A large energy stimulated raman laser based on a batten structure

Abstract

The application discloses a kind of big energy stimulated raman laser based on batten structure, belong to laser technology and nonlinear optics field.The laser includes pump source, shaping optical system, batten laser crystal, Q device, resonant cavity and amplification structure.The laser uses batten gain medium and raman crystal, realizes high-efficiency 1 μm pulse laser output by partial end face pumping and polarization double-pass amplification technology;Further utilize external cavity raman resonant cavity to generate stable stimulated raman seed light, and pass through multi-mirror regulation light path, so that seed light and pump light are in batten raman amplification crystal space synchronization, realize high-efficiency stimulated raman amplification.The application effectively solves the problem of poor heat dissipation and significant thermal effect of traditional rod structure, has the advantages of high heat dissipation efficiency, good beam quality, large output energy, strong stability, is suitable for atmospheric laser radar detection, photoelectric countermeasure, spectrum detection, medical treatment and industrial processing and other fields.

Description

Technical Field

[0001] This invention belongs to the fields of laser technology and nonlinear optics, specifically relating to a high-energy stimulated Raman laser based on a slab structure. Background Technology

[0002] Traditional lasers are limited by the energy level transitions of the gain medium, with most output wavelengths concentrated in the 1μm band, making it difficult to cover the broad ultraviolet to mid-infrared range. Stimulated Raman scattering (SRS) technology, however, can effectively extend the laser wavelength by utilizing nonlinear frequency conversion. Stimulated Raman lasers generate Stokes light with a certain frequency shift through the interaction between the pump light and the Raman medium, which has important application value in fields such as spectroscopic detection, biomedicine, and industrial processing.

[0003] Currently, research on high-energy stimulated Raman lasers mainly focuses on gain media, 1μm pump sources, and overall configuration. Regarding gain media, solid Raman crystals (such as KGW and BaWO4) have attracted much attention due to their high Raman gain, good thermal conductivity, and stable mechanical properties. However, limited by the inelastic scattering effect of stimulated Raman, these crystals accumulate significant heat power under high-power pumping. Traditional rod-shaped Raman crystals have low heat dissipation efficiency, leading to severe thermal lensing and thermal stress birefringence, significantly degrading beam quality and conversion efficiency. A more ideal approach is to use slab-shaped stimulated Raman crystals with a one-dimensional linear distribution of the 1μm pump source spot. As for the 1μm pump source, traditional high-energy 1μm pump sources are all circular... Symmetrical Gaussian beam distribution, shaped using methods such as optical field mapping, is costly and technically complex. Furthermore, the 1μm incident spot size and distribution have strict requirements, and circularly symmetric Gaussian shaping requires additional shaping elements to achieve a linear spot. Regarding overall configuration, traditional external cavity Raman lasers are simple but have limited capacity to withstand 1μm pump power. Excessive pump power injection makes resonant cavity design difficult, and the extremely high power density within the cavity can easily damage optical components. Internal cavity Raman lasers offer greater flexibility in achieving complex wavelength transformations, but their resonant cavity design is more complex, making it difficult to achieve high-energy output, limiting output power to the hundreds of μJ level. In summary, existing technologies struggle to simultaneously meet the multiple requirements of high energy, high beam quality, high stability, and efficient heat dissipation, thus restricting the practical application of stimulated Raman lasers in high-end fields such as atmospheric lidar detection.

[0004] To address the aforementioned bottlenecks, there is an urgent need to develop a novel laser structure that can effectively manage thermal load, improve heat dissipation efficiency, ensure pump coupling accuracy, and achieve stable high-energy Raman laser output. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a high-energy stimulated Raman laser based on a slab structure, employing a diode array pumped with Nd-doped laser. 3+A 1μm laser beam is generated using a slab-shaped gain medium. The pump light output from the diode array is homogenized and shaped along the slow axis, precisely matching the end face of the slab crystal, effectively improving pump efficiency. A 1μm linear spot is directly generated based on the hybrid cavity structure. Based on the polarization characteristics of the light and the bi-level slab structure, polarization two-way gain technology is used to further enhance the 1μm pump energy, providing a foundation for high-energy stimulated Raman laser output. Due to the one-dimensional homogenization of the 1μm pump source, the internal temperature distribution of the slab Raman crystal is one-dimensionally symmetrical, with a temperature gradient only in the thickness direction, eliminating the thermally induced birefringence problem caused by the two-dimensional temperature gradient. The slab Raman crystal has a large upper and lower surface area, allowing for efficient heat dissipation by direct welding to a high-efficiency heat sink. This invention utilizes an amplifier structure that injects Raman seed light and 1μm pump light together into the next stage slab Raman crystal. The optical path is designed to achieve precise spatiotemporal coupling between the two. Based on stimulated Raman amplification, the energy of the Raman seed light is further enhanced, effectively separating the stimulated Raman seed light from the high-energy amplification process. Ultimately, a high-energy and high-beam-quality Raman laser output is obtained. The slab size can also be expanded laterally, effectively reserving upgrade space for further energy output enhancement without changing the configuration.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A high-energy stimulated Raman laser based on a slat structure includes:

