Wavelength-adjustable high-power picosecond all-solid-state laser

Abstract

The invention discloses a wavelength-adjustable high-power picosecond all-solid-state laser. The microchip seed source adopts a passive Q-switching principle, can directly generate laser with the pulse width as narrow as 300ps, is high in seed laser efficiency, good in beam quality and large in energy, can synchronously output TTL (transistor-transistor logic) level, and is used for controlling the pulse duration and delay of a 808nm QCW pumping source; the optical isolator protects the front-stage microchip solid laser from being damaged by returned light of the rear-stage amplifier; the single-rod two-way end pump amplifier amplifies laser pulse energy output by the microchip solid laser; the light beam shaper comprises a Galileo laser beam shrinking system and a soft edge diaphragm and is used for shaping light beams; the single-rod one-way end pump amplifier amplifies the pulse energy of the preceding-stage laser; and the frequency multiplier performs frequency conversion on the output laser, and outputs wavelength-adjustable picosecond laser with millifocus magnitude, high power and high beam quality.

Description

Technical Field

[0001] The invention relates to the technical field of ultrashort pulse lasers, and in particular to a high-power picosecond all-solid-state laser with adjustable wavelength. Background Art

[0002] Picosecond pulse lasers have broad application prospects in the fields of material processing, satellite ranging, laser-induced damage, medical diagnosis, scientific research, etc. due to their excellent characteristics of high peak power and narrow pulse width. With the development of laser applications, the requirements for the output energy, beam quality and thermal stability of picosecond pulse lasers are gradually increasing.

[0003] At present, the picosecond lasers used in the field of medical cosmetology for the treatment of pigmentation mainly use the Q-switching method to obtain nanosecond pulses and then use the dye compression technology (SBS) to obtain a laser output of hundreds of picoseconds. The disadvantages of this technical route are that the pulse width is mostly around 900ps, and it is difficult to achieve a narrower pulse width, and the pulse width is unstable; the dye material has a short working life, and the bleached dye needs to be replaced every once in a while, and the maintenance cost is high; and the output wavelength is single, which makes it difficult to meet the requirements of different pathologies for different laser wavelengths. At present, the green lasers used in the field of material processing are mainly obtained by the Q-switching method and then realized by the frequency doubling technology. The disadvantages are that the pulse width is in the nanosecond range, the processing materials are limited, the heat-affected zone is large, and the processing accuracy is low; and it is difficult to achieve high-power laser output through Q-switching technology; the beam quality is poor, and it is difficult to achieve high-precision processing of materials; and the power stability is poor, and it is difficult to operate stably for a long time.

[0004] Therefore, how to achieve narrower pulse width, higher output power, more output wavelengths, higher beam quality and more stable output power has become an important issue that needs to be urgently solved by technicians in this field. Summary of the invention

[0005] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a wavelength-tunable high-power picosecond all-solid-state laser, whose micro-chip seed source can directly generate lasers with a pulse width as narrow as 300ps. The seed laser has high efficiency, good beam quality, and high energy. At the same time, it can synchronously output TTL levels to control the pulse duration and delay of the 808nm QCW pump source.

[0006] The technical solution of the present invention is: the wavelength-adjustable high-power picosecond all-solid-state laser comprises: a microchip seed source (1), an optical isolator (2), a single-rod double-pass end-pump amplifier (3), a beam shaper (4), a single-rod single-pass end-pump amplifier (5) and a frequency multiplier (6);

[0007] The microchip seed source adopts the passive Q-switching principle to output single-mode laser for subsequent amplification; the optical isolator comprises a first thin-film polarizer (8), a first half-wave plate (9), and a 45° Faraday rotator (10) to protect the front-stage microchip solid laser from being damaged by the return light of the rear-stage amplifier; the single-rod double-pass end-pump amplifier amplifies the laser pulse energy output by the microchip solid laser; the beam shaper comprises a Galilean laser beam reduction system and a soft-edge aperture to shape the beam; the single-rod single-pass end-pump amplifier amplifies the pulse energy of the front-stage laser; the frequency multiplier performs frequency conversion on the output laser to output a picosecond laser with adjustable wavelength, millijoule level, high power, and high beam quality.

[0008] The present invention uses a microchip solid-state laser as a seed source, a passive Q-switched crystal with a saturable absorber and a short cavity length, and can directly generate a laser with a pulse width as narrow as 300ps. The seed laser has high efficiency, good beam quality and high energy. At the same time, it can synchronously output TTL levels to control the pulse duration and delay of the 808nm QCW pump source. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic structural diagram of the wavelength-tunable high-power picosecond all-solid-state laser according to the present invention.

