crystal 9. In the slab crystal 9, the laser beam meets the pump light again. The laser beam extracts the power stored in the slab crystal 9 again, completing the second power amplification of the laser.

[0038] After being amplified twice, the laser passes through the polarizer 6. At this time, the amplified laser light is reflected by the polarizer 6 and output from the laser amplifier.

[0039] In order to adapt to the characteristics of different types of slat crystals, the position of the quarter wave plate 11 can be adjusted. Figure 6 As shown, the embodiment of the present application provides a laser amplifier, including: a seed source 1, a convex lens 2, a first reflector 3, a second reflector 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, please refer to Figure 5 ), a pump mirror 10, a quarter wave plate 11, a third reflecting mirror 12, a first pump coupler 13, a second pump coupler 14, a first pump source 15 and a second pump source 16.

[0040] Wherein, the convex lens 2 is used to collimate the laser generated by the seed source 1; The first reflector 3 and the second reflector 4 are used to change the transmission direction of the laser; An optical isolator 5, used to isolate the laser after power amplification; Polarizer 6, used for transmitting horizontally polarized laser light and reflecting vertically polarized laser light; Laser beam expander 7, used to increase the spot diameter of the laser; A cylindrical lens 8, used to focus the laser light in a single direction; Slab crystal 9, used to amplify laser power; A heat sink, used for clamping the lath crystal 9 and cooling the lath crystal 9; A pump mirror 10, used to transmit pump light and reflect laser light; A quarter wave plate 11, used for changing the polarization state of the laser; A third reflecting mirror 12, used for reflecting laser light; a first pump coupler 13 for focusing the pump light generated by the first pump source 15 onto the slab crystal 9 to amplify the laser power; The second pump coupler 14 is located on the side of the slab crystal 9 and has an adjustable distance from the slab crystal 9. 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.

[0041] The seed source 1, the convex lens 2, the first reflector 3, the second reflector 4, the optical isolator 5, the polarizer 6, the laser beam expander 7, the cylindrical lens 8, the quarter wave plate 11, the slat crystal 9, the pump mirror 10 and the third reflector 12 are arranged in sequence along the optical path; or, the seed source 1, the convex lens 2, the first reflector 3, the second reflector 4, the polarizer 6, the optical isolator 5, the laser beam expander 7, the cylindrical lens 8, the quarter wave plate 11, the slat crystal 9, the pump mirror 10 and the third reflector 12 are arranged in sequence along the optical path.

[0042] Similar to the above-mentioned embodiment, the positions of the optical isolator 5 and the polarizer 6 can be swapped, and the specific reasons are not repeated here.

[0043] In the embodiment of the present application, the pump light is injected into the slab crystal from the side of the slab crystal 9 through the second pump coupler 14, and the position of the pump light in 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 in the slab crystal 9, calibrating the distortion of the light spot after power amplification, and improving the quality of the laser after amplification.

[0044] Although Figure 1 and Figure 2 The corresponding layout scheme is applicable to slab crystals whose radiated laser is in a linear polarization state, and is also applicable to other crystals such as isotropic crystals.

[0045] However, for isotropic crystals such as Yb:YAG, Nd:YAG, etc., if Figure 1 The scheme shown in the figure may cause the polarization state of the laser to degrade during the high-power amplification process. Therefore, the embodiment of the present application uses a quarter wave plate 11 to convert the polarization state of the laser from linear to circular polarization state before laser amplification, and then after the second amplification, the laser passes through the quarter wave plate 11 again, and the circular polarization state of the laser is converted to linear polarization state. This amplification method will suppress the polarization state degradation of the laser during the amplification process. Therefore, for isotropic crystals, Figure 6 The solution shown is more suitable. Of course, Figure 6 and Figure 7 The corresponding layout scheme can also be applied to slab crystals or other crystals that radiate laser light in a linear polarization state.

[0046] Similar to the above-mentioned embodiment, the seed source 1 can be a mode-locked laser for generating 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 reflector. It should be noted that the angles of the reflectors involved in the various embodiments of the present application can be adjusted according to the actual application scenario, such as replacing the total reflector with a 6° reflector, and the angles of the first reflector and the second reflector are both 40°, and are not limited to one implementation method.