[0008] Pump source module, used to generate pump light;

[0009] A 1μm pulsed laser generation module is used to convert the pump light into a 1μm pulsed laser. It includes a first slab laser crystal, a slab birefringent crystal, and an electro-optic Q-switching device arranged sequentially along the optical path.

[0010] A 1μm pulsed laser amplification module is used to amplify the energy of the 1μm pulsed laser. It adopts a polarization two-way amplification structure and includes at least one amplification unit. Each amplification unit includes a slab laser crystal, a λ / 4 waveplate and a dichroic mirror.

[0011] Stimulated Raman seed light generation module, used to generate stimulated Raman seed light using amplified 1μm pulsed laser, includes an external cavity resonator composed of a first stimulated Raman cavity mirror, a slab stimulated Raman crystal, and a second stimulated Raman cavity mirror;

[0012] The stimulated Raman laser amplification module is used to delay the amplified 1μm pulsed laser. The generated stimulated Raman seed light and the delayed laser converge in the slab stimulated Raman amplification crystal to achieve spatiotemporal synchronization, and the laser amplification output is achieved through stimulated Raman scattering effect.

[0013] The first slab laser crystal, the slab laser crystal, the slab stimulated Raman crystal, and the slab stimulated Raman amplification crystal are all slab-shaped structures.

[0014] Furthermore, the 1μm pulsed laser generation module includes a first pump-shaping optical system, a first dichroic mirror, a first slab laser crystal, a slab-structured α-BBO birefringent crystal, an electro-optic Q-switching device, and an output cavity mirror arranged sequentially along the optical path.

[0015] Furthermore, the first pump-shaping optical system pumps and shapes the pump light, which is then incident on the first dichroic mirror. The pump light passing through the first dichroic mirror is injected into the first slab laser crystal. The first slab laser crystal absorbs pump light of a specific wavelength, causing the activated ions inside the crystal to achieve population inversion. In the resonant cavity formed by the first dichroic mirror and the output cavity mirror, photons continuously oscillate and pass back and forth through the first slab crystal, accumulating energy to generate a stable 1μm pulsed laser.

[0016] Furthermore, an α-BBO birefringent crystal is placed after the first slab laser crystal to convert the laser into a linearly polarized laser. The electro-optic Q-switching device performs unipolar electro-optic Q-switching on the linearly polarized laser so that the linearly polarized laser accumulates energy in the resonant cavity and releases to form a 1μm pulse laser with high peak power.

[0017] Furthermore, the 1μm pulsed laser generating module and the 1μm pulsed laser amplifying module include an isolator, a first reflecting mirror, a first shaping cavity mirror, a second shaping cavity mirror, a second reflecting mirror, a third shaping cavity mirror, a fourth shaping cavity mirror, and a fifth shaping cavity mirror arranged sequentially along the optical path.

[0018] Furthermore, the isolator is used to ensure lossless transmission of 1μm pulsed laser; the first reflecting mirror, the first shaping cavity mirror, the second shaping cavity mirror, the second reflecting mirror, the third shaping cavity mirror, the fourth shaping cavity mirror, and the fifth shaping cavity mirror are used to shape the laser about to enter the 1μm pulsed laser amplification module in the slow axis and fast axis directions.

[0019] Furthermore, the 1μm pulsed laser amplification module includes, sequentially arranged along the optical path, a first thin-film polarizer, a second slab laser crystal, a first λ / 4 waveplate, a second dichroic mirror, a second pump-shaping optical system, a second stacked pump module, a sixth shaping cavity mirror, a second thin-film polarizer, a third slab laser crystal, a second λ / 4 waveplate, a third dichroic mirror, a third pump-shaping optical system, and a third stacked pump module.

