A wavelength-tunable multi-medium high-efficiency laser amplification device and method

Abstract

The application provides a wavelength-adjustable multi-medium high-efficiency laser amplification device and method, which comprises a pump source, a first laser amplification system and a second laser amplification system arranged in sequence. The first laser amplification system comprises a first pump mirror, a first gain medium and a first partial mirror arranged in sequence. Pump light emitted by the pump source transmits into the first gain medium through the first pump mirror, is amplified by the first gain medium and then transmits to the first partial mirror. The second laser amplification system comprises a second pump mirror, a second gain medium and a second partial mirror arranged in sequence. The first gain laser beam transmits into the second gain medium through the second pump mirror, is amplified by the second gain medium and then transmits to the second partial mirror. The first gain medium is wrapped by a SiO2 crystal, an Au film and a plastic shell in sequence from outside. The SiO2 crystal and the Au film are interlaid with nanowires. The laser wavelength can be tuned by selecting a suitable film thickness ratio K of the SiO2 crystal and the Au film.

Description

Technical Field

[0001] This invention belongs to the field of laser amplification technology, and specifically relates to a wavelength-tunable multi-medium high-efficiency laser amplification device and method. Background Technology

[0002] High-energy lasers, characterized by their high energy and specific wavelengths, have wide applications in precision industrial machining, medical treatment, and military defense. Currently, the most advanced laser amplification technology utilizes cooled end-face pumped slab lasers for amplification, effectively increasing the absorption of pump light by the gain medium and achieving high-power, high-beam-quality laser output. Combining this with master oscillator power amplification technology can further increase the laser's output power, obtaining high-power fundamental frequency light. While this method can achieve high-power laser output, it suffers from the fatal drawback of untunable output laser beam wavelength, limiting the output to a fixed wavelength and making it difficult to precisely match the corresponding solid-state gain medium, thus restricting the application areas of high-power lasers. Therefore, researching multi-stage laser amplification methods with tunable high-power laser wavelengths is of great significance. Summary of the Invention

[0003] To address the problems of untunable output laser beam wavelength, difficulty in matching solid-state gain media, and single gain media in existing lasers, this invention provides a wavelength-tunable multi-medium high-efficiency laser amplification device and method. The Burstein-Moss effect can be controlled by selecting an appropriate SiO2 crystal to Au thin film thickness ratio K, thereby tuning the laser wavelength.

[0004] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0005] A wavelength-tunable multi-medium high-efficiency laser amplification device is characterized by comprising a pump source, a primary laser amplification system, and a secondary laser amplification system arranged sequentially.

[0006] The first-stage laser amplification system includes a first pump mirror, a first gain medium, and a first partial reflector arranged sequentially. The left and right ends of the first pump mirror are respectively positioned facing the pump source and the inlet of the first gain medium on the first gain medium. The first partial reflector is positioned facing the outlet of the first gain medium on the first gain medium, so that the pump light emitted from the pump source passes through the first pump mirror and enters the first gain medium, is amplified by the first gain medium, and is transmitted to the first partial reflector.

[0007] The first gain medium is wrapped with SiO2 crystal, Au film and plastic shell in sequence, with nanowires sandwiched between SiO2 crystal and Au film.

[0008] The two-stage laser amplification system includes a second pump mirror, a second gain medium, and a second partial reflector arranged sequentially. The left and right ends of the second pump mirror are respectively positioned facing the inlet of the second gain medium on the first partial reflector and the second gain medium. The second partial reflector is positioned facing the outlet of the second gain medium on the second gain medium. This allows the first gain laser beam amplified by the first-stage laser amplification system to pass through the second pump mirror into the second gain medium, be amplified by the second gain medium, and then transmitted to the second partial reflector.

[0009] Furthermore, a first collimating mirror is disposed between the first partial reflector and the second pump mirror to collimate the first gain laser beam transmitted from the first partial reflector into parallel light.