[0047] Similar to the above-mentioned embodiment, in one embodiment of the present 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.

[0048] 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 .

[0049] Compared with conventional block crystals, various embodiments of the present application use slab crystals in combination with pump couplers, etc. to achieve high-power, high-beam-quality laser amplification.

[0050] First, the use of large-area, flat slab crystals can achieve higher-power pumping, thereby obtaining higher laser power output.

[0051] Secondly, the first pump coupler is combined with the second pump coupler and the third pump coupler. Usually, the power of the second pump coupler and the third pump coupler is smaller than that of the first pump coupler. That is, high-power laser output can be achieved by mainly using high-power pumping and supplemented by low-power pumping. Low-power pumping (the second pump coupler and the third pump coupler) can also be used to optimize the spot distortion and improve the laser beam quality.

[0052] Finally, the optimized and reasonable layout of components such as polarizers and isolators ensures that the laser can be output after high-power amplification without passing through a conventional isolator, effectively preventing high-power lasers from damaging high-value isolators, increasing the service life of high-power amplifiers, and reducing laser maintenance costs, thereby achieving the goal of reducing costs and increasing efficiency.

[0053] The above specific implementations do not constitute a limitation on the protection scope of this application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may 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 in the protection scope of this application.

Claims

1. A laser amplifier, characterized in that: include: Seed source, convex lens, first reflector, second reflector, optical isolator, polarizer, 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; Among them, the convex lens is used to collimate the laser generated by the seed source; the first reflector and the second reflector are used to change the transmission direction of the laser; the optical isolator is used to isolate the laser after power amplification; the polarizer is used to transmit the horizontally polarized laser and reflect the vertically polarized laser; the laser beam expander is used to increase the spot diameter of the laser; 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 sink is used to clamp the slab crystal and cool the slab crystal; the pump mirror is used to transmit the pump light and reflect the laser; the 1 / 4 wave plate is used to change the polarization state of the laser; the third reflector is used to reflect the laser; the first pump coupler is used to focus the pump light generated by the first pump source on the slab crystal to amplify the laser power; the second pump coupler is located on the side of the slab crystal, and the distance from the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the second pump source; 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 in sequence along the light 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 in sequence along the light path.

2. The laser amplifier according to claim 1, wherein: in, The laser light radiated by the slab crystal is linearly polarized light.

3. The laser amplifier according to claim 1, wherein: further comprising: a third pump coupler and a third pump source; The second pump coupler and the third pump coupler are located on both sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the third pump source.

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

5. The laser amplifier according to 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 reflector.

6. A laser amplifier, characterized in that: include: Seed source, convex lens, first reflector, second reflector, optical isolator, polarizer, 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; Among them, the convex lens is used to collimate the laser generated by the seed source; the first reflector and the second reflector are used to change the transmission direction of the laser; the optical isolator is used to isolate the laser after power amplification; the polarizer is used to transmit the horizontally polarized laser and reflect the vertically polarized laser; the laser beam expander is used to increase the spot diameter of the laser; 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 sink is used to clamp the slab crystal and cool the slab crystal; the pump mirror is used to transmit the pump light and reflect the laser; the 1 / 4 wave plate is used to change the polarization state of the laser; the third reflector is used to reflect the laser; the first pump coupler is used to focus the pump light generated by the first pump source on the slab crystal to amplify the laser power; the second pump coupler is located on the side of the slab crystal, and the distance from the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the second pump source; 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 in sequence along the light 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 in sequence along the light path.

7. The laser amplifier according to claim 6, characterized in that in, The lath crystals are isotropic.

8. The laser amplifier according to claim 6, wherein: further comprising: a third pump coupler and a third pump source; The second pump coupler and the third pump coupler are located on both sides of the slab crystal; the distance between the third pump coupler and the slab crystal is adjustable, and is used to adjust the heat distribution in the slab crystal based on the pump light generated by the third pump source.

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

10. The laser amplifier according to 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 reflector.

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