Large-area pumping slab power amplifier module, laser amplifier and laser oscillator

Abstract

The utility model relates to the technical field of solid laser amplifiers, in particular to a large-surface pumping slab power amplifier module, a laser amplifier and a laser oscillator, which comprises a pumping source, a waveguide coupling module and a slab crystal module, the slab crystal module comprises a slab crystal, a water cooling device and a quartz window, the largest surface of the slab crystal is a pumping surface, and the water cooling device is arranged on the pumping surface. The large surface of the lath crystal serves as a pumping surface, the pumping surface is plated with a pumping light antireflection film and a laser high-reflective film, the secondary large surface of the lath crystal serves as a laser light-passing surface, the laser light-passing surface is plated with a seed light antireflection film and a laser antireflection film, and compared with the prior art, the output power of the laser amplifier is effectively improved through the technical scheme.

Description

Technical Field

[0001] This utility model relates to the field of solid-state laser amplifier technology, and in particular to a large-area pump slab power amplifier module, a laser amplifier, and a laser oscillator. Background Technology

[0002] In the field of solid-state lasers, laser shock peening technology requires the power density of the laser acting on the target to reach the order of GW / cm2, which requires solid-state lasers to have high laser output power and output stability.

[0003] Traditional methods for improving laser output power mainly include increasing the size and aperture of the laser gain medium and employing multi-stage amplification. However, simply increasing the size and aperture of the laser gain medium increases the difficulty of thermal management, reducing its heat dissipation effect, which in turn limits the laser's output power and stability, resulting in limited improvements in laser output power and stability. Regarding multi-stage amplification, the utility model patent with patent number CN208241075U discloses a picosecond laser two-way two-stage amplification device, which uses two laser crystals, a first laser crystal and a second laser crystal, to perform two-stage amplification technology, improving the amplification gain of the seed light. However, this type of laser crystal has light-transmitting end faces with a small aperture, low thermal management efficiency of the slab crystal in the thickness direction, and still low utilization of the gain medium, making it difficult to achieve high peak power density and high-energy single pulses.

[0004] Therefore, it is necessary to propose a large-area pumped slab power amplifier module, a laser amplifier, and a laser oscillator to improve the output power and output stability of the laser amplifier. Utility Model Content

[0005] The purpose of this invention is to solve the problem of low output power and output stability of existing laser equipment. It provides a large-area pump slab power amplifier module, a laser amplifier and a laser oscillator.

[0006] The technical solution of this utility model is:

[0007] A large-area pumped slab power amplifier module includes a pump source, a waveguide coupling module, and a slab crystal module. The slab crystal module includes a slab crystal, a water-cooling device, and a quartz window. The largest surface of the slab crystal is the pump surface, which is coated with a pump light antireflection film and a laser high reflectivity film. The second largest surface of the slab crystal is the laser light transmission surface, which is coated with a seed light antireflection film and a laser antireflection film. The pump surface and the laser light transmission surface are arranged facing each other.

[0008] Furthermore, the water cooling device is set on one side of the largest surface and one side of the second largest surface of the lath crystal. The quartz window is located on one side of the second largest surface of the lath crystal, and the water cooling device on this side is located between the quartz window and the lath crystal. The water cooling device is used to cool the crystal.

[0009] Furthermore, the cross-section of the lath crystal is trapezoidal or rectangular, and the end face and side face of the lath crystal have a wedge angle difference of 1-2 degrees. The surface is roughened to suppress the generation of amplified spontaneous emission (ASE) and parasitic oscillations.

[0010] Furthermore, the quartz window is coated with a seed laser antireflection film and a laser antireflection film on both sides, and the laser is output through the quartz window.

[0011] Furthermore, the pump source is a laser diode bar array, which provides the basis for high-power laser output.

[0012] Furthermore, the water cooling device has an inlet on one side and an outlet on the other side. The water flow channel inside the water cooling device contains capillary pores to ensure the laminar flow characteristics of the water cooling device and reduce the impact on pump uniformity and laser wavefront.