[0010] Furthermore, a second collimating mirror and a focusing mirror are sequentially installed on the right end of the second part of the reflector, so that the second gain laser beam transmitted from the second part of the reflector is collimated into parallel light by the second collimating mirror and then focused by the focusing mirror.

[0011] Furthermore, the second gain medium is coated with a high-reflectivity film on its outer side.

[0012] Furthermore, the first gain medium is disposed in a first cooling tank containing coolant; the second gain medium is disposed in a second cooling tank containing coolant; and each pair of opposite corners of the first and second cooling tanks is provided with an inlet and an outlet for coolant to enter and exit.

[0013] Furthermore, the first gain medium is configured in the form of a coil.

[0014] Furthermore, the first gain medium material is one of germanium-doped quartz, ZBLAN optical fiber, and sulfide.

[0015] Furthermore, the nanowires are made of tungsten diselenide; the plastic shell can be used as a thermally conductive material.

[0016] Furthermore, the second gain medium material is one of ND:LuAG ceramic, ND:CaF crystal, ND:YAG crystal, Yb:S-FAP crystal, and Yb:YAG.

[0017] Furthermore, the coolant is one of the following: glycerin-based coolant, ethylene glycol-based coolant, or water.

[0018] Furthermore, the first gain medium inlet end face forms an acute or obtuse angle with the horizontal plane; the second gain medium inlet end face forms an acute or obtuse angle with the horizontal plane.

[0019] Furthermore, a certain distance is set between the first collimating mirror and the first partial reflector; and the longitudinal cross-sectional area of ​​the second gain medium is greater than that of the first gain medium.

[0020] Furthermore, the first gain medium has a circular longitudinal cross-sectional shape; the second gain medium has a longitudinal cross-sectional shape that is one of a circle, a square, or a rectangle.

[0021] A wavelength-tunable multi-medium high-efficiency laser amplification method, employing the aforementioned wavelength-tunable multi-medium high-efficiency laser amplification device, comprises the following specific steps:

[0022] S1. Based on the required wavelength of the first gain laser beam, determine the film thickness ratio K of SiO2 crystal and Au thin film, and make SiO2 crystal, Au thin film and plastic shell sequentially stacked to wrap the first gain medium, and nanowires are interspersed between SiO2 crystal and Au thin film.

[0023] S2. Place the wrapped first gain medium into the first cooling box;

[0024] S3. Select the appropriate second gain medium according to the wavelength of the first gain laser beam, and wrap a high-reflectivity film on the outside of the second gain medium;

[0025] S4. Place the wrapped second gain medium into the second cooling box;

[0026] S5. Add coolant to the inlets of the first and second cooling tanks so that the first and second cooling tanks are filled with flowing coolant;

[0027] S6. Control the pump source to emit pump light, so that the pump light is amplified by the first-stage laser amplification system and the second-stage laser amplification system in sequence, and then directed towards the target object from the focusing lens;

[0028] S7. After completion, turn off all devices and disconnect the power.

[0029] The beneficial effects of this invention are:

[0030] The laser amplification device of this invention can tune the laser wavelength by controlling the Burstein-Moss effect through the appropriate film thickness ratio K of SiO2 crystal and Au thin film. Nanowires are used to enhance the Burstein-Moss effect, thereby enabling better tuning of the laser wavelength. Specifically, the interfilm plasmons of the SiO2 crystal and Au thin film reinforced by nanowires interact with the excitons of the first gain medium itself, ultimately changing the band distribution of the first gain medium and affecting the peak position of its emission spectrum, i.e., the center wavelength of the laser output. Simultaneously, based on the adjusted and tuned wavelength, a suitable second gain medium is selected, allowing for better amplification of the first-gain laser beam after amplification by the first-stage laser amplification system.

