V-cavity high-efficiency solid-state laser amplifier

Abstract

This invention relates to a V-cavity high-efficiency solid-state laser amplifier, belonging to the field of solid-state laser technology. It includes: a laser gain module for amplifying the energy of a signal light; a pump system for providing unidirectional pump light and injecting it into the laser gain module; a V-shaped reflection optical path system composed of a first reflector and a second reflector, wherein the first reflector is a high-reflectivity mirror and the second reflector is an output coupling mirror, arranged in a V-shape; and a cooling component for temperature control of the laser gain module. The signal light is reflected sequentially by the first reflector in the V-shaped reflection optical path system, then passes through the laser gain module twice to achieve double-pass amplification, and is finally output by the second reflector. The laser gain module uses Nd:YVO4, Nd:YAG, or Yb:YAG crystal as the gain medium. This invention significantly improves amplification efficiency, provides good beam quality, has a compact and easily adjustable structure, and exhibits good thermal stability.

Description

Technical Field

[0001] This invention relates to the field of solid-state laser technology, specifically a V-cavity high-efficiency solid-state laser amplifier. Background Technology

[0002] Solid-state laser amplifiers, as core components of laser systems, are primarily used to amplify the energy of seed light to meet the energy requirements of various applications. Currently, the mainstream implementation schemes for solid-state laser amplifiers fall into two main categories: one is the straight-through amplifier, where the beam passes through the gain medium only once, resulting in a relatively simple structure; the other is the M-type multi-path amplifier, which uses a complex array of mirrors to achieve multiple beam reflections, thereby increasing the interaction distance between the beam and the gain medium.

[0003] However, both of the above-mentioned existing solutions have significant drawbacks in practical applications, making it difficult to balance amplification efficiency, structural complexity, and beam output quality. The specific problems are as follows: Low efficiency: Under single-ended pumping conditions, traditional through-type amplifiers have a short interaction distance between the beam and the gain medium, resulting in low energy utilization and uneven gain distribution.

[0004] Complex structure: To improve efficiency, multi-end pumping or M-type multi-optical-path structures are used, which are bulky, extremely difficult to adjust the optical path, and expensive.

[0005] Significant thermal effects: Under high-power pumping, the gain crystal is prone to thermal lensing, which leads to a severe deterioration in the output beam quality.

[0006] Therefore, those skilled in the art have provided a V-cavity high-efficiency solid-state laser amplifier to solve the problems mentioned in the background art. Summary of the Invention

[0007] This invention aims to solve the problems of low energy utilization, complex optical path structure, and difficult thermal management in existing solid-state laser amplifiers under single-ended pumping conditions. Through an innovative V-shaped cavity design, high-efficiency two-way amplification is achieved while maintaining a compact structure.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A V-cavity high-efficiency solid-state laser amplifier, comprising: Laser gain module, used to amplify the energy of signal light; A pumping system is used to provide unidirectional pump light and inject it into the laser gain module; The V-shaped reflection optical path system consists of a first reflector and a second reflector. The first reflector is a high-reflection mirror, and the second reflector is an output coupling mirror (i.e., a partial reflector). The two are arranged in a V-shape. Cooling components are used for temperature control of the laser gain module; In this system, the signal light is reflected sequentially by the first reflector in the V-shaped reflection optical path system, then passes through the laser gain module twice to achieve double-pass amplification, and is finally output by the second reflector.

[0009] As a further aspect of the present invention, the laser gain module uses Nd:YVO4, Nd:YAG or Yb:YAG crystal as the gain medium.

[0010] As a further embodiment of the present invention: the length of the laser gain module is 10-50mm, and the end face is coated with a film layer with a reflectivity ≥99.8%.

[0011] As a further aspect of the present invention, the included angle between the first reflector and the second reflector is 20° to 40°.

[0012] As a further embodiment of the present invention: the pumping system includes a pump light source, an optical fiber coupler and a collimating lens group, used to precisely inject pump light into the center of the incident surface of the laser gain module.

