A reflective multi-pass end-pumping structure

Abstract

This invention relates to the field of laser manufacturing technology, and in particular to a reflective multi-path incident end-face pumping structure, comprising a pump source, a collimating lens group, a strip-shaped gain medium, and a reflective component disposed on at least one side of the strip-shaped gain medium; the collimating lens group is located between the pump source and the strip-shaped gain medium; during operation, the pump light output from the pump source is collimated by the collimating lens group and projected onto the end face of the strip-shaped gain medium; through the cooperation of the reflective component and the strip-shaped gain medium, the pump light acts on the strip-shaped gain medium in a multi-path incident manner and forms reflection propagation. Thus, on the one hand, the effective range of the pump light and the strip-shaped gain medium is expanded, avoiding concentrated absorption of the pump light near the end face of the strip-shaped gain medium, thereby alleviating the problem of steep axial temperature gradient inside the strip-shaped gain medium; on the other hand, the utilization rate of the pump light is improved, achieving higher stimulated emission efficiency without additionally increasing the pump power of the pump source.

Description

Technical Field

[0001] This invention relates to the field of laser manufacturing technology, and in particular to a reflective multi-path incident end-face pumping structure. Background Technology

[0002] In the field of laser technology, the pump structure, as a core component of a laser, directly determines the laser's output power, beam quality, and operational stability through its design rationality. Laser end-face pumping is one of the commonly used pumping methods for solid-state lasers. Its core characteristic is that the pump light is incident along the end face of the laser crystal, and the propagation direction of the pump light is essentially coincident with the optical axis of the laser resonator. Due to its advantages such as high coupling efficiency and good laser mode, it is widely used in miniaturized solid-state lasers with low threshold and high beam quality, becoming the mainstream pump coupling method for medium- and low-power solid-state lasers.

[0003] However, existing end-pumping technology has significant drawbacks such as concentrated thermal effects and difficulty in thermal management. The reason for this is that the pump light is incident along the gain medium axis, and the energy is concentrated and absorbed near the end face, resulting in a steep axial temperature gradient inside the medium, which is much larger than the radial heat distribution of side pumping. This causes a severe thermal lensing effect (the refractive index increases with temperature, and the crystal is equivalent to a convex lens), which in turn causes serious consequences such as resonant cavity parameter drift, changes in beam divergence angle, and reduction in laser energy. Even with temperature control and adaptive cavity type, it is difficult to completely eliminate this effect, which greatly limits its application in high-power, wide-adaptability scenarios.

[0004] To address the aforementioned issues, various improvement schemes have been proposed in related fields. For example, Chinese invention patent (CN114725763A) proposes a composite crystal and a high-power dual-end pumping device. The crystal doping concentration increases from both ends to the middle. By changing the crystal doping concentration and the dual-end pumping method, the problems of uneven pump light absorption and uneven heat distribution inside the crystal are improved. Another example is Chinese invention patent (CN105591267A), which proposes a multi-wavelength pumped temperature-controlled solid-state laser and a multi-wavelength selection method. By coupling pump light of different wavelengths, the pump light absorption conversion efficiency and output laser power are stabilized, and the laser output performance is insensitive to changes in ambient temperature.

[0005] However, the existing improvement schemes still have obvious defects: CN114725763A uses a composite crystal composed of five segments of crystals with different doping concentrations bonded together. The multi-segment bonding requires ensuring that the interface is defect-free and the refractive index is matched, which places extremely high demands on the bonding process precision, significantly increasing the manufacturing cost and the difficulty of controlling the yield. At the same time, multiple sets of dichroic mirrors are added to the pump structure, further complicating the laser structure. CN105591267A only achieves the stability of the pump light absorption conversion efficiency at different temperatures, but does not solve the core problem of uneven heat distribution inside the crystal caused by the excessive absorption of pump light near the end face.

[0006] In addition, some existing multi-pump schemes are complex in structure and require the introduction of a large number of optical components, which not only increases the system size and cost, but also increases optical loss. Furthermore, the performance of the gain medium is prone to degradation due to heat accumulation during high-power operation, which will inevitably affect the long-term operational stability of the laser.