[0010] Figure 2 It is a structural schematic diagram of a microchip seed source, an optical isolator and a single-rod double-pass end-pump amplifier of a wavelength-tunable high-power picosecond all-solid-state laser according to the present invention.

[0011] Figure 3 It is a structural schematic diagram of a beam shaper, a single-rod single-pass end-pump amplifier and a frequency doubler of a wavelength-tunable high-power picosecond all-solid-state laser according to the present invention.

[0012] Among them: 1. Microchip seed source; 2. Optical isolator; 3. Single-rod double-pass end-pump amplifier; 4. Beam shaper; 5. Single-rod single-pass end-pump amplifier; 6. Frequency doubler; 7. Microchip solid-state laser; 8. First thin-film polarizer; 9. First half-wave plate; 10. 45° Faraday rotator; 11. First 45° high reflector; 12. Second 45° high reflector; 13. Second thin-film polarizer; 14. Quarter-wave plate; 15. First Nd:YVO4 crystal; 16. First 1064nm high-reflection, 808nm high-transmittance lens; 17. First pump optical coupling module; 18. First 808nm QCW pump source; 19. 0° high reflector Mirror; 20. Plano-convex lens; 21. Plano-concave lens; 22. Soft-edge aperture; 23. The third 45° high reflector; 24. The second Nd:YVO4 crystal; 25. The second 1064nm high reflector and 808nm high transmittance lens; 26. The second pump optical coupling module; 27. The second 808nm QCW pump source; 28. The fourth 45° high reflector; 29. ​​LBO double frequency crystal; 30. LBO triple frequency crystal; 31. Temperature control furnace for double frequency crystal; 32. Temperature control furnace for triple frequency crystal; 33. 355nm high reflector and 1064nm & 532nm high transmittance lens; 34. 532nm high reflector and 1064nm high transmittance lens. DETAILED DESCRIPTION

[0013] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0014] It should be noted that the term "comprises" and any variations in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or equipment.

[0015] like Figure 1 , 2 As shown, this wavelength-tunable high-power picosecond all-solid-state laser comprises: a microchip seed source 1, an optical isolator 2, a single-rod double-pass end-pump amplifier 3, a beam shaper 4, a single-rod single-pass end-pump amplifier 5 and a frequency doubler 6;

[0016] The microchip seed source adopts the passive Q-switching principle to output single-mode laser for subsequent amplification; the optical isolator includes a first thin-film polarizer 8, a first half-wave plate 9, and a 45° Faraday rotator 10 to protect the front-stage microchip solid-state laser from being damaged by the return light of the rear-stage amplifier; the single-rod double-pass end-pump amplifier amplifies the laser pulse energy output by the microchip solid-state laser; the beam shaper includes a Galilean laser beam reduction system and a soft-edge aperture to shape the beam; the single-rod single-pass end-pump amplifier amplifies the pulse energy of the front-stage laser; the frequency doubler performs frequency conversion on the output laser to output a picosecond laser with adjustable wavelength, millijoule level, high power, and high beam quality.

[0017] The present invention uses a microchip solid-state laser as a seed source, a passive Q-switched crystal with a saturable absorber and a short cavity length, and can directly generate a laser with a pulse width as narrow as 300ps. The seed laser has high efficiency, good beam quality and high energy. At the same time, it can synchronously output TTL levels to control the pulse duration and delay of the 808nm QCW pump source.

[0018] Preferably, the microchip seed source is a microchip solid-state laser 7, with an output of 1064 nm in the order of hundreds of picoseconds, an adjustable pulse repetition frequency of 1 kHz-10 kHz, and a beam quality factor M 2 The high beam quality and high energy single-mode laser with a power of less than 1.01 can output TTL level synchronously to control the pulse duration and delay of the 808nm QCW pump source.

[0019] Preferably, the laser is converted into a horizontal polarization state through an optical isolator and then reflected by a first 45° high reflector 11 and a second 45° high reflector 12 into a single-rod double-pass end-pump amplifier for energy amplification.

