Pumping source heat dissipation device and semiconductor pumping packaging nanosecond ultraviolet laser

Abstract

The invention relates to the technical field of laser, and discloses a pumping source heat dissipation device which comprises a ceramic substrate, a vapor chamber, a fin radiator and a first cooling system which are fixedly connected in sequence. A first groove, a second groove and a filling working medium are formed in the uniform temperature plate, the first groove is opposite to the second groove, a first space is formed between the first groove and the second groove, and the filling working medium is located in the first space; the fin radiator comprises a plurality of fin units which are fixedly connected in sequence; and the areas of the bottom surfaces of the ceramic substrate, the vapor chamber, the fin radiator and the cooling system are sequentially increased. According to the pumping source heat dissipation device provided by the invention, the ceramic substrate, the vapor chamber, the fin radiator and the cooling system are connected in sequence, and the structural design that the bottom surface area is increased step by step is adopted, so that rapid diffusion and efficient export of heat of the pumping source are realized, the junction temperature of a pumping chip is effectively reduced, the working stability of the pumping source is improved, and the service life of the pumping source is prolonged.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and in particular to a pump source heat dissipation device and a semiconductor-pumped packaged nanosecond ultraviolet laser. Background Technology

[0002] In the current field of laser technology, ultraviolet lasers, due to their unique advantages such as short wavelength, high single-photon energy, and the ability to be focused into very small spots, have significant application value in many fields, including integrated circuit technology, precision laser processing, and life sciences. In the field of precision manufacturing, solid-state nanosecond ultraviolet pulsed lasers are extremely important core light sources, and high-power nanosecond ultraviolet light sources are indispensable in the field of high-precision cutting.

[0003] Traditional semiconductor-pumped ultraviolet lasers often employ fiber coupling to transmit pump light to the gain medium. However, this method has several drawbacks. Firstly, fiber coupling leads to pump light power loss, reducing the overall efficiency of the laser. Secondly, the introduction of fiber increases system complexity and cost, and the flexibility of fiber makes it susceptible to bending, stretching, and other external forces in practical applications, thus affecting the transmission quality and stability of the pump light. Furthermore, achieving pump light matching with the laser mode typically requires a complex optical coupling system, which not only increases the system's size and weight but also makes system debugging and maintenance more difficult. Regarding pump source heat dissipation, traditional designs struggle to meet the heat dissipation requirements under high power density, and the performance and structural design of the pump chip also affect the output quality and efficiency of the pump light. Summary of the Invention

[0004] The present invention aims to improve at least one technical problem in the prior art.

[0005] The first aspect of the present invention provides a pump source heat dissipation device, comprising a ceramic substrate, a heat spreader, a finned heat sink, and a first cooling system that are fixedly connected in sequence; The ceramic substrate is used to conduct heat from the pump chip to the heat spreader. The heat spreader has a first groove, a second groove and a filling medium inside. The first groove and the second groove are opposite to each other, and a first space is formed between the first groove and the second groove. The filling medium is located in the first space. The finned radiator includes multiple finned units, which are fixedly connected in sequence. The area of ​​the bottom surface of the ceramic substrate, the heat spreader, the finned radiator, and the first cooling system increases sequentially.

[0006] As a further improvement to the above technical solution, the first cooling system is a water-cooled system or an air-cooled system.

[0007] As a further improvement to the above technical solution, the depth-to-width ratio of the first trench is 1.5:1, and the depth-to-width ratio of the second trench is 1.5:1.

[0008] A second aspect of the present invention provides a semiconductor-pumped packaged nanosecond ultraviolet laser, comprising a pump source, a resonant cavity, a gain medium, a Q-switching device, a second harmonic crystal, and a third harmonic crystal; The pump source includes a semiconductor laser and a pump source heat dissipation device as described above. The semiconductor laser is used to emit pump light and includes a pump chip, which is fixedly connected to the ceramic substrate. The resonant cavity includes a first reflector and a second reflector. Along the optical path of the pump light, the first reflector, the gain medium, the Q-switching device, the second harmonic crystal, the third harmonic crystal, and the second reflector are arranged sequentially. The first reflector has high reflectivity for the fundamental frequency light and high transmittance for the pump light. The second reflector has high reflectivity for both the fundamental frequency light and the harmonic light and high transmittance for ultraviolet light.

