A high-power single-frequency laser based on a fiber-slab hybrid structure.

Abstract

This invention provides an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure, belonging to the field of solid-state laser technology. It includes an all-solid-state continuous single-frequency seed module, a fiber pulse modulation module, a fiber pre-amplification module, a slab laser pre-amplification module, a slab laser main amplification module, and a frequency doubling module, arranged sequentially. Both the slab laser pre-amplifier and the slab laser main amplifier in this invention utilize a multi-pass amplification designed with the principle of spherical aberration self-compensation to compensate for thermal aberrations generated by the slab laser, thereby improving beam quality. Furthermore, this invention uses discrete mirror groups instead of complete amplifier cavity mirrors, effectively suppressing spontaneous emission and parasitic oscillations during amplifier operation, resulting in a single-frequency pulsed laser with excellent beam quality in the near-hundred mJ range, which can meet the requirements for lidar detection or industrial applications.

Description

Technical Field

[0001] This invention relates to the field of solid-state laser technology, and more specifically to an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure. Background Technology

[0002] High-power single-frequency lasers have significant application value in precision machining, optical communication, remote sensing, and defense technology. Traditionally, single-frequency lasers are primarily achieved using fiber lasers or solid-state slab lasers. Fiber lasers, with their excellent beam quality, high optical-to-optical conversion efficiency (up to 25%), and compact structure, have become the mainstream choice for high-precision applications. However, their output power is limited by the nonlinear effects of optical fibers (such as stimulated Raman scattering and photon darkening), making it difficult to break through the kilowatt-level limitation. On the other hand, while solid-state slab lasers (such as Yb:YAG slab structures) can achieve high average power output, their large size, complex thermal management, and poor single-frequency stability make it difficult to meet the requirements of high beam quality and miniaturization. In existing technologies, the performance limitations of both types of lasers make it difficult to simultaneously achieve high power and single-frequency characteristics, necessitating a novel structure to overcome the combined bottleneck of power, stability, and compactness. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure. This system outputs a pulsed laser with a single pulse energy of up to nearly 100 mJ, narrow pulse width, adjustable repetition frequency (50 Hz to 10 kHz), compact structure, and excellent beam quality, which can be widely used in the field of lidar detection.

[0004] The technical solution of the present invention is: an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure, comprising an all-solid-state continuous single-frequency seed module, a fiber pulse modulation module, a fiber pre-amplification module, a slab laser pre-amplification module, a slab laser main amplification module, and a frequency doubling module arranged sequentially;

[0005] The all-solid-state continuous single-frequency seed module generates a single-frequency continuous laser output to the fiber pulse modulation module. The fiber pulse modulation module modulates the incident single-frequency continuous laser pulse into a single-frequency high-repetition-rate pulse laser and outputs it to the fiber pre-amplification module. The fiber pre-amplification module amplifies the incident single-frequency high-repetition-rate laser and outputs it to the slab laser pre-amplification module. The slab laser pre-amplification module amplifies the incident single-frequency high-repetition-rate laser and outputs it to the slab laser main amplification module. The slab laser main amplification module receives the single-frequency high-repetition-rate laser, amplifies it further, and outputs it to the frequency doubling module. The frequency doubling module receives the single-frequency high-repetition-rate laser, multiplies its frequency, and outputs the laser.

[0006] Compared with the prior art, the advantages of this invention are as follows:

[0007] This invention achieves a synergistic improvement in high power and single-frequency characteristics. Through fiber pulse modulation and fiber pre-amplification, combined with the high-power amplification capability of a slab amplifier, it retains the narrow linewidth and high coherence characteristics of single-frequency lasers while overcoming the power limitations of traditional fiber lasers. Furthermore, it optimizes efficient heat dissipation and preheating management. The slab amplifier employs microchannel water cooling technology to effectively reduce the crystal thermal lensing effect, avoiding beam quality degradation caused by thermal distortion in traditional slab lasers. Finally, it achieves adjustable repetition frequency. By pulse-modulating the input continuous laser using a fiber-type electro-optic modulator, an adjustable repetition frequency of 50Hz to 10kHz is achieved. This invention provides an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure. Both the slab laser pre-amplifier and the slab laser main amplifier in this invention utilize multi-pass amplification designed with the spherical aberration self-compensation principle to compensate for thermally induced aberrations generated by the slab laser, thereby improving beam quality. Furthermore, this invention uses discrete mirror groups to replace the complete amplifier cavity mirror, which effectively suppresses spontaneous emission and parasitic oscillations during amplifier operation, and can obtain a single-frequency pulse laser with excellent beam quality in the order of nearly 100 mJ, which can meet the requirements of lidar detection or industrial applications. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an all-solid-state high-power single-frequency laser based on a fiber-slat hybrid structure provided in an embodiment of the present invention;

[0009] Figure 2 This is a measured light spot image output by the fiber optic pre-amplification module provided in this embodiment.