[0007] Therefore, it is imperative for our technical personnel to solve the above-mentioned problems. Summary of the Invention

[0008] The purpose of this invention is to provide a reflective multi-path incident end-face pumping structure, which aims to solve the problems of concentrated end-face pumping heat effect and uneven heat distribution in existing designs, as well as the complex structure, high cost, large optical loss and poor operational stability of multi-path pumping schemes.

[0009] This invention relates to a reflective multi-path incident end-face pumping structure, comprising a pump light source, a collimating lens group, a strip-shaped gain medium, and a reflective component disposed on at least one side of the strip-shaped gain medium; the collimating lens group is disposed between the pump light source and the strip-shaped gain medium; the pump light output from the pump light source is collimated by the collimating lens group and projected onto the end face of the strip-shaped gain medium; the reflective component is used to cooperate with the strip-shaped gain medium to make the pump light act on the strip-shaped gain medium in a multi-path incident manner, and to make the pump light incident on the strip-shaped gain medium reflect and propagate between the reflective component and the strip-shaped gain medium.

[0010] As a further improvement to the technical solution disclosed in this invention, the pump light source is preferably a diode array with a pump power of 150 to 300W, and the wavelength type of the output pump light is a single wavelength or a combination of multiple wavelengths.

[0011] As a further improvement to the technical solution disclosed in this invention, the strip-shaped gain medium is preferably an Nd:YAG crystal with a concentration of 0.2 to 1.5 at.%.

[0012] As a preferred embodiment, the reflective component includes a triangular pure YAG crystal and a reflective film; the triangular pure YAG crystal is used to change the propagation direction of the pump light and is attached to the sidewall of the strip-shaped gain medium; the reflective film is disposed on the side surface of the triangular pure YAG crystal facing away from the strip-shaped gain medium.

[0013] As a further improvement to the technical solution disclosed in this invention, the long right-angle side of the triangular pure YAG crystal is equivalent to the length of the strip-shaped gain medium, and its acute angle α is 10° to 45°; the reflectivity of the reflective film to the pump light is not less than 99.5%.

[0014] Of course, as another modified design of the above technical solution, the reflective component can also be preferably a reflector; the reflector is arranged at an angle relative to the strip gain medium, with an angle β of 10° to 45°, and is used to cooperate with the strip gain medium to change the propagation direction of the pump light.

[0015] As a further improvement to the technical solution disclosed in this invention, both the pump light incident surface of the strip-shaped gain medium and the reflective component are coated with an anti-reflection film, and the transmittance of the anti-reflection film to the pump light is not less than 99.5%.

[0016] As a further improvement to the technical solution disclosed in this invention, the reflective multi-path incident end-face pump structure also includes a heat sink; the heat sink is attached to the side surface of the reflective component away from the strip-shaped gain medium, and is used to remove the heat generated by the reflective component and the strip-shaped gain medium during operation through conduction cooling.

[0017] As a preferred embodiment, the number of reflective components is two, and they are symmetrically arranged on both sides of the strip-shaped gain medium.

[0018] Of course, as another preferred option, the number of reflective components is 1, and they are arranged on one side of the strip-shaped gain medium.

[0019] In practical applications, the reflective multi-path incident end-face pumping structure disclosed in this invention can achieve at least the following beneficial technical effects, specifically: 1) By combining the reflective component with the strip-shaped gain medium, the pump light is incident on the gain medium in a multi-path manner, and the pump light propagates through reflection between the two, effectively expanding the interaction range between the pump light and the gain medium. This avoids concentrated absorption of the pump light near the end face, significantly alleviates the problem of steep axial temperature gradient, reduces the influence of thermal lensing effect, and thus improves the stability and beam quality of laser output. At the same time, the multi-path reflection propagation design effectively improves the utilization rate of the pump light, achieving higher stimulated emission efficiency without increasing pump power, thus meeting the needs of high-power applications. 2) The laser does not require complex multi-segment bonding crystals or a large number of optical components. It does not require overcoming the challenges of high-precision bonding processes, nor does it require the addition of auxiliary optical components such as dichroic mirrors. This not only significantly reduces the difficulty and cost of crystal preparation and device assembly, but also reduces optical losses caused by multiple interfaces and multiple optical components, which is conducive to improving the transmission efficiency of pump light. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the optical path and component layout of the first embodiment of the reflective multi-path incident end-face pumping structure disclosed in this invention.