[0020] Preferably, the single-rod double-pass end-pump amplifier comprises a second thin-film polarizer 13, a quarter-wave plate 14, a first Nd:YVO4 crystal 15, a first 1064nm high-reflection, 808nm high-transmittance lens 16, a first pump light coupling module 17, a first 808nm QCW pump source 18 and a 0° high-reflection mirror 19; the horizontally polarized laser to be amplified passes through the second thin-film polarizer 13 and then passes through the quarter-wave plate 14 for the first time to become right-handed circularly polarized light, then passes through the first Nd:YVO4 crystal 15, the first 1064nm high-reflection, 808nm high-transmittance lens 16 in sequence, and is finally reflected by the 0° high-reflection mirror. The laser returns along the original optical path, passes through the first 1064nm high-reflection, 808nm high-transmittance lens, the first Nd:YVO4 crystal in sequence, passes through the quarter-wave plate for the second time to become a vertically polarized laser, is reflected by the second thin-film polarizer, and is injected into the beam shaper.

[0021] Preferably, the size of the first Nd:YVO4 crystal is 3mm×3mm×10mm, the doping concentration is 0.3at%, and both end faces are plated with 1064nm&808nm anti-reflection films. A 0.5° wedge angle is processed at one end of the crystal to prevent the crystal from self-excited oscillation. The crystal is wrapped with indium foil and placed in a copper heat sink, and is water-cooled to ensure its safe operation. The 808nm QCW pump source adopts a quasi-continuous pumping mode, outputs 808nm, 1kHz repetition frequency, and 100μs pulse duration laser, and controls the repetition frequency, pulse duration and pump light delay of the output laser by an external TTL level. The beam shaper includes a plano-convex lens 20, a plano-concave lens 21 and a soft-edge aperture 22. The plano-convex lens and the plano-concave lens form a Galilean laser beam reduction system to control the size of the laser spot. The soft-edge aperture performs beam shaping on the Gaussian beam output by the single-rod double-pass end-pump amplifier to achieve uniform laser output.

[0022] Preferably, the soft-edge aperture has a binary amplitude distribution.

[0023] Preferably, the laser light homogenized by the soft-edge aperture is reflected by the third 45° high-reflection mirror 23 and enters the single-rod single-pass end-pump amplifier.

[0024] Preferably, the single-rod single-pass end-pump amplifier comprises a second Nd:YVO4 crystal 24, a second 1064nm high-reflection, 808nm high-transmittance lens 25, a second pump light coupling module 26, and a second 808nmQCW pump source 27; the second Nd:YVO4 crystal and the second 808nmQCW pump source have the same parameters as the first Nd:YVO4 crystal and the first 808nmQCW pump source, and the second pump light coupling module shapes the pump light output by the second 808nmQCW pump source, and matches the laser to be amplified output by the beam shaper inside the second Nd:YVO4 crystal.

[0025] Preferably, after the single-rod single-pass end-pump amplifier further amplifies the laser pulse energy, the emitted laser is reflected by the fourth 45° high-reflection mirror 28 and enters the frequency doubler.

[0026] Preferably, the frequency doubler comprises an LBO double frequency crystal 29, an LBO triple frequency crystal 30, a double frequency crystal temperature control furnace 31, a triple frequency crystal temperature control furnace 32, a 355nm high reflection, 1064nm & 532nm high transmission lens 33, and a 532nm high reflection, 1064nm high transmission lens 34; the LBO double frequency crystal adopts a type I phase matching condition, and the 1064nm laser amplified by a single-rod single-pass end-pump amplifier passes through the LBO double frequency crystal and then doubles the frequency to generate 5 The 32nm laser and the 1064nm laser enter the LBO tripled frequency crystal together to generate a 355nm laser. The three wavelengths of light are emitted together. When passing through the 355nm high-reflection, 1064nm & 532nm high-transmittance lens, the 355nm laser is reflected, and the 1064nm and 532nm lights pass through the lens. Then, after passing through the 532nm high-reflection, 1064nm high-transmittance lens, the 532nm light is reflected, and the 1064nm light passes through the lens.

[0027] The present invention is described in more detail below.

[0028] Figure 1 A structural block diagram of a wavelength-tunable high-power picosecond all-solid-state laser provided by an embodiment of the present invention, such as Figure 1 As shown, it includes a microchip seed source 1, an optical isolator 2, a single-rod double-pass end-pump amplifier 3, a beam shaper 4, a single-rod single-pass end-pump amplifier 5 and a frequency doubler 6. The microchip seed source is composed of a microchip solid-state laser 7, which is used to generate a 1064nm hundred-picosecond pulse laser with adjustable repetition rate, high beam quality and high stability; the optical isolator 2 is used to protect the front-stage laser from being damaged by the reflected light of the back-stage amplifier; the single-rod double-pass end-pump amplifier 3 is used to amplify the laser pulse energy output by the microchip solid-state laser with high quality; the beam shaper 4 is used to achieve high-efficiency beam shaping and achieve uniform output of the laser; the single-rod single-pass end-pump amplifier 5 further amplifies the energy of the front-stage laser pulse; finally, the frequency doubler 6 performs frequency conversion on the output laser, and finally achieves the output of picosecond laser with adjustable wavelength, high power and high beam quality in the millijoule level.