[0010] The attached diagram is labeled as follows: 1. All-solid-state continuous single-frequency seed module; 2. Fiber pulse modulation module; 3. Fiber pre-amplification module; 4. Slab laser pre-amplification module; 5. Slab laser main amplification module; 6. Frequency doubling module; 7. Polarization-maintaining fiber coupler; 8. Polarization-maintaining fiber collimator; 9. Shaping module; 10. Reflector; 11. Discrete cavity mirror; 12. Discrete cavity mirror; 13. Discrete cavity mirror; 14. Laser crystal; 15. Cavity mirror; 16. Reflector; 17. Shaping mirror group; 18. Reflector. 19. Discrete cavity mirror 21. Discrete cavity mirror 22. Discrete cavity mirror 23. Discrete cavity mirror 24. Laser crystal 25. Cavity mirror 26. Shaping mirror assembly 27. Discrete cavity mirror 28. Discrete cavity mirror 29. Discrete cavity mirror 30. Discrete cavity mirror 31. Laser crystal 32. Cavity mirror 33. Reflecting mirror 34. Shaping mirror assembly 35. Reflecting mirror 36. Discrete cavity mirror 37. Discrete cavity mirror 38. Discrete cavity mirror 39. Laser crystal 40. Shaping mirror assembly 41. Reflecting mirror 42. Cavity mirror 43. Detailed Implementation

[0011] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] This invention provides an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure, comprising an all-solid-state continuous single-frequency seed module 1, a polarization-maintaining fiber coupler 7, a fiber pulse modulation module 2, a fiber pre-amplification module 3, a slab laser pre-amplification module 4, a polarization-maintaining fiber collimator 8, a shaping module 9, a slab laser main amplification module 5, and a frequency doubling module 6, arranged sequentially.

[0013] The all-solid-state continuous single-frequency seed module 1 generates a 10mW single-frequency linearly polarized laser, which is output to the fiber pulse modulation module 2 via the polarization-maintaining fiber coupler 7. The fiber pulse modulation module 2 pulse modulates the incident single-frequency linearly polarized laser to obtain a single-frequency high repetition rate pulse laser with an adjustable repetition rate of 50Hz~10kHz and a pulse width of <35ns. The pulse laser is then output to the fiber pre-amplification module 3. The fiber pre-amplification module 3 amplifies the incident single-frequency high repetition rate pulse laser to the nJ or even pJ level. The laser output from the polarization-maintaining fiber collimator 8 and the shaping module 9 is then sent to the slab laser pre-amplification module 4 via the reflector 10. The slab laser pre-amplification module 4 amplifies the incident laser to the mJ level based on spherical aberration self-compensation and discrete cavity mirror structure. The laser is then output to the slab laser main amplification module 5 via the reflector 17 and the reflector 19. The slab laser main amplification module 5 receives the laser and further amplifies it to the level of nearly 100mJ before outputting it to the frequency doubling module 6. The frequency doubling module 6 receives the laser and performs frequency doubling to generate a 532nm laser.

[0014] The all-solid-state continuous single-frequency seed module 1 is based on a four-mirror ring cavity configuration and can output continuous single-frequency linearly polarized laser.

[0015] The polarization-maintaining fiber coupler 7 is used to couple the single-frequency linearly polarized laser output from the all-solid-state continuous single-frequency seed module 1 to the polarization-maintaining fiber.

[0016] The fiber pulse modulation module 2 is used to modulate continuous single-frequency linearly polarized laser into single-frequency high repetition rate pulse laser. The fiber pulse modulation module 2 operates based on a fiber electro-optic modulator.

[0017] The fiber optic pre-amplification module 3 is used to amplify low-power, single-frequency, high-repetition-rate pulsed laser to the μJ level.

[0018] The polarization-maintaining fiber collimator 8 is used to collimate and output a single-frequency high-repetition-rate pulsed laser as a space laser.

[0019] The shaping module 9 is used to shape the laser output from the collimated fiber so that it can be amplified by the laser crystal later.

[0020] The slab laser pre-amplification module 4 includes a shaping mirror group 18, a laser crystal 15, a cavity mirror 16, and a discrete cavity mirror group composed of discrete cavity mirrors 11, 12, 13, and 14. The shaping mirror group 18 is used to shape the laser output from the slab laser pre-amplification module 4. The laser crystal 15 serves as the laser gain medium. The cavity mirror 16 and the discrete cavity mirror group together form the amplifier cavity mirror.