[0022] Figure 2 This is a schematic diagram of the optical path and component layout of the second embodiment of the reflective multi-path incident end-face pumping structure disclosed in this invention.

[0023] Figure 3 This is a schematic diagram of the optical path and component layout of the third embodiment of the reflective multi-path incident end-face pumping structure disclosed in this invention.

[0024] Figure 4 This is a schematic diagram of the optical path and component layout of the fourth embodiment of the reflective multi-path incident end-face pumping structure disclosed in this invention.

[0025] 1-Diode array; 2-Collimating lens group; 3-Strip Nd:YAG crystal; 4-Middle antireflective coating; 5-Upper triangular pure YAG crystal; 6-Upper reflective coating; 7-Upper antireflective coating; 8-Lower triangular pure YAG crystal; 9-Lower reflective coating; 10-Lower antireflective coating; 11-Upper reflector; 12-Lower reflector. Detailed Implementation

[0026] The invention will be further described in detail below with reference to specific embodiments. The reflective multi-path incident end-face pump structure, as the core energy coupling and transmission unit of the laser, aims to optimize the pump light energy distribution and improve laser output performance. The following four specific embodiments, in conjunction with corresponding accompanying drawings, illustrate in detail the structural design, workflow, and overall performance advantages of different configuration schemes.

[0027] Example 1: Single-sided arrangement of triangular pure YAG crystal reflective component This embodiment employs a single-sided triangular pure YAG crystal reflective component design, suitable for applications requiring structural simplicity and lightweight construction. Its optical path and component layout are as follows: Figure 1 As shown.

[0028] The reflective multi-path incident end-face pump structure of this embodiment mainly consists of a diode array 1, a collimating lens group 2, a strip-shaped Nd:YAG crystal 3, a mid-position antireflection film 4, an upper triangular pure YAG crystal 5, an upper reflective film 6, and an upper antireflection film 7. The heat sink (not shown in the figure) serves as a supporting heat dissipation component, and is tightly attached to the side of the upper triangular pure YAG crystal 5 that is away from the strip-shaped Nd:YAG crystal 3, providing heat dissipation assurance for the stable operation of the structure.

[0029] Diode array 1 serves as the pump source, providing a stable and controllable energy input to the system. Its pump power is set between 150 and 300W, and the output pump light wavelength can be selected as a single wavelength or a combination of multiple wavelengths according to actual application requirements, providing flexible scene adaptability. Collimating lens group 2 is located between diode array 1 and strip Nd:YAG crystal 3, responsible for shaping and collimating the pump light output from diode array 1 to ensure that the beam has good parallelism and concentration.

[0030] The strip-shaped Nd:YAG crystal 3 serves as the strip-shaped gain medium and is the core carrier for pump light absorption and laser energy conversion. Its concentration is controlled at 0.2–1.5 at.%, which can balance thermal stability while ensuring pump light absorption efficiency. The intermediate antireflection film 4 is deposited on the end face of the strip-shaped Nd:YAG crystal 3, and its transmittance to pump light is not less than 99.5%.

[0031] The upper triangular pure YAG crystal 5 serves as the core optical path steering component of the reflective assembly. Its long right-angled side is precisely matched to the length of the strip-shaped Nd:YAG crystal 3, ensuring that the pump light can cover the key active area of ​​the strip-shaped Nd:YAG crystal 3, achieving uniform incidence. Furthermore, the acute angle α of the upper triangular pure YAG crystal 5 is set between 10° and 45° to guide the pump light to form an optimal propagation path, ensuring that the reflected pump light can again efficiently act on the strip-shaped Nd:YAG crystal 3. The upper triangular pure YAG crystal 5 is tightly fitted to the upper sidewall of the strip-shaped Nd:YAG crystal 3 to ensure the stability of the optical path propagation.