[0009] As a further improvement to the above technical solution, the pump source further includes a microlens array. Along the optical path direction of the pump light, the microlens array is located between the semiconductor laser and the first reflector, and the microlens array is used to reduce the divergence angle of the pump light.

[0010] As a further improvement to the above technical solution, the semiconductor-pumped packaged nanosecond ultraviolet laser also includes a first heat sink, a second heat sink, a second cooling system, and a third cooling system; The first heat sink is fixedly connected to the pump source and is used to conduct heat from the pump source. The second cooling system is fixedly connected to the first heat sink and is used to dissipate heat from the first heat sink. The second heat sink is fixedly connected to the resonant cavity and is used to conduct heat from the resonant cavity. The third cooling system is fixedly connected to the resonant cavity and is used to dissipate heat from the resonant cavity.

[0011] As a further improvement to the above technical solution, the output wavelength of the semiconductor laser is 878nm.

[0012] As a further improvement to the above technical solution, the gain medium is a neodymium vanadate crystal with a neodymium ion doping concentration of 0.25 at%.

[0013] The beneficial effects of this invention are: The pump source heat dissipation device provided by the present invention achieves rapid diffusion and efficient heat dissipation of the pump source by sequentially connecting a high thermal conductivity ceramic substrate, a heat spreader, a finned heat sink and a cooling system, and adopting a structural design with a gradually increasing bottom area. This effectively reduces the junction temperature of the pump chip and improves the working stability and service life of the pump source.

[0014] The semiconductor-pumped packaged nanosecond ultraviolet laser provided by this invention has no fiber coupling. The pump source uses the above-mentioned pump source heat dissipation device. By combining the high-efficiency heat dissipation pump source with a reasonably configured resonant cavity structure, the pump efficiency and cavity stability are improved. Attached Figure Description

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of an embodiment of the pump source heat dissipation device of the present invention; Figure 2 This is a cross-sectional structural schematic diagram of an embodiment of the pump source heat dissipation device of the present invention; Figure 3 This is a schematic diagram of the structure of an embodiment of the semiconductor-pumped packaged nanosecond ultraviolet laser of the present invention.

[0016] In the attached figures: 11-Ceramic substrate; 12-Population plate; 121-First trench; 122-Second trench; 123-Working medium; 13-Finned heat sink; 14-First cooling system; 15-Pump chip; 16-Microlens array; 23-First reflector; 24-Second reflector; 25-Gain medium; 26-Q-switching device; 27-Second harmonic crystal; 28-Third harmonic crystal. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] The following is combined Figures 1 to 3 Embodiments of the present invention will be described.

[0019] Reference Figure 1 and Figure 2 This embodiment relates to a pump source heat dissipation device, which includes a ceramic substrate 11, a heat spreader 12, a finned heat sink 13 and a first cooling system 14 that are fixedly connected in sequence. The ceramic substrate 11 is used to conduct the heat of the pump chip 15 to the heat spreader 12; The temperature distribution plate 12 has a first groove 121, a second groove 122 and a filling medium 123 inside. The first groove 121 and the second groove 122 are opposite to each other, and a first space is formed between the first groove 121 and the second groove 122. The filling medium 123 is located in the first space. The finned radiator 13 includes multiple finned units, which are fixedly connected in sequence. The area of ​​the bottom surface of the ceramic substrate 11, the heat spreader 12, the finned radiator 13, and the first cooling system 14 increases sequentially.