[0029] Figure 2A schematic diagram of the structure of a microchip seed source 1, an optical isolator 2 and a single-rod double-pass end-pump amplifier 3 of a wavelength-adjustable high-power picosecond all-solid-state laser provided in an embodiment of the present invention; wherein the microchip seed source 1 is composed of a microchip solid-state laser 7, and is used to generate 1064nm 100-picosecond laser pulses with high beam quality and high stability with adjustable repetition rate; the optical isolator 2 is composed of a first thin-film polarizer 8, a first half-wave plate 9 and a 45° Faraday rotator 10, and is used to protect the front-stage laser from being damaged by reflected light from the rear-stage amplifier; After the laser is converted into a horizontal polarization state through the optical isolator 2, it is reflected by the first 45° high reflector 11 and the second 45° high reflector 12 into the single-rod double-pass end-pump amplifier 3 for energy amplification; wherein the single-rod double-pass end-pump amplifier 3 is composed of a second thin-film polarizer 13, a quarter-wave plate 14, a first Nd:YVO4 crystal 15, a first 1064nm high-reflection, 808nm high-transmittance lens 16, a first pump light coupling module 17, a first 808nm QCW pump source 18 and a 0° high reflector 19. The horizontal polarization laser to be amplified passes through the second thin-film polarizer 13 and then passes through the quarter-wave plate 14 for the first time to become right-handed circularly polarized light, then passes through the first Nd:YVO4 crystal 15, the first 1064nm high-reflection, 808nm high-transmittance lens 16 in sequence, and is finally reflected by the 0° high-reflection mirror 19. The laser returns along the original optical path, passes through the first 1064nm high-reflection, 808nm high-transmittance lens 16 and the first Nd:YVO4 crystal 15 in sequence, and then passes through the quarter-wave plate 14 for the second time to become vertically polarized laser, which is reflected by the second thin-film polarizer 13 and injected into the beam shaper 4. The first pump light coupling module 17 is used to shape the quasi-continuous laser with 808nm, 1kHz repetition frequency, and 100μs pulse duration output by the first 808nmQCW pump source 18, controls the matching of the pump light and the seed light inside the first Nd:YVO4 crystal 15, and improves the amplification efficiency.

[0030] Figure 3A schematic diagram of the structure of a beam shaper 4, a single-rod single-pass end-pump amplifier 5 and a frequency doubler 6 of a wavelength-adjustable high-power picosecond all-solid-state laser provided in an embodiment of the present invention; the beam shaper 4 is composed of a plano-convex lens 20, a plano-concave lens 21 and a soft-edge aperture 22. The plano-convex lens 20 and the plano-concave lens 21 form a Galilean laser beam reduction system to control the size of the laser spot. The soft-edge aperture 22 is used to shape the Gaussian beam output by the single-rod double-pass end-pump amplifier 3 to achieve uniform output of the laser. The homogenized laser is reflected by the third 45° high-reflection mirror 23 and enters the single-rod single-pass end-pump amplifier 5. The single-rod single-pass end-pump amplifier 5 is composed of a second Nd:YVO4 crystal 24, a second 1064nm high-reflection, 808nm high-transmittance lens 25, a second pump light coupling module 26, and a second 808nm QCW pump source 27. The second Nd:YVO4 crystal 24 and the second 808nmQCW pump source 27 have the same parameters as the first Nd:YVO4 crystal 15 and the first 808nmQCW pump source 18. The second pump light coupling module 26 shapes the pump light output by the second 808nmQCW pump source, and matches the laser to be amplified output by the beam shaper 4 inside the second Nd:YVO4 crystal 24 to improve the amplification efficiency. After the single-rod single-pass end pump amplifier 5 further amplifies the laser pulse energy, the emitted laser is reflected by the fourth 45° high reflector 28 and enters the frequency doubler 6. The frequency doubler 6 is composed of an LBO double frequency crystal 29, an LBO triple frequency crystal 30, a double frequency crystal temperature control furnace 31, a triple frequency crystal temperature control furnace 32, a 355nm high reflection, 1064nm & 532nm high transmission lens 33, and a 532nm high reflection, 1064nm high transmission lens 34. The LBO double frequency crystal 29 adopts the Class I phase matching condition. The 1064nm laser amplified by the single-rod single-pass end pump amplifier 5 passes through the LBO double frequency crystal 29 and then doubles to produce a 532nm laser. It enters the LBO triple frequency crystal 30 together with the 1064nm laser to produce a 355nm laser. The three wavelengths of light are emitted together. When passing through the 355nm high reflection, 1064nm & 532nm high transmission lens 33, the 355nm laser is reflected, and the 1064nm and 532nm lights pass through the lens. Then, after passing through the 532nm high reflection, 1064nm high transmission lens 34, the 532nm light is reflected, and the 1064nm light passes through the lens, thereby realizing the free selection of the output wavelength. Among them, the double frequency crystal temperature control furnace 31 and the triple frequency crystal temperature control furnace 32 can realize the high-precision temperature control of the LBO double frequency crystal and ensure the frequency doubling efficiency.