[0013] Furthermore, the waveguide coupling module and the slab crystal module are welded together to form a whole. The slab crystal is a laser crystal with thermal conductivity, which facilitates heat dissipation.

[0014] A large-area pumped slab laser amplifier, employing any of the above-mentioned large-area pumped slab power amplifier modules, further includes a seed source, a first shaping system, a total reflection mirror, a second shaping system, and a focusing lens. The first shaping system is located between the seed source and the total reflection mirror, and the second shaping system is located between the large-area pumped slab power amplifier module and the focusing lens.

[0015] Furthermore, the first shaping system includes a first negative lens, a first positive lens, a second negative lens, and a second positive lens arranged sequentially, and the second shaping system includes a third negative lens and a third positive lens, thereby expanding and shaping the seed laser to match the seed laser with the magnification stage spot pattern. The total reflection mirror is coated with a high-reflectivity film for reflecting the laser so that it enters the slab crystal module, and the focusing lens is coated with a laser anti-reflection film for focusing the magnified laser.

[0016] A large-area pumped slab laser oscillator, employing any of the above-mentioned large-area pumped slab power amplifier modules, further includes a first lens and a second lens, the first lens and the second lens being located on both sides of the large-area pumped slab power amplifier module.

[0017] This invention discloses a large-area pumped slab laser amplifier and oscillator. On one hand, the large-area pumped slab power amplifier module of this application generates pump light from a pump source, which enters a slab crystal module via a waveguide coupling module. The waveguide coupling module is used to shape and homogenize the pump light and couple it onto the slab crystal module. The slab crystal module absorbs the pump light to generate laser light and simultaneously amplifies the injected seed laser. The slab crystal uses slab crystals with different side sizes; the largest side serves as the pump surface, and the second largest side serves as the laser transmission surface. This differs from the traditional principle where the seed laser enters from one end of the slab crystal along its length. The solution involves coating the pump surface with a pump light antireflection film and a laser high reflectivity film, and coating the laser light transmission surface with a seed light antireflection film and a laser antireflection film. This makes it possible to set the pump surface and the laser light transmission surface opposite each other, which can effectively reduce the laser thermal effect, improve the utilization rate of the gain medium, make full use of the gain medium to reverse the ion number and improve the energy extraction efficiency. It also increases the effective light transmission aperture of the laser and achieves a high peak power density. By using a slab crystal to amplify the low-power, high-beam-quality seed laser, a laser with high output power, high beam quality and narrow pulse width can be obtained, which can meet the application requirements in the field of laser shock peening.

[0018] On the other hand, the large-area pumped slab laser amplifier of this application uses a seed source to generate a seed laser and inject it into a first shaping system. The first and second shaping systems are used to shape the seed laser to achieve matching between the seed laser and the spot size and mode of the amplification stage. A total reflection mirror is used to reflect the laser so that it enters the slab crystal module. The structural design is simple and flexible and can be adjusted to a multi-stage, multi-path slab laser amplifier for application according to actual conditions. The seed laser enters from the second largest surface of the large-area pumped slab power amplifier module. Its main functions are to achieve efficient thermal management in the thickness direction and improve the average power; another is to increase the light transmission aperture and achieve high peak power.

[0019] On the other hand, in the laser oscillator of this application, the pump light is emitted from the pump source, shaped and homogenized by the waveguide coupling module, and injected into the slab crystal module through the pump band antireflection film. The first and second lenses can form an optical resonant cavity, so that the output laser is continuous. Furthermore, after adding a modulation device in the laser resonant cavity, it can be adjusted to a Q-switched or mode-locked pulsed laser output. Compared with traditional technology, this technical solution effectively improves the output power and output stability of the laser amplifier. Attached Figure Description

[0020] Figure 1 This is a structural reference diagram of Embodiment 2 of the present utility model;

[0021] Figure 2 This is a structural reference diagram of Embodiment 1 of the present utility model;

[0022] Figure 3This is a schematic diagram of the optical path of light passing through the slab crystal of this invention;

[0023] Figure 4 This is a schematic diagram of the structure of Embodiment 3 of this utility model;

[0024] Figure 5 This is a partial schematic diagram of the water-cooling device of this utility model;

[0025] Figure 6 This is a schematic diagram of the overall structure of the slat power amplifier module of this utility model;

[0026] Figure 7 This is a schematic diagram of the internal structure of the slat power amplifier module of this utility model;

[0027] Figure 8 This is a side view of the slat amplifier module of this utility model.