[0020] In this embodiment, by sequentially connecting the high thermal conductivity ceramic substrate 11, the heat spreader 12, the finned heat sink 13 and the cooling system, and adopting a structural design with progressively increasing bottom area, the rapid diffusion and efficient removal of heat from the pump source are achieved, effectively reducing the junction temperature of the pump chip 15 and improving the working stability and service life of the pump source.

[0021] Specifically, the pump source heat dissipation device includes a high thermal conductivity ceramic substrate 11, a heat spreader 12, a finned heat sink 13, and a first cooling system 14. These components are sequentially fixed along the heat conduction direction. The ceramic substrate 11 is fixed to one side of the heat spreader 12 by welding or thermally conductive adhesive, serving to support the pump chip 15 and rapidly conduct the heat generated by the pump chip 15 to the heat spreader 12. The heat spreader 12 and the finned heat sink 13 are fixedly connected by vacuum welding. The heat spreader 12 has a first groove 121 and a second groove 122 inside, which are opposite to each other, forming a first space filled with a working fluid 123. The working fluid 123 can be an ammonia-water azeotropic mixture (NH3 20wt% + H2O 80wt%). The heat spreader 12 and the finned heat sink 13 can be fixedly connected by mechanical means, such as using screws, with thermally conductive silicone grease applied to their contact surfaces, the thickness uniformly controlled at 0.1-0.2 mm. During pump source operation, the working fluid 123 undergoes a phase change in the heat absorption zone and releases heat in the condensation zone, thereby achieving rapid heat diffusion within the heat spreader 12. The finned radiator 13 includes multiple finned units, with adjacent finned units sequentially fixedly connected to form spaced heat dissipation channels, increasing the heat exchange area with the cooling medium. The first cooling system 14 is fixedly installed on the outside or bottom of the finned radiator 13 for active heat dissipation. The bottom surface areas of the ceramic substrate 11, heat spreader 12, finned radiator 13, and first cooling system 14 increase sequentially along the heat conduction direction, causing the heat flux density to decrease gradually, thereby improving overall heat dissipation efficiency.

[0022] In some embodiments, the first cooling system 14 is a water-cooled system or an air-cooled system.

[0023] In this embodiment, the first cooling system 14 can be a water-cooled system or an air-cooled system. The heat dissipation scheme can be flexibly selected according to different power levels and application environments, balancing heat dissipation efficiency and system cost, and improving the applicability of the pump source heat dissipation device. Specifically, the first cooling system 14 can be a water-cooled system, for example, including cooling water channels, a water pump, and heat exchange pipes. The cooling water channels are fitted closely to the finned heat sink 13, and cooling water circulates within the channels to remove heat from the finned heat sink 13. The first cooling system 14 can also be an air-cooled system, for example, including a fan and an air guide structure. The fan is fixedly installed on one side of the finned heat sink 13, and heat dissipation is achieved by forcing airflow through the fin gaps.

[0024] Reference Figure 2 In some embodiments, the aspect ratio of the first trench 121 is 1.5:1, and the aspect ratio of the second trench 122 is 1.5:1.

[0025] In this embodiment, the depth-to-width ratio of the first groove 121 and the second groove 122 is preferably 1.5:1, which improves the phase change efficiency and reflux stability of the medium filling the heat exchanger 12, thereby enhancing the heat dissipation capacity of the heat exchanger 12 and further improving the heat dissipation performance of the pump source. Specifically, the depth-to-width ratio of both the first groove 121 and the second groove 122 is 1.5:1. This structural parameter allows a suitable capillary structure to be formed inside the groove, which is beneficial for the filling working fluid 123 to generate a stable reflux channel during the phase change process, thereby forming an efficient heat circulation path inside the heat exchanger 12.