[0031] In this invention, the inlet faces of the first and second gain media form acute or obtuse angles with the horizontal plane. Combined with the reflection of light by the Au thin film and high-reflectivity film, light can propagate in a zigzag pattern within the first and second gain media, significantly increasing the propagation distance and improving the amplification effect. The first part of the reflector, in conjunction with the first pump mirror, and the second part of the reflector, in conjunction with the second pump mirror, allows light to be amplified multiple times within the first and second gain media, greatly enhancing the amplification effect and achieving highly efficient light amplification. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the wavelength-tunable multi-media high-efficiency laser amplification device of the present invention.

[0033] Figure 2 This is a longitudinal cross-sectional view of the first gain medium of the present invention.

[0034] Figure 3 This is a schematic diagram showing the distribution of the nanowires described in this invention.

[0035] Figure 4 This is a schematic diagram of the propagation of the pump light in the first gain medium according to the present invention.

[0036] In the figure, 1. Pump source, 2. Pump light, 3. First gain medium inlet, 4. First gain medium, 5. Coolant, 6. First cooling box inlet, 7. First collimating lens, 8. Second pump lens, 9. Second gain medium inlet, 10. High-reflection coating, 12. Second cooling box inlet, 13. Second collimating lens, 14. Focusing lens, 15. First pump lens, 16. First cooling box outlet, 17. First cooling box, 18. First gain medium outlet, 19. First partial reflector, 20. First gain laser beam, 21. Second cooling box outlet, 22. Second gain medium, 23. Second cooling box, 24. Second partial reflector, 25. Second gain laser beam, 26. Second gain medium outlet, 41. SiO2 crystal, 42. Nanowire, 43. Au thin film, 44. Plastic shell. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0038] The wavelength-tunable multi-medium high-efficiency laser amplification device described in this invention, such as... Figure 1 As shown, it includes a pump source 1, a first-stage laser amplification system and a second-stage laser amplification system arranged in sequence. The pump light 2 emitted by the pump source 1 is amplified by the first-stage laser amplification system and the second-stage laser amplification system in sequence to obtain a high-power, high-beam-quality laser output.

[0039] The first-stage laser amplification system includes a first pump mirror 15, a first gain medium 4, and a first partial reflector 19 arranged sequentially. The left and right ends of the first pump mirror 15 are respectively positioned facing the pump source 1 and the first gain medium inlet 3 on the first gain medium 4. The first partial reflector 19 is positioned facing the first gain medium outlet 18 on the first gain medium 4, allowing the pump light 2 emitted from the pump source 1 to pass through the first pump mirror 15 into the first gain medium 4, be amplified by the first gain medium 4, and then transmitted to the first partial reflector 19. The first gain medium 4 is made of one of the following materials: germanium-doped quartz, ZBLAN fiber, or sulfide, and can amplify the pump light 2 emitted from the pump source 1. The first pump mirror 15 can fully transmit the pump light 2 emitted from the pump source 1, and exhibits total internal reflection of light incident in the opposite direction towards the first pump mirror 15. The first reflector 19 partially reflects the pump light 2, which has been amplified by the first gain medium 4, back into the first gain medium 4. After being amplified again by the first gain medium 4, the pump light 2 is directed toward the first pump mirror 15. The first pump mirror 15 performs total internal reflection of the light incident from the opposite direction. Thus, the pump light 2 can be amplified multiple times in the first gain medium 4 until it is amplified to the amplification threshold of the first gain medium 4.