[0020] Furthermore, the 1μm pulsed laser, as a seed source, enters the second slab laser crystal through the first thin-film polarizer and interacts with the inverted particles within the crystal to achieve the first energy amplification. After being converted from linearly polarized light to circularly polarized light by the first λ / 4 waveplate, it is reflected by the second dichroic mirror. The circularly polarized light, with its propagation direction reversed and polarization rotation reversed, passes through the first λ / 4 waveplate again and is converted into linearly polarized light. It then passes through the second slab laser crystal again to achieve the second energy amplification.

[0021] The laser then reaches the first thin-film polarizer, which reflects the linearly polarized light by 45° to change its propagation direction. After passing through the sixth shaping cavity mirror, it reaches the second thin-film polarizer, which reflects the linearly polarized light by 45° and injects it into the third slab laser crystal to achieve the third energy amplification. Subsequently, the laser passing through the second λ / 4 waveplate is reflected by the third dichroic mirror and returns to the third slab laser crystal along the original path after passing through the second λ / 4 waveplate, achieving the fourth energy amplification. Finally, it is output through the third dichroic mirror.

[0022] Furthermore, the amplified 1μm pulsed laser is refracted 45° by the third reflecting mirror and propagates along the optical path. It is then split into two paths by a beam splitter. One path enters the stimulated Raman seed light generation module, and the other path enters the stimulated Raman laser amplification module. The laser entering the stimulated Raman seed light generation module oscillates back and forth in the external cavity resonant cavity, accumulating energy until a stable Raman seed light output is formed. Finally, it is injected into the slab stimulated Raman amplification crystal through the second stimulated Raman cavity mirror, the fourth reflecting mirror, and the fourth dichroic mirror.

[0023] Furthermore, in the stimulated Raman laser amplification module, another laser beam passes sequentially through the fifth, sixth, seventh, eighth, ninth, and fourth dichroic mirrors to reach the slab stimulated Raman amplification crystal and merges with the Raman seed light.

[0024] The beneficial effects of this invention are as follows:

[0025] In this invention, the gain medium is entirely composed of slab-shaped crystals. The geometry of the slab-shaped crystals ensures a temperature gradient only along the thickness direction, effectively suppressing thermal effects. Furthermore, the large surface area of ​​the slab-shaped crystals allows for direct welding to a high-efficiency heat sink, achieving highly efficient heat dissipation. This structurally solves the problem of low heat dissipation efficiency of traditional rod-shaped crystals, ensuring the output stability of high-energy lasers. In the pump source design, a diode array pump is used to pump Nd-doped lasers. 3+A 1μm laser is generated using a slab-shaped gain medium. Through precise coupling and polarization control of the pump light, and utilizing polarization-based two-way gain amplification technology, a high-energy 1μm pulsed laser is obtained. Simultaneously, the rectangular beam output from the slab-shaped pump source is highly compatible with the absorption characteristics of the slab-shaped Raman medium, improving energy coupling efficiency and thus providing sufficient and matched pump energy for high-energy stimulated Raman laser output. In terms of cavity structure, an amplified cavity structure is adopted where the Raman seed light and pump light are co-injected into the Raman crystal. Multiple mirrors precisely control the optical path, achieving a high degree of synchronization between the pump light and seed light in both the temporal and spatial domains. Utilizing the efficient gain accumulation advantage of the amplified cavity structure, combined with the efficient heat dissipation capability of the slab gain medium, efficient and stable high-energy stimulated Raman laser output is ultimately achieved. Attached Figure Description

[0026] Figure 1 This is a block diagram of a high-energy stimulated Raman laser based on a slat structure according to the present invention.

[0027] Figure label:

[0028] 1. First stacked pump module; 2. First pump shaping optical system; 3. First dichroic mirror; 4. First slab laser crystal; 5. α-BBO birefringent crystal; 6. Electro-optic Q-switching device; 7. Output cavity mirror; 8. Isolator; 9. First reflecting mirror; 10. First shaping cavity mirror; 11. Second shaping cavity mirror; 12. Second reflecting mirror; 13. Third shaping cavity mirror; 14. Fourth shaping cavity mirror; 15. Fifth shaping cavity mirror; 16. First thin-film polarizer; 17. Second slab laser crystal; 18. First λ / 4 waveplate; 19. Second dichroic mirror; 20. Second pump shaping optical system; 21. Second stacked pump module. 21. Sixth Shaping Cavity Mirror; 22. Second Thin-Film Polarizer; 23. Third Slab Laser Crystal; 24. Second λ / 4 Waveplate; 25. Third Dichroic Mirror; 26. Third Pump Shaping Optical System; 27. Third Stacked Pump Module; 28. Third Reflector; 29. ​​Beam Splitter; 30. First Stimulated Raman Cavity Mirror; 31. Slab Stimulated Raman Crystal; 32. Second Stimulated Raman Cavity Mirror; 33. Fourth Reflector; 34. Fifth Reflector; 35. Sixth Reflector; 36. Seventh Reflector; 37. Eighth Reflector; 38. Ninth Reflector; 39. Fourth Dichroic Mirror; 40. Slab Stimulated Raman Magnifying Crystal; 41. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] As attached Figure 1As shown, a high-energy stimulated Raman laser based on a slab structure according to the present invention includes a first stacked pump module 1, a first pump shaping optical system 2, a first dichroic mirror 3, a first slab laser crystal 4, a slab-structured α-BBO birefringent crystal 5, an electro-optic Q-switching device 6, an output cavity mirror 7, an isolator 8, a first reflecting mirror 9, a first shaping cavity mirror 10, a second shaping cavity mirror 11, a second reflecting mirror 12, a third shaping cavity mirror 13, a fourth shaping cavity mirror 14, a fifth shaping cavity mirror 15, a first thin-film polarizer (TFP) 16, a second slab laser crystal 17, a first λ / 4 waveplate 18, a second dichroic mirror 19, and a second... The optical system comprises: a pump-shaping optical system 20, a second stacked pump module 21, a sixth shaping cavity mirror 22, a second thin-film polarizer 23, a third slab laser crystal 24, a second λ / 4 waveplate 25, a third dichroic mirror 26, a third pump-shaping optical system 27, a third stacked pump module 28, a third reflecting mirror 29, a beam splitter 30, a first stimulated Raman cavity mirror 31, a slab stimulated Raman crystal 32, a second stimulated Raman cavity mirror 33, a fourth reflecting mirror 34, a fifth reflecting mirror 35, a sixth reflecting mirror 36, a seventh reflecting mirror 37, an eighth reflecting mirror 38, a ninth reflecting mirror 39, a fourth dichroic mirror 40, and a slab stimulated Raman amplifying crystal 41. All components are mounted on the same plane and arranged sequentially according to the optical path transmission order; their order cannot be changed.

[0031] The high-energy stimulated Raman laser based on a slab structure of the present invention, when applied, proceeds in the following four steps: generation of a 1μm pulse laser, amplification of the 1μm pulse laser, generation of stimulated Raman laser, and amplification of stimulated Raman laser:

[0032] Step 1, generation of 1μm pulsed laser; includes: pump light emitted by the first stacked pump module 1 is shaped and collimated by the first pump shaping optical system 2, and then injected into the first slab laser crystal 4 through the first dichroic mirror 3 to excite Nd2 lasers. 3+ Ion stimulated emission generates a 1μm continuous laser. Subsequently, the continuous laser is converted into a 1μm pulsed laser by passing through a lath-structured α-BBO birefringent crystal 5 and an electro-optic Q-switching device 6 (a lath-structured unipolar Q-switching device).

[0033] Step 2, amplification of the 1μm pulsed laser; includes: amplifying the energy of the 1μm pulsed laser using polarization double-pass amplification. The first λ / 4 waveplate 18 works in conjunction with the second slab laser crystal 17, allowing the seed source to pass back and forth within the resonant cavity through the second slab laser crystal 17, achieving two energy amplifications; the second λ / 4 waveplate 25 works in conjunction with the third slab laser crystal 24, allowing the seed source to pass through the third slab laser crystal 24 within the resonant cavity, achieving two more energy amplifications, for a total of four energy gains, ultimately outputting a high-energy 1μm pulsed laser.

[0034] Step 3, Stimulated Raman Laser Generation; includes: a resonant cavity consisting of a first stimulated Raman cavity mirror 31, a slab stimulated Raman crystal 32, and a second stimulated Raman cavity mirror 33; a 1μm pulsed laser is injected into the slab stimulated Raman crystal 32 as pump light to generate an initial Raman laser; the initially generated stimulated Raman laser oscillates back and forth in the resonant cavity, accumulating energy until the stimulated Raman laser is strong enough to form a stable stimulated Raman seed light;

[0035] Step 4, stimulated Raman laser amplification; includes: the stable stimulated Raman seed light and the second pump light are combined in the slab stimulated Raman amplification crystal 41, the Raman seed light and the pump light are stimulated Raman scattering in the Raman medium to achieve Raman laser amplification, and the pump light and the seed light can be precisely controlled by multiple mirrors to ensure that the pump light and the seed light maintain a high degree of synchronization in the time domain and space, so as to achieve efficient stimulated Raman laser amplification.