[0026] Reference Figure 3 This embodiment relates to a semiconductor-pumped packaged nanosecond ultraviolet laser, including a pump source, a resonant cavity, a gain medium 25, a Q-switching device 26, a second harmonic crystal 27, and a third harmonic crystal 28; The pump source includes a semiconductor laser and a pump source heat dissipation device as described above. The semiconductor laser is used to emit pump light. The semiconductor laser includes a pump chip 15, which is fixedly connected to the ceramic substrate 11. The resonant cavity includes a first reflector 23 and a second reflector 24. Along the optical path of the pump light, the first reflector 23, the gain medium 25, the Q-switching device 26, the second harmonic crystal 27, the third harmonic crystal 28, and the second reflector 24 are arranged sequentially. The first reflector 23 has high reflectivity for fundamental frequency light and high transmittance for pump light. The second reflector 24 has high reflectivity for both fundamental frequency light and harmonic light and high transmittance for ultraviolet light.

[0027] In this embodiment, by combining a high-efficiency heat-dissipating pump source with a rationally configured resonant cavity structure, pump efficiency and intracavity stability are improved. The pump chip 15 in the semiconductor laser is fixedly connected to the ceramic substrate 11 in the aforementioned pump source heat dissipation device, thereby rapidly transferring the heat generated by the pump chip 15 during operation to the heat dissipation device. Specifically, the ceramic substrate 11 and the pump chip 15 can be bonded together with silver paste to ensure that the thermal resistance between them is minimized. The thickness of the silver paste layer is controlled at 5-10 μm, allowing heat to be quickly transferred from the pump chip 15 to the ceramic substrate 11. The Q-switching device is used to control the loss of the resonant cavity and realize nanosecond pulsed laser output. The second harmonic crystal 27 adopts a suitable nonlinear optical crystal such as KTP to convert the fundamental frequency light into a second harmonic. The third harmonic crystal 28 adopts a crystal such as LBO to sum the remaining fundamental frequency light with the second harmonic to generate ultraviolet light.

[0028] Reference Figure 3 In some embodiments, the pump source further includes a microlens array 16 located between the semiconductor laser and the first reflector 23 along the optical path direction of the pump light. The microlens array 16 is used to reduce the divergence angle of the pump light.

[0029] In one embodiment, the pump source further includes a microlens array 16, which is fixedly installed between the semiconductor laser and the first reflector 23 and is arranged along the optical path direction of the pump light.

[0030] In this embodiment, by setting the microlens array 16, the spatial matching degree and coupling efficiency of the pump light are improved, thereby enhancing the overall photoelectric conversion efficiency and output stability of the laser. Specifically, the microlens array 16 is used to shape and collimate the pump light output from the semiconductor laser to reduce the divergence angle of the pump light, allowing the pump light to be coupled more concentratedly into the gain medium 25.

[0031] In some embodiments, the semiconductor-pumped packaged nanosecond ultraviolet laser further includes a first heat sink, a second heat sink, a second cooling system, and a third cooling system; The first heat sink is fixedly connected to the pump source and is used to conduct heat from the pump source. The second cooling system is fixedly connected to the first heat sink and is used to dissipate heat from the first heat sink. The second heat sink is fixedly connected to the resonant cavity and is used to conduct heat from the resonant cavity. The third cooling system is fixedly connected to the resonant cavity and is used to dissipate heat from the resonant cavity.

[0032] In this embodiment, by setting independent heat dissipation paths for the pump source and the resonant cavity, the mutual influence of heat is avoided, thereby improving the overall thermal management capability and long-term operational stability of the device. Specifically, the first heat sink is fixedly connected to the pump source to conduct the heat generated by the pump source; the second cooling system is fixedly connected to the first heat sink to dissipate heat; the second heat sink is fixedly connected to the resonant cavity to conduct the heat generated by the optical components inside the resonant cavity; and the third cooling system is fixedly connected to the second heat sink to dissipate heat.

[0033] In some embodiments, the output wavelength of the semiconductor laser is 878 nm.

[0034] In this embodiment, an 878 nm pump wavelength is used to effectively reduce quantum defects, reduce the generation of ineffective heat, improve laser efficiency, and reduce the heat dissipation burden.