[0040] like Figure 2-3 As shown, the first gain medium 4 has a circular longitudinal cross-section. SiO2 crystal 41, Au thin film 43, and plastic shell 44 are sequentially stacked and wrapped around the first gain medium 4. Nanowires 42 are sandwiched between the SiO2 crystal 41 and Au thin film 43. The Burstein-Moss effect can be tuned by selecting an appropriate SiO2 crystal to Au thin film thickness ratio K, thereby tuning the laser wavelength. The nanowires 42 are used to enhance the Burstein-Moss effect, thus enabling better tuning of the laser wavelength. Specifically, the interfilm plasmons of the SiO2 crystal and Au thin film reinforced by the nanowires 42 couple with the excitons of the first gain medium 4 itself, ultimately changing the band distribution of the first gain medium 4 and affecting its emission spectrum peak position, i.e., the center wavelength of the laser output. The nanowires 42 are made of tungsten diselenide. Figure 4As shown, the end face of the first gain medium inlet 3 forms an acute or obtuse angle with the horizontal plane, meaning the end face of the first gain medium inlet 3 is inclined relative to the horizontal plane. This causes the horizontal pump light 2 to refract upon entering the first gain medium 4, and the Au thin film 43 reflects the pump light 2, resulting in a zigzag propagation of the pump light 2 within the first gain medium 4. This significantly increases the propagation distance of the pump light 2 within the first gain medium 4, improving the amplification effect of the first gain medium 4 on the pump light 2. The first gain medium 4 is also coil-shaped, further increasing the propagation distance of the pump light 2 within the first gain medium 4, enabling the pump light 2 to achieve a better amplification effect. The first gain medium 4 is disposed within a first cooling tank 17 containing coolant 5. The first cooling tank 17 has a first cooling tank inlet 6 at its upper right corner and a first cooling tank outlet 16 at its lower left corner, ensuring the coolant 5 flows throughout the first cooling tank 17 and enhancing the cooling effect. The coolant 5 is one of glycerol-based, ethylene glycol-based, or water-based coolants, used to cool the first gain medium 4 and prevent thermal interference with its material properties and wavelength stability. The plastic outer shell 44 is a thermally conductive material used to isolate the Au film 43 from the coolant 5, and also facilitates heat exchange between the coolant 5 and the first gain medium 4, SiO2 crystal 41, and Au film 43.

[0041] The two-stage laser amplification system includes a second pump mirror 8, a second gain medium 22, and a second partial reflector 24 arranged sequentially. The left and right ends of the second pump mirror 8 are respectively positioned facing the first partial reflector 19 and the second gain medium inlet 9 on the second gain medium 22. The second partial reflector 24 is positioned facing the second gain medium outlet 26 on the second gain medium 22. This allows the first gain laser beam 20, amplified by the first-stage laser amplification system, to pass through the second pump mirror 8 into the second gain medium 22, be amplified by the second gain medium 22, and then transmitted to the second partial reflector 24. A first collimating mirror 7 is positioned between the first partial reflector 19 and the second pump mirror 8 to collimate the first gain laser beam 20 transmitted from the first partial reflector 19 into parallel light. A certain distance is set between the first collimating mirror 7 and the first partial reflector 19 to expand the first gain laser beam 20 after it has been amplified by the first-stage laser amplification system. This prevents the energy of the first gain laser beam 20 from being too concentrated and damaging the second gain medium 22. Furthermore, the longitudinal cross-sectional area of ​​the second gain medium 22 is larger than that of the first gain medium 4, so that the expanded first gain laser beam 20 can completely enter the second gain medium 22.