[0032] The upper reflective film 6, made of a high-reflectivity material, is fixedly mounted on the surface of the upper triangular pure YAG crystal 5 facing away from the strip-shaped Nd:YAG crystal 3. Its reflectivity to pump light is not less than 99.5%, maximizing pump light reflection and reducing energy attenuation during reflection. The upper antireflection film 7 is located on the side of the upper triangular pure YAG crystal 5 facing the incident pump light, also with a transmittance of not less than 99.5%. Together with the middle antireflection film 4, it forms a low-loss optical transmission channel throughout the entire transmission path, further reducing interface loss during light transmission.

[0033] During operation, the pump light output from diode array 1 is first collimated and shaped by collimating lens group 2 to form a beam with high parallelism and concentrated energy. Subsequently, part of the beam is vertically projected through the middle antireflection film 4 to the end face of the strip-shaped Nd:YAG crystal 3 and enters its interior, while another part of the beam is vertically projected through the upper antireflection film 7 to the end face of the upper triangular pure YAG crystal 5 and enters its interior. The pump light entering the strip-shaped Nd:YAG crystal 3 is directly absorbed and converted into laser energy, while the pump light entering the upper triangular pure YAG crystal 5 is transmitted to the upper reflective film 6 under its angular guidance. After being reflected by the upper reflective film 6, it is refracted back into the strip-shaped Nd:YAG crystal 3, forming a multi-path incident reflection propagation path.

[0034] Throughout the entire operation, the heat sink continuously removes the heat generated by the upper triangular pure YAG crystal 5 and the strip-shaped Nd:YAG crystal 3, effectively controlling the component temperature and preventing heat accumulation from affecting material performance and optical path stability.

[0035] Example 2: Symmetrical arrangement of triangular pure YAG crystal reflective components on both sides This embodiment employs a symmetrically arranged triangular pure YAG crystal reflector design to maximize the uniformity of pump light distribution, adapting to high-power, high-precision applications. Its optical path and component layout are as follows: Figure 2 As shown.

[0036] The reflective multi-path incident end-face pump structure of this embodiment mainly consists of a diode array 1, a collimating lens group 2, a strip-shaped Nd:YAG crystal 3, a middle anti-reflection film 4, an upper triangular pure YAG crystal 5, an upper reflective film 6, an upper anti-reflection film 7, a lower triangular pure YAG crystal 8, a lower reflective film 9, and a lower anti-reflection film 10. The heat sink (not shown in the figure) is closely attached to the side surface of the upper triangular pure YAG crystal 5 and the lower triangular pure YAG crystal 8 that is away from the strip-shaped Nd:YAG crystal 3, respectively, to construct a dual-sided synchronous heat dissipation system.

[0037] Diode array 1 serves as the pump light source, with a pump power set between 150 and 300W. The output wavelength can be selected as a single wavelength or a combination of multiple wavelengths as needed, providing a stable and sufficient energy input to the system. Collimating lens group 2 is positioned between diode array 1 and strip-shaped Nd:YAG crystal 3 to shape and collimate the pump light, ensuring excellent parallelism and concentration of the beam, thus providing a foundation for uniform propagation of the reflected light path on both sides.

[0038] The strip-shaped Nd:YAG crystal 3 serves as the core gain medium, with a concentration controlled between 0.2% and 1.5 at.%, balancing pump light absorption efficiency and thermal stability. Its end face is coated with a mid-position antireflection film 4, ensuring a pump light transmittance of no less than 99.5%, significantly reducing interface loss at the incident end. The upper triangular pure YAG crystal 5 and the lower triangular pure YAG crystal 8 have identical structural parameters; their long right-angle sides are strictly matched to the length of the strip-shaped Nd:YAG crystal 3, and the acute angle α is set between 10° and 45° to ensure symmetrical and efficient optical paths on both sides. The upper triangular pure YAG crystal 5 and the lower triangular pure YAG crystal 8 are tightly fitted to the upper and lower sidewalls of the strip-shaped Nd:YAG crystal 3, respectively, to eliminate optical path deviation and energy loss caused by interface gaps.