[0021] The slab laser main amplification module 5 includes three main amplifier stages: a first-stage main amplifier, a second-stage main amplifier, and a third-stage main amplifier. The laser output from the first-stage main amplifier is reflected by mirror 34 and enters the second-stage main amplifier. The laser output from the second-stage main amplifier is reflected by mirror 36 and enters the third-stage main amplifier. The laser output from the third-stage main amplifier is reflected by mirror 42 and output to cavity mirror 43, where it is further frequency-doubled by frequency multiplier module 6 before being output. This is used for 1064nm laser optical path deflection.

[0022] The first-stage main amplifier includes a shaping mirror group 27, a laser crystal 25, a cavity mirror 26, and a discrete cavity mirror group consisting of discrete cavity mirrors 21, 22, 23, and 24. The shaping mirror group 27 is used to shape the output laser, the laser crystal 25 serves as the laser gain medium, and the cavity mirror 26 and the discrete cavity mirror group together form the amplifier cavity mirror.

[0023] The second-stage main amplifier includes a shaping mirror assembly 35, a laser crystal 32, a cavity mirror 33, and a discrete cavity mirror assembly consisting of discrete cavity mirrors 28, 29, 30, and 31. The shaping mirror assembly 35 is used to shape the output laser, the laser crystal 32 serves as the laser gain medium, and the cavity mirror 33 and the discrete cavity mirror assembly together form the amplifier cavity mirror.

[0024] The third-stage main amplifier includes a shaping mirror group 41, a laser crystal 40, a cavity mirror 43, and a discrete cavity mirror group consisting of discrete cavity mirrors 37, 38, and 39. The shaping mirror group 41 is used to shape the output laser, the laser crystal 40 serves as the laser gain medium, and the cavity mirror 43 and the discrete cavity mirror group together form the amplifier cavity mirror.

[0025] Frequency multiplier module 6 is used to multiply the frequency of 1064nm laser to 532nm laser.

[0026] Discrete cavity mirrors 11-14, 21-24, 28-31, and 37-39 adopt a discrete configuration to suppress ASE, and the side closest to the laser crystal is coated with a 1064nm total reflection film.

[0027] The laser crystal 15 is made of Nd:YVO4 with a doping concentration of 0.3 at.%, and is cut using the a-cut method.

[0028] Laser crystals 25, 32, and 40 are made of Nd:YAG with a doping concentration of 0.7 at.%. <111> Cutting method.

[0029] Reflectors 10, 17, 19, 34, 36, and 42 are used for refracting the 1064nm laser beam path.

[0030] like Figure 1 As shown in the diagram, this invention provides a schematic of an all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure. It includes an all-solid-state continuous single-frequency seed module 1 capable of outputting a single-frequency continuous 1064nm laser. Spatial light is coupled into the polarization-maintaining fiber via a polarization-maintaining fiber coupler 7, modulated into a high-repetition-rate pulsed laser by the fiber pulse, amplified to the μJ level by the fiber pulse, and then collimated by a polarization-maintaining fiber collimator 8 before being output to a slab laser pre-amplification module. The laser is then amplified to the mJ level by an Nd:YVO4 laser crystal, and after beam shaping, enters the slab laser main amplification module 5, where it is amplified to nearly 100 mJ. The laser gain medium of the slab laser main amplification module 5 is Nd:YAG. Finally, a 532nm laser is output by a frequency doubling module 6.

[0031] The fiber pulse modulation module 2 is based on a polarization-maintaining fiber electro-optic modulator and is used to modulate continuous laser into pulsed laser.

[0032] The fiber preamplification module 3 is typically selected as a ytterbium-doped fiber amplifier.

[0033] The shaping module 9 is used to shape the laser output from the fiber to match the pump light mode distribution in the laser crystal.

[0034] Nd:YVO4 laser crystals are slab-shaped. Compared with Nd:YAG, Nd:YVO4 has a higher absorption coefficient and a larger stimulated emission cross section for pump light, making it suitable for gain amplification of small signal lasers.

[0035] Nd:YAG laser crystals are slab-shaped. Compared with Nd:YVO4, the high thermal conductivity of Nd:YAG is conducive to efficient heat transfer, enabling the crystal to withstand high-power laser operation.

[0036] like Figure 2 The image shown is a measured light spot image output by the slab fiber pre-amplification module 4 provided in this embodiment.