[0028] Reference numerals: 1. Seed source; 2. First shaping system; 3. Seed laser; 4. Total reflection mirror; 5. Pump source; 6. Waveguide coupling module; 7. Slab crystal module; 71. Slab crystal; 72. Quartz window; 731. Water inlet; 732. Water outlet; 8. Second shaping system; 9. Focusing lens; 10. First lens; 11. Second lens; 12. Waveguide frame; 13. Module base; 14. Water cooling device; 15. First negative lens; 16. First positive lens; 17. Second negative lens; 18. Second positive lens; 19. Third negative lens; 20. Third positive lens; 21. Pump surface; 22. Laser light transmission surface. Detailed Implementation

[0029] To make the technical means, technical features, utility model purpose and technical effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations.

[0030] Example 1:

[0031] This embodiment provides a large-area pumped slab power amplifier module, such as... Figure 1 As shown, the system includes a pump source 5, a waveguide coupling module 6, and a slab crystal module 7. The slab crystal module 7 includes a slab crystal 71, a water-cooling device 14, and a quartz window 72. The largest surface of the slab crystal 71 is the pump surface 21, which is coated with a pump light antireflection film and a laser high-reflection film. The second largest surface of the slab crystal 71 is the laser light-transmitting surface 22, which is coated with a seed light antireflection film and a laser antireflection film. Preferably, [reference needed]. Figure 5The water-cooling device 14 mainly consists of coolant and coolant flow channels, primarily used to cool the slab crystal module 7. The coolant is deionized water. The coolant flow channels are evenly distributed on both sides of the slab crystal 71, and can be either a loop-shaped or serpentine distribution. The coolant flow channels contain capillaries, which are fine microstructures used to ensure the laminar flow characteristics of the water-cooling device 14 and reduce the impact on pump uniformity and laser wavefront. Preferably... Figure 7 Since the water-cooling device 14 has a relatively small structure, it is not shown in the figure. Please refer to [reference needed]. Figure 6-8 The slab power amplifier module is obtained by welding the waveguide coupling module 6 to the slab crystal module 7, and then fixed to the waveguide frame 12 by screws or welding. The waveguide frame 12 is fixed to the module base 13 by screws. The water cooling device 14 is provided with a water inlet 731 and a water outlet 732 to facilitate the circulation of cooling water. Preferably, both the pump source 5 and the slab crystal module 7 are cooled by circulating cooling water. The pump surface 21 and the laser light transmission surface 22 are arranged opposite each other. Preferably, the pump surface 21 and the laser light transmission surface 22 are parallel to each other.

[0032] The slab crystal 71 is a laser crystal with high thermal conductivity. It is a doped Nd crystal (such as Nd:YAG) to facilitate heat dissipation. Its cross-section can be trapezoidal or rectangular. The cross-section refers to the cross-section orthogonal to the largest or second largest surface. When the laser crystal is rectangular, the areas of the largest and second largest surfaces are the same. The length of the slab crystal 71 is greater than its width and greater than its thickness. It has six surfaces. The largest surface usually refers to the surface orthogonal to the thickness direction. The largest surface has the largest area and is used to install the water cooling device 14 and pump from this surface. The largest surface is coated with a pump light antireflection film and a laser high reflectivity film. The second largest surface is the light transmission surface, where the water cooling device 14 is installed, and seed laser antireflection film and laser high reflectivity film are coated.

[0033] The surface orthogonal to the width direction is usually the side surface. To suppress amplified spontaneous emission (ASE) and parasitic oscillations, it has a wedge angle difference of 1-2 degrees and its surface is roughened. The surface orthogonal to the length direction is the end face, also with a wedge angle difference of 1-2 degrees and its surface roughened, similarly to suppress amplified spontaneous emission (ASE) and parasitic oscillations. The quartz window 72 is located outside the sub-major facet of the lath crystal 71. The laser is output through this window. The quartz window 72 is coated with a seed laser antireflection coating and a laser antireflection coating on both sides. The laser is output through the quartz window 72.