[0036] During laser generation, the first stacked pump module 1 acts as the pump source, emitting pump light of a specific wavelength that enters the first pump shaping optical system 2. The first pump shaping optical system 2 shapes the pump light for incident on the first dichroic mirror 1. The first dichroic mirror 1 has selective transmission and reflection characteristics, exhibiting high transmittance for the pump light wavelength and high reflectance for the laser wavelength generated by the first slab laser crystal 4, thus achieving separation of the pump light and the laser. The pump light passing through the first dichroic mirror 1 is injected into the first slab laser crystal 4. At this time, the first slab laser crystal 4 absorbs the pump light of the specific wavelength, causing the activated ions inside the crystal to achieve population inversion. Simultaneously, within the resonant cavity formed by the first dichroic mirror 3 and the output cavity mirror 7, photons continuously oscillate and pass through the first slab laser crystal 4, continuously accumulating energy to generate a stable 1μm laser. When a 1μm laser beam is incident on a lath-structured α-BBO birefringent crystal 5, the crystal splits the laser beam into an extraordinary (e) beam parallel to the optical axis and an ordinary (o) beam perpendicular to the optical axis. The refractive index of the e beam changes with the propagation direction, while the refractive index of the o beam remains constant. A mechanical aperture allows only the o beam to pass through, while the e beam, due to its changing refractive index, will spatially drift away and be blocked by the aperture. The lath-structured α-BBO birefringent crystal 5 is small in size and highly reliable. The generated linearly polarized laser is then subjected to unipolar electro-optic Q-switching via the lath structure, allowing a large amount of energy to accumulate within the resonant cavity and be released in a concentrated burst of high-peak-power pulsed laser light over tens of nanoseconds.

[0037] The generated 1μm pulsed laser light passes through isolator 8, first reflector 9, first shaping cavity mirror 10, second shaping cavity mirror 11, second reflector 12, third shaping cavity mirror 13, fourth shaping cavity mirror 14, and fifth shaping cavity mirror 15, and is injected into the 1μm pulsed laser amplification system through first thin-film polarizer 16. The 1μm pulsed laser amplification system includes first thin-film polarizer 16, second slab laser crystal 17, first λ / 4 waveplate 18, second dichroic mirror 19, second pump shaping optical system 20, second stacked pump module 21, sixth shaping cavity mirror 22, second thin-film polarizer 23, third slab laser crystal 24, second λ / 4 waveplate 25, third dichroic mirror 26, third pump shaping optical system 27, and third stacked pump module 28. Isolator 8 allows the linearly polarized light generated by the oscillator stage to pass through the subsequent amplification system without loss, and effectively blocks the reverse light, ensuring that the high-energy laser light generated by the subsequent amplification system will not damage the optical components before isolator 8. After long-distance transmission, the laser beam output from the oscillator naturally expands beyond the area of ​​the second slab laser crystal 17, causing some energy to be unabsorbed by the gain medium. The core function of the first shaping cavity mirror 10, second shaping cavity mirror 11, second reflecting mirror 12, third shaping cavity mirror 13, fourth shaping cavity mirror 14, and fifth shaping cavity mirror 15 is to control the laser beam entering the amplification system of the 1μm pulsed laser through a combination of shaping cavity mirrors with different curvatures and positions. The slow-axis and fast-axis directions of the beam are shaped separately. Through wavefront correction, divergence angle compression, and preservation of high beam quality, the beam is precisely coupled and injected into the second slab laser crystal 17, allowing the subsequent 1μm pulsed laser amplification system to efficiently increase the laser energy, thereby providing the pump source energy required for high-energy stimulated Raman laser output.