[0042] The second gain medium 22 is made of one of the following materials: ND:LuAG ceramic, ND:CaF2 crystal, ND:YAG crystal, Yb:S-FAP crystal, or Yb:YAG. It is used to further amplify the first gain laser beam 20 after it has been amplified by the first-stage laser amplification system. The material of the second gain medium 22 can be selected according to the wavelength of the first gain laser beam 20. The second gain medium 22 is placed in a second cooling tank 23 containing coolant 5. The second cooling tank 23 has a second cooling tank inlet 12 in the upper right corner and a second cooling tank outlet 21 in the lower left corner, so that the coolant 5 in the entire second cooling tank 23 is in a flowing state, which enhances the cooling effect. The coolant 5 is one of glycerol-based coolant, ethylene glycol-based coolant, or water, and is used to cool the second gain medium 22 to avoid thermal effects on the material properties and unstable changes in the wavelength of the second gain medium 22. The second gain medium 22 has a longitudinal cross-sectional shape of one of a circle, a square, or a rectangle. A high-reflectivity film 10 is wrapped around the outside of the second gain medium 22, serving two purposes: firstly, to isolate the second gain medium 22 from the coolant 5 inside the second cooling tank 23, and secondly, to reflect light. The end face of the second gain medium inlet 9 forms an acute or obtuse angle with the horizontal plane, meaning the end face of the second gain medium inlet 9 is inclined relative to the horizontal plane. This allows the first gain laser beam 20, collimated by the first collimating lens 7, to enter the second gain medium inlet 9 horizontally. The first gain laser beam 20 is refracted, and combined with the reflection of the first gain laser beam 20 by the high-reflectivity film 10, the first gain laser beam 20 propagates in a zigzag pattern within the second gain medium 22, greatly increasing the propagation distance of the first gain laser beam 20 within the second gain medium 22 and improving the amplification effect of the second gain medium 22 on the first gain laser beam 20. The second collimating mirror 13 and the focusing mirror 14 are sequentially arranged at the right end of the second part of the reflector 24. The second gain laser beam 25 transmitted from the second part of the reflector 24 is collimated into parallel light by the second collimating mirror 13 and then focused by the focusing mirror 14, and then directed towards the target object from the focusing mirror 14.

[0043] A wavelength-tunable, multi-medium, high-efficiency laser amplification method includes the following steps:

[0044] S1. Based on the required wavelength of the first gain laser beam 20, determine the film thickness ratio K of SiO2 crystal 41 and Au thin film 43, and make SiO2 crystal 41, Au thin film 43 and plastic shell 44 sequentially stacked to wrap the first gain medium 4, and nanowires 42 are sandwiched between SiO2 crystal 41 and Au thin film 43.

[0045] S2. Place the wrapped first gain medium 4 into the first cooling box 17;

[0046] S3. Select the appropriate second gain medium 22 according to the wavelength of the first gain laser beam 20, and wrap a high reflectivity film 10 on the outside of the second gain medium 22;

[0047] S4. Place the wrapped second gain medium 22 into the second cooling box 23;

[0048] S5. Add coolant 5 to the inlets of the first cooling tank 17 and the second cooling tank 23 so that the first cooling tank 17 and the second cooling tank 23 are filled with flowing coolant 5.

[0049] S6. Control the pump source 1 to emit pump light 2, so that the pump light 2 is amplified by the first-stage laser amplification system and the second-stage laser amplification system in sequence, and then directed from the focusing lens 14 to the target object;

[0050] S7. After completion, turn off all devices and disconnect the power.

[0051] The embodiments described above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A wavelength-tunable multi-medium high-efficiency laser amplification device, characterized in that, It includes a pump source (1), a primary laser amplification system, and a secondary laser amplification system arranged sequentially; The first-stage laser amplification system includes a first pump mirror (15), a first gain medium (4), and a first partial reflector (19) arranged in sequence. The left and right ends of the first pump mirror (15) are respectively positioned facing the pump source (1) and the first gain medium inlet (3) on the first gain medium (4). The first partial reflector (19) is positioned facing the first gain medium outlet (18) on the first gain medium (4), so that the pump light (2) emitted by the pump source (1) passes through the first pump mirror (15) and enters the first gain medium (4), is amplified by the first gain medium (4), and is transmitted to the first partial reflector (19). The first gain medium (4) is wrapped with SiO2 crystal (41), Au thin film (43) and plastic shell (44) in sequence. Nanowires (42) are sandwiched between SiO2 crystal (41) and Au thin film (43). The laser wavelength is tuned by adjusting the film thickness ratio K of SiO2 crystal and Au thin film. The nanowires (42) are made of tungsten diselenide. The secondary laser amplification system includes a second pump mirror (8), a second gain medium (22), and a second partial mirror (24) arranged in sequence. The left and right ends of the second pump mirror (8) are respectively positioned facing the second gain medium inlet (9) on the first partial mirror (19) and the second gain medium (22). The second partial mirror (24) is positioned facing the second gain medium outlet (26) on the second gain medium (22). This allows the first gain laser beam (20) amplified by the primary laser amplification system to pass through the second pump mirror (8) into the second gain medium (22), be amplified by the second gain medium (22), and then transmitted to the second partial mirror (24).

2. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, A first collimating mirror (7) is provided between the first partial reflector (19) and the second pump mirror (8) to collimate the first gain laser beam (20) transmitted from the first partial reflector (19) into parallel light. The second collimating mirror (13) and focusing mirror (14) are arranged sequentially on the right end of the second part of the reflector (24), so that the second gain laser beam (25) transmitted from the second part of the reflector (24) is collimated into parallel light by the second collimating mirror (13) and then focused by the focusing mirror (14).

3. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, The second gain medium (22) is wrapped with a high-reflectivity film (10).

4. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, The first gain medium (4) is placed in the first cooling tank (17) containing coolant (5); The second gain medium (22) is placed in the second cooling tank (23) containing coolant (5); The first cooling tank (17) and the second cooling tank (23) are each provided with an inlet and an outlet for the coolant (5) to enter and exit at any pair of opposite corners.

5. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, The first gain medium (4) is configured as a coil.

6. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, The first gain medium (4) is made of one of germanium-doped quartz, ZBLAN optical fiber, or sulfide. The plastic outer shell (44) is made of thermally conductive material; The material of the second gain medium (22) is one of ND: LuAG ceramic, ND: CaF2 crystal, ND: YAG crystal, Yb: S-FAP crystal, and Yb: YAG; The coolant (5) is one of the following: glycerol-based coolant, ethylene glycol-based coolant, or water-based coolant.

7. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, The first gain medium inlet (3) end face forms an acute or obtuse angle with the horizontal plane; The end face of the second gain medium inlet (9) forms an acute or obtuse angle with the horizontal plane.

8. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 2, characterized in that, A certain distance is set between the first collimating mirror (7) and the first partial reflector (19); and the longitudinal cross-sectional area of ​​the second gain medium (22) is greater than that of the first gain medium (4).

9. The wavelength-tunable multi-medium high-efficiency laser amplification device according to claim 1, characterized in that, The first gain medium (4) has a circular cross-sectional shape; the second gain medium (22) has a circular, square, or rectangular cross-sectional shape.

10. A wavelength-tunable, multi-medium, high-efficiency laser amplification method, characterized in that, The specific steps of using the wavelength-tunable multi-medium high-efficiency laser amplification device according to any one of claims 1-9 are as follows: S1. Based on the required wavelength of the first gain laser beam (20), determine the film thickness ratio K of SiO2 crystal (41) and Au thin film (43), and make SiO2 crystal (41), Au thin film (43) and plastic shell (44) sequentially stacked to wrap the first gain medium (4), and nanowires (42) are sandwiched between SiO2 crystal (41) and Au thin film (43). S2. Place the wrapped first gain medium (4) into the first cooling box (17); S3. Select the appropriate second gain medium (22) according to the wavelength of the first gain laser beam (20), and wrap a high reflection film (10) on the outside of the second gain medium (22). S4. Place the wrapped second gain medium (22) inside the second cooling box (23); S5. Add coolant (5) to the inlets of the first cooling tank (17) and the second cooling tank (23) so that the first cooling tank (17) and the second cooling tank (23) are filled with flowing coolant (5); S6. Control the pump source (1) to emit pump light (2), so that the pump light (2) is amplified by the first-stage laser amplification system and the second-stage laser amplification system in sequence, and then directed to the target object from the focusing lens (14); S7. After completion, turn off all devices and disconnect the power.

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