[0035] In some embodiments, the gain medium 25 is a neodymium-doped yttrium vanadate crystal with a neodymium ion doping concentration of 0.25 at%. In this embodiment, by selecting a neodymium-doped yttrium vanadate crystal with a low doping concentration, the thermal effect is reduced while ensuring sufficient gain, which is beneficial for obtaining high-quality and high-stability nanosecond ultraviolet laser output.

[0036] The preferred embodiments of the present invention have been described in detail above, but the present disclosure is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of the present disclosure.

[0037] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0038] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

Claims

1. A pump source heat dissipation device, characterized in that: It includes a ceramic substrate (11), a heat spreader (12), a finned heat sink (13), and a first cooling system (14) that are fixedly connected in sequence. The ceramic substrate (11) is used to conduct the heat of the pump chip (15) to the heat spreader (12). The heat spreader (12) has a first groove (121), a second groove (122) and a filling medium (123) inside. The first groove (121) and the second groove (122) are opposite to each other, and a first space is formed between the first groove (121) and the second groove (122). The filling medium (123) is located in the first space. The finned radiator (13) includes multiple finned units, which are fixedly connected in sequence. The area of ​​the bottom surface of the ceramic substrate (11), the heat spreader (12), the finned radiator (13), and the first cooling system (14) increases sequentially.

2. The pump source heat dissipation device according to claim 1, characterized in that: The first cooling system (14) is a water-cooled system or an air-cooled system.

3. The pump source heat dissipation device according to claim 1, characterized in that: The first trench (121) has a depth-to-width ratio of 1.5:1, and the second trench (122) has a depth-to-width ratio of 1.5:

1.

4. A semiconductor-pumped packaged nanosecond ultraviolet laser, characterized in that: It includes a pump source, a resonant cavity, a gain medium (25), a Q-switching device (26), a second harmonic crystal (27), and a third harmonic crystal (28). The pump source includes a semiconductor laser and a pump source heat dissipation device as described in any one of claims 1-3. The semiconductor laser is used to emit pump light. The semiconductor laser includes a pump chip (15). The pump chip (15) is fixedly connected to the ceramic substrate (11). The resonant cavity includes a first reflector (23) and a second reflector (24). Along the optical path of the pump light, the first reflector (23), the gain medium (25), the Q-switching device (26), the second harmonic crystal (27), the third harmonic crystal (28), and the second reflector (24) are arranged in sequence. The first reflector (23) has high reflectivity for the fundamental frequency light and high transmittance for the pump light. The second reflector (24) has high reflectivity for both the fundamental frequency light and the harmonic light and high transmittance for ultraviolet light.

5. The semiconductor-pumped packaged nanosecond ultraviolet laser according to claim 4, characterized in that: The pump source also includes a microlens array (16). Along the optical path of the pump light, the microlens array (16) is located between the semiconductor laser and the first reflector (23). The microlens array (16) is used to reduce the divergence angle of the pump light.

6. The semiconductor-pumped packaged nanosecond ultraviolet laser according to claim 4, characterized in that: The semiconductor-pumped packaged nanosecond ultraviolet laser also includes a first heat sink, a second heat sink, a second cooling system, and a third cooling system; The first heat sink is fixedly connected to the pump source and is used to conduct heat from the pump source. The second cooling system is fixedly connected to the first heat sink and is used to dissipate heat from the first heat sink. The second heat sink is fixedly connected to the resonant cavity and is used to conduct heat from the resonant cavity. The third cooling system is fixedly connected to the resonant cavity and is used to dissipate heat from the resonant cavity.

7. The semiconductor-pumped packaged nanosecond ultraviolet laser according to claim 4, characterized in that: The output wavelength of the semiconductor laser is 878nm.

8. The semiconductor-pumped packaged nanosecond ultraviolet laser according to claim 4, characterized in that: The gain medium (25) is a neodymium vanadate crystal with a neodymium ion doping concentration of 0.25 at%.

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