[0034] Preferably, the water cooling device 14 is disposed on one side of the largest surface and one side of the second largest surface of the slab crystal 71, the quartz window 72 is located on one side of the second largest surface of the slab crystal 71, and the water cooling device 14 on this side is located between the quartz window 72 and the slab crystal 71. The water cooling device 14 is used to cool the slab crystal 71.

[0035] Preferably, the pump source 5 is a laser diode bar array, which provides a basis for high-power laser output.

[0036] At work, such as Figure 1 and Figure 3 As shown, pump source 5 generates pump light, which enters slab crystal module 7 via waveguide coupling module 6. Waveguide coupling module 6 is used to shape and homogenize the pump light and couple it into slab crystal module 7. Slab crystal module 7 is used to absorb the pump light to generate laser light and simultaneously amplify the injected seed laser. The slab crystal 71 used has different side sizes, with the largest side serving as pump surface 21 and the second largest side serving as laser light transmission surface 22. Pump surface 21 is coated with pump light antireflection film and laser high reflectivity film, while laser light transmission surface 22 is coated with seed laser light... The antireflection coating and the laser antireflection coating make it possible to set the pump surface 21 and the laser light-passing surface 22 opposite to each other. This can effectively reduce the laser thermal effect, improve the utilization rate of the gain medium, make full use of the gain medium to reverse the ion number and improve the energy extraction efficiency. It also increases the effective light-passing aperture of the laser and achieves a high peak power density. By using the slab crystal 71 to amplify the low-power, high-beam-quality seed laser, a laser with high output power, high beam quality and narrow pulse width can be obtained, which can meet the application requirements in the field of laser shock peening.

[0037] Example 2:

[0038] The similarities between this embodiment and Embodiment 1 will not be repeated here. The difference lies in that this embodiment provides a large-area pumped slab laser amplifier, such as... Figure 2 As shown, the system includes a seed source 1, a first shaping system 2, a total reflection mirror 4, a slab power amplifier module with a pump source 5, a second shaping system 8, and a focusing lens 9. The slab power amplifier module includes a waveguide coupling module 6 and a slab crystal module 7. The seed source 1 is located at the injection end of the first shaping system 2 and is used to generate a seed laser 3 and inject it into the first shaping system 2. The first shaping system 2 is used to shape the seed laser 3 to achieve matching with the size and mode of the amplified spot. The total reflection mirror 4 is used to reflect the laser and inject it into the slab crystal module 7. The pump source 5 is used to generate pump light, which enters the slab crystal module 7 through the waveguide coupling module 6. The waveguide coupling module 6 is used to shape and homogenize the pump light and couple the pump light onto the largest surface of the slab crystal module 7. The slab crystal module 7 is used to absorb the pump light to generate laser light and simultaneously amplify the injected seed laser 3. The second shaping system 8 is used to shape the amplified laser light, and the focusing lens 9 is used to focus the amplified laser light.

[0039] Preferably, the first shaping system 2 includes a first negative lens 15, a first positive lens 16, a second negative lens 17, and a second positive lens 18 arranged sequentially, and the second shaping system 8 includes a third negative lens 19 and a third positive lens 20, thereby expanding and shaping the seed laser 3 to match the amplified spot pattern. The total reflection mirror is coated with a high-reflectivity film for reflecting the laser so that it enters the slab crystal module 7, and the focusing lens is coated with a laser anti-reflection film for focusing the amplified laser.