[0038] During the amplification of the 1μm pulsed laser, a polarization-based double-pass amplification method is used to further amplify the energy of the 1μm pulsed laser. The second stacked pump module 21 emits pump light, which, after being optimized into a uniform rectangular spot by the second pump shaping optical system 20, enters the crystal through the second dichroic mirror 19. The second dichroic mirror 19 has selective transmission and reflection characteristics, exhibiting high transmittance for the pump light wavelength and high reflectance for the wavelength generated by the laser crystal. This ensures that the pump light can be efficiently coupled into the second slab laser crystal 17, exciting the activated ions in the second slab laser crystal 17 from the ground state to a higher energy level, forming population inversion and providing the prerequisite for laser amplification. The oscillator generates 1μm linearly polarized light as a seed source, which enters the amplification system of the 1μm pulsed laser through the first thin-film polarizer 16. The seed light enters the second slab laser crystal 17 and interacts with the inverted particles within the crystal, achieving the first energy amplification. After passing through the first λ / 4 waveplate 18, the linearly polarized light is converted into circularly polarized light. Reflected by the second dichroic mirror 19, its propagation direction reverses, resulting in a reversal of polarization rotation (e.g., left-handed becomes right-handed). The light returns along its original path and passes through the first λ / 4 waveplate 18 again, becoming linearly polarized. It then passes through the second slab laser crystal 17, achieving a second, highly efficient energy amplification, doubling the energy utilization rate. The laser then reaches the first thin-film polarizer 16, which reflects the linearly polarized light at a 45° angle, changing its propagation direction. The sixth shaping cavity mirror 22 further optimizes the beam uniformity, reducing beam distortion during amplification. The shaped laser then reaches the second thin-film polarizer 23, which reflects the linearly polarized light at a 45° angle and injects it into the third slab laser crystal 24. Within the third slab laser crystal 24, the laser undergoes a third energy amplification, further increasing its energy. The laser light passing through the second λ / 4 waveplate 25 is then reflected by the third dichroic mirror 26 and returns to the laser crystal along the original path after passing through the second λ / 4 waveplate 25 again, amplifying its energy for the fourth time before returning to the third dichroic mirror 26. The resulting high-energy laser light is then directly output. The first λ / 4 waveplate 18 works in conjunction with the second slab laser crystal 17, allowing the seed source to pass through the second slab laser crystal 17 twice within the resonant cavity, achieving two energy amplifications. Similarly, the second λ / 4 waveplate 25 works in conjunction with the third slab laser crystal 24, allowing the seed source to pass through the third slab laser crystal 24 twice within the resonant cavity, resulting in a total of four energy amplifications and ultimately outputting a high-energy 1μm pulsed laser. The first λ / 4 waveplate 18 and the second λ / 4 waveplate 25, by converting linearly polarized light to circularly polarized light, ensure that the laser light undergoes two round trips within each of the two slab crystals, resulting in a total of four energy amplifications. This final output of a high-energy 1μm pulsed laser provides the foundation for subsequent stimulated Raman laser output.

[0039] The high-energy 1μm pulsed laser output from the second thin-film polarizer 23 is refracted 45° by the third reflecting mirror 29 and propagates along the optical path. The 1μm pulsed laser is split into two paths by the beam splitter 30. The first path is used to generate Raman seed light, which passes through the first stimulated Raman cavity mirror 31, the slab stimulated Raman crystal 32, the second stimulated Raman cavity mirror 33, and is refracted by the fourth reflecting mirror 34 and the fourth dichroic mirror 40 to reach the slab stimulated Raman amplification crystal 41. The second path passes through the fifth reflecting mirror 35, the sixth reflecting mirror 36, the seventh reflecting mirror 37, the eighth reflecting mirror 38, the ninth reflecting mirror 39, and the fourth dichroic mirror 40 to reach the slab stimulated Raman amplification crystal 41 and merge with the Raman seed light to work synergistically. Finally, the high-energy stimulated Raman laser is output through the slab stimulated Raman amplification crystal 41.

[0040] In the process of stimulated Raman laser generation, a high-energy 1μm pulsed laser is used as the pump light. It passes through a beam splitter 30 and firstly through a first stimulated Raman cavity mirror 31. The first stimulated Raman cavity mirror 31 has selective transmission and reflection characteristics, exhibiting high transmittance for the 1μm pump light and high reflectivity for the stimulated Raman laser. After passing through the first stimulated Raman cavity mirror 31 and entering the slab stimulated Raman crystal 32, the pump light is converted into stimulated Raman laser light due to the SRS effect, and then reaches the second stimulated Raman cavity mirror 33. The first stimulated Raman cavity mirror 31, the slab stimulated Raman crystal 32, and the second stimulated Raman cavity mirror 33 form a resonant cavity. The initially generated Raman laser light oscillates back and forth within the resonant cavity, accumulating energy until the stimulated Raman laser light is sufficiently strong, forming a stable Raman seed light output. The stable Raman seed light passes through the second stimulated Raman cavity mirror 33, then through a fourth reflecting mirror 34 and a fourth dichroic mirror 40 to change the light path direction, and finally injects into the slab stimulated Raman amplification crystal 41.