[0039] The upper reflective film 6 and the lower reflective film 9 are fixed on the surface of the upper triangular pure YAG crystal 5 and the lower triangular pure YAG crystal 8 respectively, away from the strip-shaped Nd:YAG crystal 3, and the reflectivity of the pump light is not less than 99.5%, minimizing the attenuation of reflected energy; the upper antireflection film 7 and the lower antireflection film 10 are respectively disposed on the end face of the upper triangular pure YAG crystal 5 and the lower triangular pure YAG crystal 8, and the transmittance of both is not less than 99.5%, together with the middle antireflection film 4, forming a low-loss optical transmission channel for the entire link.

[0040] During operation, the pump light output from diode array 1 is collimated by collimating lens group 2. Part of the beam is vertically projected through the middle antireflection film 4 to the end face of strip-shaped Nd:YAG crystal 3 and enters its interior. The other part of the beam is vertically projected through the upper antireflection film 7 and the lower antireflection film 10 to the end faces of the upper triangular pure YAG crystal 5 and the lower triangular pure YAG crystal 8 and enters their respective interiors. The pump light entering strip-shaped Nd:YAG crystal 3 is directly absorbed and converted, while the pump light entering upper triangular pure YAG crystal 5 is reflected by upper reflective film 6 and refracted back. The pump light entering lower triangular pure YAG crystal 8 is reflected by lower reflective film 9 and refracted back, forming a symmetrical multi-path reflection propagation path that fully covers the entire length of strip-shaped Nd:YAG crystal 3.

[0041] During operation, the heat sink continuously removes the heat generated by the double-sided triangular pure YAG crystal and the strip-shaped Nd:YAG crystal, effectively controlling the overall temperature and avoiding performance degradation caused by heat accumulation.

[0042] Example 3: Single-sided arrangement of reflective mirror assembly This embodiment employs a single-sided reflective mirror assembly design, which is the most streamlined configuration and suitable for miniaturized, portable lasers. Its optical path and assembly layout are as follows: Figure 3 As shown.

[0043] The reflective multi-path incident end-face pump structure of this embodiment mainly consists of a diode array 1, a collimating lens group 2, a strip-shaped Nd:YAG crystal 3, a mid-position antireflection film 4, and an upper-position reflector 11. The heat sink (not shown in the figure) is closely attached to the side of the upper-position reflector 11 that is away from the strip-shaped Nd:YAG crystal 3, providing directional heat dissipation for the structure.

[0044] Diode array 1 serves as the pump light source, with a pump power set between 150 and 300W. The output wavelength can be flexibly selected as a single wavelength or a combination of multiple wavelengths according to the application scenario, providing a stable energy input to the system. Collimating lens group 2 is located between diode array 1 and strip-shaped Nd:YAG crystal 3, responsible for shaping and collimating the pump light to ensure good beam parallelism, laying the foundation for subsequent reflection and propagation.

[0045] The strip-shaped Nd:YAG crystal 3 serves as the gain medium, with a concentration controlled between 0.2% and 1.5 at.%, ensuring efficient absorption and energy conversion of the pump light. A mid-level antireflection film 4 is coated on the end face of the strip-shaped Nd:YAG crystal 3, with a pump light transmittance of no less than 99.5%, significantly reducing interface reflection loss at the incident end and improving light energy utilization. The upper reflector 11, as a reflective component, employs a high-reflectivity optical lens, achieving a pump light reflectance of no less than 99.5%, thus efficiently reflecting the pump light to reduce energy attenuation. The upper reflector 11 is tilted relative to the strip-shaped Nd:YAG crystal 3, with a tilt angle β set between 10° and 45°. By precisely adjusting the β angle, the pump light reflection direction can be controlled, ensuring that the reflected pump light can re-enter the strip-shaped Nd:YAG crystal 3 to form an effective effect.

[0046] During operation, the pump light output from diode array 1 is first collimated and shaped by collimating lens group 2 to form a beam with high parallelism and concentrated energy. Subsequently, part of the beam is vertically projected onto the end face of strip Nd:YAG crystal 3 through the central antireflection film 4 and enters its interior, while the other part of the beam is reflected by the upper reflector 11 and changes its propagation direction before entering strip Nd:YAG crystal 3. The two parts of the pump light together form a multi-path incident effect within strip Nd:YAG crystal 3, which fully expands the interaction range between the pump light and strip Nd:YAG crystal 3 and ensures that the energy is fully absorbed and converted.