[0040] Example 3:

[0041] The similarities between this embodiment and Embodiment 1 will not be repeated here. Please refer to... Figure 1 , Figure 3 as well as Figures 5-8 The pump structure therein is the same as the pump structure in Example 1, except that: Figure 4 As shown, this embodiment provides a large-area pumped slab laser oscillator, which utilizes... Figure 2 The schematic diagram of the laser oscillator implemented by the pump structure further includes a first lens 10 and a second lens 11. The first lens 10 is a curved mirror coated with a high-reflectivity film for the oscillating light; the second lens 11 is a plane mirror, with a partial transmittance film for the oscillating light coated on one side facing the laser gain medium and a high-transmittance film coated on the other side, used for outputting intracavity laser. The laser oscillator includes pump light emitted from the pump source 5, shaped and homogenized by the waveguide coupling module 6, passing through the pump band antireflection film, and injected into the slab crystal module 7. The first lens 10 and the second lens 11 form an optical resonant cavity. This slab laser oscillator provides continuous laser output, but can also be adjusted to Q-switched or mode-locked pulsed laser output by adding modulation devices in the laser resonant cavity. Specifically, modulation devices refer to acousto-optic Q-switches, electro-optic Q-switches, semiconductor saturable absorber mirrors (SESAM), etc. Those skilled in the art can choose one or more of these according to the actual situation.

[0042] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. All equivalent changes and modifications made in accordance with the scope of the claims of this utility model should fall within the technical scope of this utility model.

Claims

1. A large-area pumped slab power amplifier module, comprising a pump source (5), a waveguide coupling module (6), and a slab crystal module (7), wherein the slab crystal module (7) comprises a slab crystal (71), a water cooling device (14), and a quartz window (72), characterized in that: The largest surface of the slab crystal (71) is the pump surface (21), which is coated with a pump light antireflection film and a laser high reflectivity film. The second largest surface of the slab crystal (71) is the laser light transmission surface (22), which is coated with a seed light antireflection film and a laser antireflection film. The pump surface (21) and the laser light transmission surface (22) are arranged opposite to each other.

2. The large-area pump slat power amplifier module according to claim 1, characterized in that: The water cooling device (14) is located on one side of the largest surface and the second largest surface of the lath crystal (71). The quartz window (72) is located on one side of the second largest surface of the lath crystal (71), and the water cooling device (14) on that side is located between the quartz window (72) and the lath crystal (71).

3. The large-area pump slat power amplifier module according to claim 1, characterized in that: The cross-section of the lath crystal (71) is trapezoidal or rectangular, and the end face and side face of the lath crystal (71) have a wedge angle difference of 1-2 degrees.

4. The large-area pump slat power amplifier module according to claim 1, characterized in that: The quartz window (72) is coated with a seed laser anti-reflection coating and a laser anti-reflection coating on both sides.

5. The large-area pump slat power amplifier module according to claim 1, characterized in that: The pump source (5) is a laser diode bar array.

6. The large-area pump slat power amplifier module according to claim 1, characterized in that: The water cooling device (14) has an inlet end (731) on one side and an outlet end (732) on the other side. The water flow channel inside the water cooling device (14) contains capillary pores.

7. The large-area pump slat power amplifier module according to claim 1, characterized in that: The waveguide coupling module (6) and the slab crystal module (7) are welded together to form a whole. The slab crystal (71) is a laser crystal with thermal conductivity.

8. A large-area pumped slab laser amplifier, employing the large-area pumped slab power amplifier module of any one of claims 1-7, characterized in that: It also includes a seed source (1), a first shaping system (2), a total reflection mirror (4), a second shaping system (8) and a focusing lens (9). The first shaping system (2) is located between the seed source (1) and the total reflection mirror (4), and the second shaping system (8) is located between the slab crystal module and the focusing lens (9).

9. The large-area pumped slab laser amplifier according to claim 8, characterized in that: The first shaping system (2) includes a first negative lens (15), a first positive lens (16), a second negative lens (17), and a second positive lens (18) arranged in sequence. The second shaping system (8) includes a third negative lens (19) and a third positive lens (20). The total reflection mirror (4) is coated with a laser high-reflection film, and the focusing lens (9) is coated with a laser anti-reflection film.

10. A large-area pumped slab laser oscillator, employing the large-area pumped slab power amplifier module according to any one of claims 1-7, characterized in that: It also includes a first lens (10) and a second lens (11), which are located on both sides of the slab crystal module.

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