[0013] As a further embodiment of the present invention: the cooling assembly includes a thermally conductive copper base and a water-cooled substrate, and the water cooling flow rate is 0.5 to 1.5 L / min.

[0014] As a further aspect of the present invention, the transmittance of the second reflector is 5% to 15%.

[0015] As a further aspect of the present invention, the deviation angle between the crystal axis of the laser gain module and the incident direction of the pump light is 0° to 3°.

[0016] As a further aspect of the present invention: the V-shaped reflection optical path system is configured such that the optical paths passing through the laser gain module twice intersect inside the gain medium, and the spatial overlap rate between the pump light and the signal light is greater than 85%.

[0017] As a further aspect of the present invention, it also includes a main control drive board and an angle adjustment mechanism. The main control drive board is used to monitor the output power in real time and to fine-tune the angle of the second reflector through the angle adjustment mechanism to compensate for optical path thermal drift.

[0018] Compared with the prior art, the beneficial effects of the present invention are: Significantly improved amplification efficiency: Through the V-shaped two-way structure, the energy utilization rate under single-end pumping is increased by about 30%, and the overall amplification efficiency can reach more than 60%.

[0019] High beam quality: The optimized optical path design ensures that the spatial overlap between the pump light and the signal light is greater than 85%, resulting in a high output beam quality M. 2<1.3.

[0020] Compact and easy to adjust: Compared with the complex optical path of the M-type, the V-type structure is simple, small in size, and easy to assemble, adjust and maintain.

[0021] Good thermal stability: The efficient water-cooling structure combined with the uniform gain distribution effectively suppresses the thermal lensing effect. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a V-cavity high-efficiency solid-state laser amplifier; Figure 2 This is a combined view of the pump source, cooling components, and main control drive board in a V-cavity high-efficiency solid-state laser amplifier. Figure 3 This is a diagram of the V-shaped reflection optical path layout of this application; Figure 4 This is a schematic diagram of the two-way optical propagation principle of this application.

[0023] In the diagram: 1. Laser gain module; 2. Pump source; 3. Collimating lens group; 4. First reflecting mirror; 5. Second reflecting mirror; 6. V-shaped reflection optical path system; 7. Cooling assembly; 8. Output mirror; 9. Main control drive board. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0025] As mentioned in the background section of this application, research has revealed that existing solid-state laser amplifiers suffer from low energy efficiency, complex optical path structures, and difficulties in thermal management under single-ended pumping conditions.

[0026] To address the aforementioned shortcomings, this application discloses a V-cavity high-efficiency solid-state laser amplifier, which significantly improves amplification efficiency, provides good beam quality, has a compact and easily adjustable structure, and exhibits good thermal stability.

[0027] The following will describe in detail, with reference to the accompanying drawings, how the solution of this application solves the above-mentioned technical problems.

[0028] Please see Figure 1 and Figure 2In this embodiment of the invention, a V-cavity high-efficiency solid-state laser amplifier includes: a laser gain module 1 for amplifying the energy of a signal light; a pumping system for providing unidirectional pump light and injecting it into the laser gain module 1; a V-shaped reflection optical path system 6, consisting of a first reflecting mirror 4 and a second reflecting mirror 5, wherein the first reflecting mirror 4 is a high-reflectivity mirror and the second reflecting mirror 5 is an output coupling mirror (i.e., a partial reflecting mirror), and the two are arranged in a V-shape; and a cooling component 7 for temperature control of the laser gain module 1. The signal light, after being reflected sequentially by the first reflecting mirror 4 in the V-shaped reflection optical path system 6, passes through the laser gain module 1 twice, achieving double-pass amplification, and is finally output by the second reflecting mirror 5. Through the combination of the V-shaped reflection optical path and the single-ended pumping, the signal light passes through the gain medium twice, significantly improving the energy extraction efficiency under compact structural conditions.