[0047] The heat sink promptly removes the heat generated by the upper reflector 11 and the strip Nd:YAG crystal 3 during operation, preventing the temperature rise from affecting the performance of the component.

[0048] Example 4: Symmetrical arrangement of reflective mirror components on both sides This embodiment employs a symmetrically arranged reflector assembly design on both sides, balancing pump light uniformity with structural convenience. Its optical path and assembly layout are as follows: Figure 4 As shown.

[0049] The reflective multi-path incident end-face pump structure of this embodiment mainly consists of a diode array 1, a collimating lens group 2, a strip-shaped Nd:YAG crystal 3, a mid-position anti-reflection film 4, an upper reflector 11, and a lower reflector 12. The heat sink (not shown in the figure) is closely attached to the side surface of the upper reflector 11 and the lower reflector 12 that is away from the strip-shaped Nd:YAG crystal 3, respectively, to construct a dual-sided high-efficiency heat dissipation system.

[0050] Diode array 1 serves as the pump light source, with a pump power set between 150 and 300W. The output wavelength can be selected as a single wavelength or a combination of multiple wavelengths according to actual needs, providing a stable and sufficient energy input to the system. Collimating lens group 2 is positioned between diode array 1 and strip-shaped Nd:YAG crystal 3 to shape and collimate the pump light, ensuring excellent beam parallelism and guaranteeing a symmetrical reflection path on both sides.

[0051] The strip-shaped Nd:YAG crystal 3 serves as the core gain medium, with its concentration controlled between 0.2% and 1.5 at.%, maintaining good energy conversion characteristics. The end face of the strip-shaped Nd:YAG crystal 3 is coated with a mid-position antireflection film 4, ensuring a transmittance of no less than 99.5% for pump light, thus guaranteeing efficient pump light incidence and reducing interface reflection loss. Both the upper reflector 11 and the lower reflector 12 are high-reflectivity optical lenses, with a reflectivity of no less than 99.5% for pump light, ensuring stable and reliable reflection performance. The upper reflector 11 and the lower reflector 12 are arranged at an angle relative to the strip-shaped Nd:YAG crystal 3, with the tilt angle β uniformly set between 10° and 45°. This symmetrical angle design ensures that the pump light forms a uniform propagation path after double-sided reflection, thereby fully covering the strip-shaped Nd:YAG crystal 3.

[0052] During operation, the pump light output from diode array 1 is first collimated and shaped by collimating lens group 2 to form a beam with high parallelism and concentrated energy. Subsequently, part of the beam is vertically projected onto the end face of strip-shaped Nd:YAG crystal 3 through the central antireflection film 4 and enters its interior. The other two parts of the beam are reflected by the upper reflector 11 and the lower reflector 12 respectively, changing their propagation direction, and then enter the strip-shaped Nd:YAG crystal 3 together. The three parts of the pump light form a symmetrical multi-path incident propagation effect in the strip-shaped Nd:YAG crystal 3, so that the pump light can fully interact with the strip-shaped Nd:YAG crystal 3 and improve the full utilization of energy.

[0053] During operation, the heat sink simultaneously removes the heat generated by the double-sided reflectors and the strip-shaped Nd:YAG crystal 3, effectively controlling the operating temperature of the entire structure and preventing heat accumulation from affecting performance.

[0054] Although Examples 1, 2, 3, and 4 differ in the type and arrangement of reflective components, they are all based on the core design concept of this invention. Through the organic integration and synergistic work of the various components, multiple performance advantages are achieved, specifically: 1) All embodiments utilize a reflective component (including an assembly of an upper triangular pure YAG crystal 5 and an upper reflective film 6, an assembly of a lower triangular pure YAG crystal 8 and a lower reflective film 9, an upper reflector 11, and a lower reflector 12) in conjunction with a strip-shaped Nd:YAG crystal 3 to construct a multi-path incident and reflection propagation path for the pump light. This effectively expands the interaction range between the pump light and the strip-shaped Nd:YAG crystal 3, resulting in a more uniform energy distribution and improved pump light utilization, thereby ensuring the stability and beam quality of the laser output. Furthermore, the rational optical path design allows the pump light to fully participate in energy conversion, achieving efficient stimulated emission without additional pump power. 2) Each embodiment adopts a simple component combination. The complete pump optical path is constructed by the direct cooperation of diode array 1, collimating lens group 2, strip Nd:YAG crystal 3 and reflection component. There is no need for complex multi-segment bonding process or a large number of auxiliary optical components. In this way, not only is the fabrication and assembly difficulty of the structure reduced, but also the interface loss in the light transmission process is reduced, ensuring energy transmission efficiency.