[0041] The stimulated Raman laser amplification process mainly relies on the combined action of a stable Raman seed light, a second pump light, and a slab-type stimulated Raman amplification crystal 41. In principle, Raman amplification is achieved through stimulated Raman scattering of the seed light and pump light within the Raman medium. The Raman amplification process is illustrated by the following formula: ,in It is the intensity of the incident seed light when it has traveled a distance z. The intensity of the Raman pump light. The gain coefficient of the Raman medium is denoted as . As can be seen from the formula, the intensity of the pump light and the Raman gain coefficient of the Raman medium directly affect the amplification of the seed light. During Raman amplification, the pump light must participate in the entire amplification process. Therefore, the pump light and the seed light must maintain a high degree of synchronization in both the temporal and spatial domains to ensure efficient stimulated Raman amplification. Using a fifth mirror 35, a sixth mirror 36, a seventh mirror 37, an eighth mirror 38, and a ninth mirror 39, multiple mirrors are used to adjust the optical path difference, ensuring that the Raman seed light and the second pump light arrive at the slab stimulated Raman amplification crystal 41 simultaneously through the fourth dichroic mirror 40. This avoids the second pump light arriving first and wasting energy, or the Raman seed light arriving first and failing to amplify. The fourth dichroic mirror 40 has selective transmission and reflection characteristics, exhibiting high transmittance for the pump light wavelength and high reflectance for the stimulated Raman seed light, reflecting the stimulated Raman seed light at a 45° angle while simultaneously transmitting the pump light. Multiple mirrors allow for precise control of the incident angle and position of the two beams, ensuring they propagate in the same region and direction within the slab-stimulated Raman amplification crystal 41. This satisfies the conditions for stimulated Raman amplification, guaranteeing a high degree of synchronization between the pump light and the seed light in both time and space. Ultimately, the energy of the second pump light is efficiently amplified through the SRS effect, resulting in high-energy stimulated Raman laser output.

[0042] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-energy stimulated Raman laser based on a slat structure, characterized in that, include: Pump source module, used to generate pump light; A 1μm pulsed laser generation module is used to convert the pump light into a 1μm pulsed laser. It includes a first slab laser crystal, a slab birefringent crystal, and an electro-optic Q-switching device arranged sequentially along the optical path. A 1μm pulsed laser amplification module is used to amplify the energy of the 1μm pulsed laser. It adopts a polarization two-way amplification structure and includes at least one amplification unit. Each amplification unit includes a slab laser crystal, a λ / 4 waveplate and a dichroic mirror, as well as a stacked pump module. The stacked pump module emits pump light into the slab laser crystal, which excites the activated ions in the crystal from the ground state to a high energy level, forming a population inversion that provides the prerequisite for laser amplification. Stimulated Raman seed light generation module, used to generate stimulated Raman seed light using amplified 1μm pulsed laser, includes an external cavity resonator composed of a first stimulated Raman cavity mirror, a slab stimulated Raman crystal, and a second stimulated Raman cavity mirror; The stimulated Raman laser amplification module is used to delay the amplified 1μm pulsed laser. The generated stimulated Raman seed light and the delayed laser converge in the slab stimulated Raman amplification crystal to achieve spatiotemporal synchronization, and the laser amplification output is achieved through stimulated Raman scattering effect. The first slab laser crystal, the slab laser crystal, the slab stimulated Raman crystal, and the slab stimulated Raman amplification crystal are all slab-shaped structures.

2. The high-energy stimulated Raman laser based on a slat structure according to claim 1, characterized in that, The 1μm pulsed laser generation module includes a first pump-shaping optical system, a first dichroic mirror, a first slab laser crystal, an α-BBO birefringent crystal with a slab structure, an electro-optic Q-switching device, and an output cavity mirror arranged sequentially along the optical path.