[0029] In this embodiment, the laser gain module 1 uses Nd:YVO4, Nd:YAG, or Yb:YAG crystals as the gain medium. Selecting these crystals provides high gain, low threshold voltage, and good thermal conductivity, adapting to the pumping and amplification requirements of different wavelengths.

[0030] In this embodiment, the length of the laser gain module 1 is 10–50 mm, and its end face is coated with a film with a reflectivity ≥99.8%. Limiting the length range ensures sufficient gain length while controlling the thermal lensing effect, and the high-reflectivity film reduces end face loss and prevents parasitic oscillations.

[0031] In this embodiment, the angle between the first reflector 4 and the second reflector 5 is 20° to 40°. This angle range ensures that the optical paths passing through the gain medium twice intersect internally, achieving a high spatial overlap rate and avoiding optical path interference.

[0032] In this embodiment, the pumping system includes a pump light source 2, an optical fiber coupler, and a collimating lens group 3, used to precisely inject pump light into the center of the incident surface of the laser gain module 1. The optical fiber coupler and the collimating lens group 3 improve the pump light injection efficiency, concentrate the pump energy in the central region of the gain medium, and enhance the gain uniformity.

[0033] In this embodiment, the cooling assembly 7 includes a thermally conductive copper base and a water-cooled substrate, with a water flow rate of 0.5–1.5 L / min. The combination of the copper base and water cooling achieves efficient heat conduction, and controlling the flow rate range can achieve a balance between heat dissipation capacity and vibration noise, suppressing the thermal lensing effect.

[0034] In this embodiment, the transmittance of the second reflector 5 is 5% to 15%. This transmittance range allows the output coupler to maximize energy output while maintaining sufficient gain within the cavity, avoiding over-coupling that leads to efficiency degradation.

[0035] In this embodiment, the deviation angle between the crystal axis of the laser gain module 1 and the incident direction of the pump light is 0° to 3°. A small deviation angle can disrupt the resonance condition of parasitic oscillations without affecting the spatial overlap between the pump light and the signal light, thus improving amplification stability.

[0036] In this embodiment, the V-shaped reflection optical path system 6 is configured such that the optical paths passing through the laser gain module 1 twice intersect within the gain medium, and the spatial overlap between the pump light and the signal light is greater than 85%. The intersection of the optical paths and the high overlap ensure that the pump energy is fully extracted by the signal light, reducing unused pump areas, thereby improving amplification efficiency and beam quality.

[0037] In this embodiment, a main control drive board 9 and an angle adjustment mechanism are also included. The main control drive board 9 is used to monitor the output power in real time and to fine-tune the angle of the second reflector 5 through the angle adjustment mechanism to compensate for thermal drift of the optical path. The main control drive board 9 and the angle adjustment mechanism form a closed-loop feedback to automatically compensate for thermally induced optical path offset and ensure the stability of output power and beam direction under long-term operation.

[0038] This invention provides a V-cavity high-efficiency solid-state laser amplifier. Its core working principle utilizes a V-shaped reflection optical path system 6 to achieve two-way passage of signal light within the laser gain module 1, thereby significantly improving amplification efficiency under single-end pumping conditions. The specific workflow is as follows: I. Pump light injection: Pump light (typically a semiconductor laser with wavelength matching the absorption peak of the gain medium) is emitted from pump source 2. After beam shaping and collimation by collimating lens group 3, it is precisely injected into the center of the incident surface of laser gain module 1. The pump light is absorbed within laser gain module 1, forming a population inversion distribution, which provides gain for signal light amplification.

[0039] II. Signal optical two-way amplification process: First stage of amplification: The external seed signal light enters the laser gain module 1 along the preset path, and passes through the pumped and excited gain medium for the first time, and the signal light energy is initially amplified.

[0040] V-shaped optical path reversal: The signal light, after being amplified in the first stage, is directed towards the first reflecting mirror 4 in the V-shaped reflective optical path system 6 (this mirror is a high-reflectivity mirror with a reflectivity of >99.5% for signal light). The signal light is reflected by the first reflecting mirror 4, changing its propagation direction and returning along the other arm of the V-shaped optical path.