[0031] The beneficial technical effects of the present invention are as follows:

[0032] 1. Using microchip solid-state laser as seed source, passive Q-switched crystal with saturable absorber and short cavity length, it can directly generate laser with pulse width as narrow as 300ps, with high seed laser efficiency, good beam quality and high energy. At the same time, it can synchronously output TTL level to control the pulse duration and delay of 808nm QCW pump source.

[0033] 2. The energy of the pulsed laser is amplified by end-pumping Nd:YVO4 crystal. At the same time, a 0.5° wedge angle is processed on one end of the Nd:YVO4 crystal to prevent self-oscillation of the crystal, which can achieve high-quality amplification of the laser pulse energy.

[0034] 3. The laser crystal is pumped by quasi-continuous pumping, which has less thermal effect and higher amplification efficiency. The 808nm QCW pump source outputs 808nm, 1kHz repetition frequency, 100μs pulse duration laser, and the repetition frequency, pulse duration and pump light delay of the output laser can be controlled by external TTL level.

[0035] 4. Introducing a beam shaper to shape the seed laser spot, and using a pump light coupling module to shape the pump spot, can achieve a good match between the pump light and the seed light, improving the amplification efficiency. The soft-edge aperture homogenizes the Gaussian laser beam to avoid strong spots in the laser during amplification and improve the beam quality of the laser after amplification.

[0036] 5. The energy of the pulse laser is amplified by single-rod double-pass end pumping and single-rod single-pass end pumping respectively. This step-by-step amplification method can effectively amplify the energy of the pulse laser while ensuring high beam quality.

[0037] 6. Using LBO crystal as the frequency doubling crystal has high damage threshold, large nonlinear coefficient, good environmental stability and wide phase matching range. The double frequency uses type I phase matching, and the triple frequency uses type II phase matching, with high frequency doubling conversion efficiency.

[0038] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A wavelength-tunable high-power picosecond all-solid-state laser, characterized in that: It includes: A microchip seed source (1), an optical isolator (2), a single-rod double-pass end-pump amplifier (3), a beam shaper (4), a single-rod single-pass end-pump amplifier (5) and a frequency doubler (6); The microchip seed source adopts the passive Q-switching principle to output single-mode laser for subsequent amplification; the optical isolator comprises a first thin-film polarizer (8), a first half-wave plate (9), and a 45° Faraday rotator (10) to protect the front-stage microchip solid laser from being damaged by the return light of the rear-stage amplifier; the single-rod double-pass end-pump amplifier amplifies the laser pulse energy output by the microchip solid laser; the beam shaper comprises a Galilean laser beam reduction system and a soft-edge aperture to shape the beam; the single-rod single-pass end-pump amplifier amplifies the pulse energy of the front-stage laser; the frequency multiplier performs frequency conversion on the output laser to output a picosecond laser with adjustable wavelength, millijoule level, high power, and high beam quality.

2. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 1, characterized in that: The microchip seed source is a microchip solid laser (7) with an output of 1064nm at the level of hundreds of picoseconds, an adjustable pulse repetition frequency of 1kHz-10kHz, and a beam quality factor M 2 The single-mode laser with high beam quality and high energy is less than 1.01, and the TTL level is output synchronously to control the pulse duration and delay of the 808nm QCW pump source.

3. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 2, characterized in that: After the laser is converted into a horizontal polarization state through an optical isolator, it is reflected by a first 45° high reflector (11) and a second 45° high reflector (12) and enters a single-rod double-pass end-pump amplifier for energy amplification.

4. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 3, characterized in that: The single-rod double-pass end-pump amplifier comprises a second thin-film polarizer (13), a quarter-wave plate (14), a first Nd:YVO4 crystal (15), a first 1064nm high-reflection, 808nm high-transmittance lens (16), a first pump light coupling module (17), a first 808nm QCW pump source (18) and a 0° high-reflection mirror (19); after the horizontal polarization state laser to be amplified passes through the second thin-film polarizer (13), it passes through the quarter-wave plate (14) for the first time to become right-handed circularly polarized light, then passes through the first Nd:YVO4 crystal (15), the first 1064nm high-reflection, 808nm high-transmittance lens (16) in sequence, and is finally reflected by the 0° high-reflection mirror. The laser returns along the original optical path, passes through the first 1064nm high-reflection, 808nm high-transmittance lens, the first Nd:YVO4 crystal in sequence, passes through the quarter-wave plate for the second time to become vertically polarized state laser, is reflected by the second thin-film polarizer, and is injected into the beam shaper.

5. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 4, characterized in that: The first Nd:YVO4 crystal has a size of 3mm×3mm×10mm and a doping concentration of 0.3at%. Both end faces are plated with 1064nm&808nm anti-reflection films. A 0.5° wedge angle is processed at one end of the crystal to prevent the crystal from self-excited oscillation. The crystal is wrapped with indium foil and placed in a copper heat sink, and is cooled with water to ensure its safe operation. The 808nm QCW pump source adopts a quasi-continuous pumping mode to output a laser with a wavelength of 808nm, a repetition frequency of 1kHz, and a pulse duration of 100μs. The repetition frequency, pulse duration, and pump light delay of the output laser are controlled by an external TTL level. The beam shaper comprises a plano-convex lens (20), a plano-concave lens (21), and a soft-edge aperture (22). The plano-convex lens and the plano-concave lens form a Galilean laser beam reduction system to control the size of the laser spot. The soft-edge aperture shapes the Gaussian beam output by the single-rod double-pass end-pump amplifier to achieve uniform laser output.

6. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 5, characterized in that: The soft-edge aperture has a binary amplitude distribution.

7. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 6, characterized in that: The laser light homogenized by the soft-edge aperture is reflected by the third 45° high-reflection mirror (23) and enters the single-rod single-pass end-pump amplifier.

8. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 7, characterized in that: The single-rod single-pass end-pump amplifier comprises a second Nd:YVO4 crystal (24), a second 1064nm high-reflection and 808nm high-transmittance lens (25), a second pump light coupling module (26), and a second 808nm QCW pump source (27); the second Nd:YVO4 crystal and the second 808nm QCW pump source have the same parameters as the first Nd:YVO4 crystal and the first 808nm QCW pump source; the second pump light coupling module shapes the pump light output by the second 808nm QCW pump source, and matches the laser light to be amplified output by the beam shaper inside the second Nd:YVO4 crystal.

9. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 8, characterized in that: After the single-rod single-pass end-pump amplifier further amplifies the laser pulse energy, the emitted laser is reflected by the fourth 45° high-reflection mirror (28) and enters the frequency doubler.

10. The wavelength-tunable high-power picosecond all-solid-state laser according to claim 9, characterized in that: The frequency multiplier comprises an LBO double frequency crystal (29), an LBO triple frequency crystal (30), a double frequency crystal temperature control furnace (31), a triple frequency crystal temperature control furnace (32), a 355nm high reflection, 1064nm & 532nm high transmission lens (33), and a 532nm high reflection, 1064nm high transmission lens (34); the LBO double frequency crystal adopts a type I phase matching condition, and the 1064nm laser amplified by a single-rod single-pass end pump amplifier passes through the LBO double frequency crystal and then doubles to generate a 532nm laser, which enters the LBO triple frequency crystal together with the 1064nm laser to generate a 355nm laser, and the three wavelengths of light are emitted together, and after passing through the 355nm high reflection, When using the 1064nm&532nm high-transmittance lens, the 355nm laser is reflected, the 1064nm and 532nm light passes through the lens, and then passes through the 532nm high-reflection and 1064nm high-transmittance lens, the 532nm light is reflected, and the 1064nm light passes through the lens.

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