3. A high-energy stimulated Raman laser based on a slat structure according to claim 2, characterized in that, The first pump-shaping optical system pumps and shapes the pump light, which is then incident on the first dichroic mirror. The pump light passing through the first dichroic mirror is injected into the first slab laser crystal. The first slab laser crystal absorbs the injected pump light, causing the activated ions inside the crystal to achieve population inversion. In the resonant cavity formed by the first dichroic mirror and the output cavity mirror, photons continuously oscillate and pass back and forth through the first slab crystal, accumulating energy to generate a stable 1μm pulsed laser.

4. A high-energy stimulated Raman laser based on a slat structure according to claim 3, characterized in that, An α-BBO birefringent crystal is placed after the first slab laser crystal to convert the laser into a linearly polarized laser. The electro-optic Q-switching device performs unipolar electro-optic Q-switching on the linearly polarized laser so that the linearly polarized laser accumulates energy in the resonant cavity and releases to form a 1μm pulse laser with high peak power.

5. A high-energy stimulated Raman laser based on a slat structure according to claim 1, characterized in that, The 1μm pulsed laser generating module and the 1μm pulsed laser amplifying module include an isolator, a first reflector, a first shaping cavity mirror, a second shaping cavity mirror, a second reflector, a third shaping cavity mirror, a fourth shaping cavity mirror, and a fifth shaping cavity mirror arranged sequentially along the optical path.

6. A high-energy stimulated Raman laser based on a slat structure according to claim 5, characterized in that, The isolator is used to ensure the lossless transmission of 1μm pulsed laser; the first reflecting mirror, the first shaping cavity mirror, the second shaping cavity mirror, the second reflecting mirror, the third shaping cavity mirror, the fourth shaping cavity mirror, and the fifth shaping cavity mirror are used to shape the laser that is about to enter the 1μm pulsed laser amplification module in the slow axis and fast axis directions.

7. A high-energy stimulated Raman laser based on a slat structure according to claim 1, characterized in that, The 1μm pulsed laser amplification module includes, sequentially arranged along the optical path, a first thin-film polarizer, a second slab laser crystal, a first λ / 4 waveplate, a second dichroic mirror, a second pump-shaping optical system, a second stacked pump module, a sixth shaping cavity mirror, a second thin-film polarizer, a third slab laser crystal, a second λ / 4 waveplate, a third dichroic mirror, a third pump-shaping optical system, and a third stacked pump module.

8. A high-energy stimulated Raman laser based on a slat structure according to claim 7, characterized in that, A 1μm pulsed laser, as a seed source, enters the second slab laser crystal through a first thin-film polarizer and interacts with the inverted particles within the crystal to achieve the first energy amplification. After passing through a first λ / 4 waveplate to convert the linearly polarized light into circularly polarized light, it is reflected by a second dichroic mirror, with the propagation direction reversed and the polarization rotation reversed. The circularly polarized light then passes through the first λ / 4 waveplate again, is converted into linearly polarized light, and passes through the second slab laser crystal again to achieve the second energy amplification. The laser then reaches the first thin-film polarizer, which reflects the linearly polarized light by 45° to change its propagation direction. After passing through the sixth shaping cavity mirror, it reaches the second thin-film polarizer, which reflects the linearly polarized light by 45° and injects it into the third slab laser crystal to achieve the third energy amplification. Subsequently, the laser passing through the second λ / 4 waveplate is reflected by the third dichroic mirror and returns to the third slab laser crystal along the original path after passing through the second λ / 4 waveplate, achieving the fourth energy amplification. Finally, it is output through the third dichroic mirror.

9. A high-energy stimulated Raman laser based on a slat structure according to claim 1, characterized in that, The amplified 1μm pulsed laser is refracted 45° by the third reflecting mirror and propagates along the optical path. It is then split into two paths by a beam splitter. One path enters the stimulated Raman seed light generation module, and the other path enters the stimulated Raman laser amplification module. The laser entering the stimulated Raman seed light generation module oscillates back and forth in the external cavity resonant cavity, accumulating energy until a stable Raman seed light output is formed. Finally, it is injected into the slab stimulated Raman amplification crystal through the second stimulated Raman cavity mirror, the fourth reflecting mirror, and the fourth dichroic mirror.

10. A high-energy stimulated Raman laser based on a slat structure according to claim 7, characterized in that, In the stimulated Raman laser amplification module, another laser beam passes sequentially through the fifth, sixth, seventh, eighth, ninth, and fourth dichroic mirrors to reach the slab stimulated Raman amplification crystal and merges with the Raman seed light.

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