[0037] The specific embodiments described above illustrate the technical solution and beneficial effects of the present invention in detail. It should be understood that the above description is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fully solid-state high-power single-frequency laser based on a fiber-slab hybrid structure, characterized in that, It includes, in sequence, an all-solid-state continuous single-frequency seed module, an optical fiber pulse modulation module, an optical fiber pre-amplification module, a slab laser pre-amplification module, a slab laser main amplification module, and a frequency doubling module; The all-solid-state continuous single-frequency seed module generates a single-frequency linearly polarized laser output to the fiber pulse modulation module. The fiber pulse modulation module modulates the incident single-frequency linearly polarized laser pulse into a single-frequency high-repetition-rate laser pulse and outputs it to the fiber pre-amplification module. The fiber pre-amplification module amplifies the incident single-frequency high-repetition-rate laser and outputs it to the slab laser pre-amplification module. The slab laser pre-amplification module amplifies the incident single-frequency high-repetition-rate laser and outputs it to the slab laser main amplification module. The slab laser main amplification module receives the single-frequency high-repetition-rate laser, amplifies it further, and outputs it to the frequency doubling module. The frequency doubling module receives the single-frequency high-repetition-rate laser, multiplies it, and outputs the laser. The slab laser pre-amplification module includes a shaping mirror group, a laser crystal, a cavity mirror, and a discrete cavity mirror group. The shaping mirror group is used to shape the laser output from the slab laser pre-amplification module. The laser crystal serves as the laser gain medium. The cavity mirror and the discrete cavity mirror group together form the amplifier cavity mirror.

2. The all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The all-solid-state continuous single-frequency seed module is based on a four-mirror ring cavity configuration and outputs continuous single-frequency linearly polarized laser.

3. The all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, A polarization-maintaining fiber coupler is placed between the all-solid-state continuous single-frequency seed module and the fiber pulse modulation module to couple the single-frequency laser output from the all-solid-state continuous single-frequency seed module to the polarization-maintaining fiber.

4. The all-solid-state high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The single-frequency high repetition rate pulsed laser has an adjustable repetition rate of 50Hz~10kHz, and the fiber pulse modulation module works based on a fiber electro-optic modulator.

5. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The fiber optic pre-amplification module is used to amplify single-frequency high-repetition-rate lasers to the pJ level.

6. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The laser output from the fiber pre-amplification module passes sequentially through a polarization-maintaining fiber collimator and a shaping module before entering the slab laser pre-amplification module. The polarization-maintaining fiber collimator is used to collimate the laser output as a space laser, and the shaping module is used to shape the space laser.

7. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The slab laser main amplifier module includes three main amplifier stages: a first-stage main amplifier, a second-stage main amplifier, and a third-stage main amplifier. The laser output from the first-stage main amplifier is reflected by a mirror and then enters the second-stage main amplifier. The laser output from the second-stage main amplifier is reflected by a mirror and then enters the third-stage main amplifier. The laser output from the third-stage main amplifier is reflected by a mirror and then further frequency-multiplied by a frequency multiplier before being output.

8. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 7, characterized in that, The first-stage main amplifier includes a shaping mirror group, a laser crystal, a cavity mirror, and a discrete cavity mirror group; the shaping mirror group is used to shape the output laser, the laser crystal serves as the laser gain medium, and the cavity mirror and the discrete cavity mirror group together form the amplifier cavity mirror.

9. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 8, characterized in that, The second-stage main amplifier includes a shaping mirror assembly, a laser crystal, a cavity mirror, and a discrete cavity mirror assembly. The shaping mirror assembly is used to shape the output laser, the laser crystal serves as the laser gain medium, and the cavity mirror and the discrete cavity mirror assembly together form the amplifier cavity mirror.

10. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 9, characterized in that, The third-stage main amplifier includes a shaping mirror assembly, a laser crystal, a cavity mirror, and a discrete cavity mirror assembly. The shaping mirror assembly is used to shape the output laser, the laser crystal serves as the laser gain medium, and the cavity mirror and the discrete cavity mirror assembly together form the amplifier cavity mirror.

11. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The laser output from the shaping module is reflected by a mirror to the slab laser pre-amplification module; the laser output from the slab laser pre-amplification module is output to the slab laser main amplification module via two mirrors.

12. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 7 or 10, characterized in that, The mirror is used for reflecting and deflecting 1064nm light.

13. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The frequency doubling module is used to double the frequency of a 1064nm laser to a 532nm laser.

14. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 10, characterized in that, The discrete mirror groups of the first-stage main amplifier, the second-stage main amplifier, and the third-stage main amplifier all include multiple discrete mirrors. The discrete mirrors have a discrete configuration and the side closest to the laser crystal is coated with a 1064nm total reflection film.

15. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 1, characterized in that, The laser crystal of the slab laser pre-amplification module is made of Nd:YVO4 with a doping concentration of 0.3 at.%, and is cut using the a-cut method.

16. A high-power single-frequency laser based on a fiber-slab hybrid structure according to claim 10, characterized in that, The laser crystals for the first-stage, second-stage, and third-stage main amplifiers are Nd:YAG with a doping concentration of 0.7 at.%. <111> Cutting method.

Images