[0055] 3) The heat sink and reflective component are designed to be closely integrated, which enables efficient heat dissipation, effectively controls the working temperature of the strip Nd:YAG crystal 3 and the reflective component, avoids the impact of heat accumulation on component performance, and ensures the long-term stable operation of the entire structure under different power conditions.

[0056] Finally, it should be noted that each of the four embodiments has its own focus: Embodiment 1 is suitable for low-to-medium power, lightweight equipment; Embodiment 2 is suitable for high-end applications with high power and beam quality requirements; Embodiment 3 focuses on meeting the needs of miniaturized and portable lasers; Embodiment 4 balances uniformity and ease of assembly, and is suitable for standardized mass production.

[0057] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reflective multi-path incident end-face pumping structure, comprising a pump light source, a collimating lens group, a strip-shaped gain medium, and a reflective component disposed on at least one side of the strip-shaped gain medium; the collimating lens group is disposed between the pump light source and the strip-shaped gain medium; the pump light output from the pump light source is collimated by the collimating lens group and projected onto the end face of the strip-shaped gain medium; the reflective component is used to cooperate with the strip-shaped gain medium to cause the pump light to act on the strip-shaped gain medium in a multi-path incident manner, and to cause the pump light incident on the strip-shaped gain medium to be reflected and propagated between the reflective component and the strip-shaped gain medium.

2. The reflective multi-path incident end-face pumping structure according to claim 1, characterized in that, The pump light source is a diode array with a pump power of 150-300W, and the output pump light has a single wavelength or a combination of multiple wavelengths.

3. The reflective multi-path incident end-face pumping structure according to claim 1, characterized in that, The strip-shaped gain medium is an Nd:YAG crystal with a concentration of 0.2–1.5 at.%.

4. The reflective multi-path incident end-face pumping structure according to claim 1, characterized in that, The reflective component includes a triangular pure YAG crystal and a reflective film; the triangular pure YAG crystal is used to change the propagation direction of the pump light and is attached to the sidewall of the strip-shaped gain medium; the reflective film is disposed on the side surface of the triangular pure YAG crystal facing away from the strip-shaped gain medium.

5. The reflective multi-path incident end-face pumping structure according to claim 4, characterized in that, The long right-angled side of the triangular pure YAG crystal is equivalent to the length of the strip-shaped gain medium, and its acute angle α is 10° to 45°; the reflectivity of the reflective film to pump light is not less than 99.5%.

6. The reflective multi-path incident end-face pumping structure according to claim 1, characterized in that, The reflecting component is a reflector; the reflector is arranged at an angle β of 10° to 45° relative to the strip-shaped gain medium, and is used to cooperate with the strip-shaped gain medium to change the propagation direction of the pump light.

7. The reflective multi-path incident end-face pumping structure according to claim 1, characterized in that, Both the strip-shaped gain medium and the pump light incident surface of the reflective component are coated with an anti-reflection film, and the transmittance of the anti-reflection film to the pump light is not less than 99.5%.

8. The reflective multi-path incident end-face pumping structure according to claim 1, characterized in that, It also includes a heat sink; the heat sink is attached to the surface of the reflective component away from the strip-shaped gain medium, and is used to remove the heat generated by the reflective component and the strip-shaped gain medium during operation by means of conduction cooling.

9. The reflective multi-path incident end-face pumping structure according to any one of claims 1-8, characterized in that, The number of the reflective components is two, and they are symmetrically arranged on both sides of the strip-shaped gain medium.

10. The reflective multi-path incident end-face pumping structure according to any one of claims 1-8, characterized in that, The number of the reflective components is one, and they are arranged on one side of the strip-shaped gain medium.

Images