[0041] Second amplification: The returning signal light passes through laser gain module 1 a second time, utilizing the remaining pump energy for further amplification. The two paths intersect within the gain medium, resulting in a spatial overlap of more than 85% between the pump light and the signal light, thus maximizing energy extraction efficiency.

[0042] Output coupling: The signal light, after two-way amplification, finally reaches the second reflecting mirror 5 in the V-shaped reflection optical path system 6. This mirror is the output coupling mirror (i.e., a partial reflecting mirror) with a transmittance of 5% to 15%. Most of the signal light is reflected back into the cavity to maintain oscillation or for further amplification, while the transmitted portion serves as the amplified laser output, emitted outward through the output mirror 8 (which can be understood as an output window or auxiliary calibration mirror), such as... Figure 3 and Figure 4 As shown.

[0043] III. Temperature Control and Thermal Management: During the amplification process, the laser gain module 1 generates heat. The cooling component 7 is tightly attached to the outside of the laser gain module 1 and typically includes a thermally conductive copper base and a water-cooled substrate. Cooling water is circulated at a flow rate of 0.5 to 1.5 L / min to stabilize the crystal temperature within a set range (e.g., 25℃ ± 1℃), effectively suppressing the thermal lensing effect and ensuring beam quality.

[0044] IV. Intelligent Feedback and Adjustment: The main control driver board 9 is the control core of the entire amplifier. It monitors parameters such as output power and temperature in real time and is connected to an angle adjustment mechanism (not shown in the figure, which is a use of existing technology but falls within the control scope of the main control driver board 9). When optical path drift is detected (such as a change in the angle of the reflector due to thermal effects), the main control driver board 9 automatically issues a command to fine-tune the overall attitude of the second reflector 5 or the V-shaped reflection optical path system 6 to compensate for thermal drift and ensure that the two-way optical path is always in the best coupling state, achieving long-term stable operation.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A V-cavity high-efficiency solid-state laser amplifier, characterized in that, include: Laser gain module, used to amplify the energy of signal light; A pumping system is used to provide unidirectional pump light and inject it into the laser gain module; The V-shaped reflection optical path system consists of a first reflector and a second reflector. The first reflector is a high-reflection mirror, and the second reflector is an output coupling mirror. The two are arranged in a V-shape. Cooling components are used for temperature control of the laser gain module; In this system, the signal light is reflected sequentially by the first reflector in the V-shaped reflection optical path system, then passes through the laser gain module twice to achieve double-pass amplification, and is finally output by the second reflector.

2. The V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The laser gain module uses Nd:YVO4, Nd:YAG or Yb:YAG crystals as the gain medium.

3. The V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The laser gain module has a length of 10-50 mm and its end face is coated with a film with a reflectivity of ≥99.8%.

4. The V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The angle between the first reflector and the second reflector is 20° to 40°.

5. A V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The pumping system includes a pump source, an optical fiber coupler, and a collimating lens group, used to precisely inject pump light into the center of the incident surface of the laser gain module.

6. The V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The cooling assembly includes a thermally conductive copper base and a water-cooled substrate, with a water flow rate of 0.5–1.5 L / min.

7. A V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The transmittance of the second reflector is 5% to 15%.

8. A V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The deviation angle between the crystal axis of the laser gain module and the incident direction of the pump light is 0° to 3°.

9. A V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, The V-shaped reflection optical path system is configured such that the optical paths passing through the laser gain module twice intersect inside the gain medium, and the spatial overlap rate between the pump light and the signal light is greater than 85%.

10. A V-cavity high-efficiency solid-state laser amplifier according to claim 1, characterized in that, It also includes a main control drive board and an angle adjustment mechanism. The main control drive board is used to monitor the output power in real time and to fine-tune the angle of the second reflector through the angle adjustment mechanism to compensate for the thermal drift of the optical path.

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